DOI： 10.2355/isijinternational.61.1055

researchmap

DOI： 10.2355/isijinternational.ISIJINT-2020-018

researchmap

DOI： 10.2355/isijinternational.ISIJINT-2020-502

researchmap

DOI： 10.2355/isijinternational.ISIJINT-2020-426

researchmap

DOI： 10.2320/matertrans.MT-M2020298

researchmap

DOI： 10.1051/matecconf/202032106002

researchmap

DOI： 10.2472/jsms.69.810

researchmap

Publishing type：Research paper (scientific journal)  

Stress corrosion cracking (SCC) behavior of SUS316L stainless steel in the chloride solution containing thiosulfate has been investigated by using a slow strain rate technique (SSRT). The susceptibility of SCC was found to depend on the strain rate, the concentration of thiosulfate and chloride, and pH. The highest susceptibility was obtained at the condition of 20 mass % NaCl containing 10-2 kmol·m-3 Na2S2O3 at pH 5.3 and 2.2 × 10-7 s-1. Observations of fractured specimens showed that cracks perpendicular to the tensile axis generated at the pits. The initial fracture mode of the crack was intergranular, followed by transgranular and dimple with propagation of the crack. Intergranular fracture initiated from intergranular corrosion on the bottom of the pit, in which pH decreased less than 2. Immediately after immersion, pits generated easily because the dissolved oxygen with thiosulfate rapidly raise free corrosion potential upto pitting potential in cooperation with the action of thiosulfate to lower the pitting potential. Decrease in pH caused lowering of pitting potential and increase of the number of cracks, while the highest SCC susceptibility was obtained at pH 5.3. At conditions showing the high SCC susceptibility, corrosion potential was always in the range between -400 and -370 mV (Ag/AgCl). Therefore, the SCC behavior in this system is strongly controlled by the electrochemical factors.

DOI： 10.2355/tetsutohagane1955.77.9_1511

Scopus

researchmap

DOI： 10.34562/jic.59.1_161

researchmap

DOI： 10.34562/jic.59.1_156

researchmap

DOI： 10.3323/jcorr.69.73

researchmap

J-GLOBAL

researchmap

DOI： 10.2320/jinstmet.J2018034

researchmap

DOI： 10.3323/jcorr.67.375

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Institute of Metals (JIM)  

In this study, we aimed to understand the corrosion behavior of Pb-free Cu alloys (Japan Industrial Standards (JIS) CAC411 and CAC901) and their crystallized substances (Cu2S and Bi, respectively) particles in a 3.0 mass% NaCl aqueous solution, in comparison with those of a Cu alloy (JIS CAC406), its crystallized substance (Pb) particles. and a Cu alloy (JIS CAC403) with no crystallized substances. A Cu2S specimen was produced via sintering Cu2S powders, and a Bi specimen was produced by Bi electro-plating on a Cu substrate. The measured corrosion potentials of CAC411, CAC901, and CAC403 were close to that of Sn instead Cu. The current density peak near the corrosion potential of CAC403, which was the highest Sn concentration, was the largest in comparison with those of the other Cu alloys. Conversely, rapid increase in the current density, which was shown for all the Cu alloy at the potential above -0.20 V vs. Ag/AgCl, was similar to that of Cu. Therefore, it was concluded that these increase in current densities of Cu alloys was due to the dissolution of the Cu matrix. Cu2S was converted into CuS during the anodic reaction. However, the corrosion potential of Cu2S was higher than those of Cu and CAC411. Therefore, it was concluded that the Cu2S particles in CAC411 act as cathodic sites and remain stable during the natural corrosion. The corrosion potential of Bi was higher than that of CAC901 and slightly lower than that of Cu. Further, at the potentials below -0.10 V vs. Ag/AgCl, Bi was thought to be covered with the passive film of Bi2O3 that was expected to protect Bi from corrosion. Therefore, it was concluded that the Bi particles in CAC901 hardly suffer severe corrosion. The corrosion potential of Pb was lower than those of the Cu and Cu alloys expect for CAC406. In addition, Pb exhibited a large anodic current density and dissolved actively around the corrosion potential of Cu. Therefore, it was concluded that the Pb particles dissolved preferentially during the corrosion of CAC406 owing to the galvanic corrosion. It was finally concluded that the Cu2S and the Bi particles in CAC411 and CAC901, respectively, hardly suffer severe corrosion than the Pb particles in CAC406 in chloride-containing aqueous solutions like sea water.

DOI： 10.2320/matertrans.M2017196

Scopus

researchmap

researchmap

researchmap

DOI： 10.4139/sfj.68.201

researchmap

researchmap

Publishing type：Research paper (international conference proceedings)  

© 2017 ICF 2017 - 14th International Conference on Fracture. All rights reserved. The research have tried to reveal the effect of annealing temperature on susceptibility to hydrogen embrittlement (HE) of the interstitial-free steel with ultra-fine grain (UFG) structure produced by an accumulative roll-bonding (ARB) method. The as-ARBed specimen exhibited the UFG structure with a large tensile strength. As hydrogen was introduced to the specimen, a fracture strain decreased remarkably. As the annealing temperature rose to 673 K, the tensile strength was slightly diminished. The fracture strain of the annealed specimen with hydrogen increased drastically with a rise in the annealing temperature. As the temperature further rose above 773 K, almost no change in the strain was obtained between the specimens with and without hydrogen, and the strength decreased remarkably.

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

Thin water film is formed on metal surfaces that are exposed to the atmosphere. The conditions of this film change according to environmental factors, such as temperature, wind, and rainfall. Hence, it is difficult to investigate atmospheric corrosion on metal surfaces.
This paper aimed to develop a measurement system for the pH distribution on a metal surface in simulated atmospheric environment. The surface pH distribution was measured with agar film including pH indicators and MgCl2. The pH indicators used were a universal indicator and an MR-BTB indicator. Agar film of 0.5 mm thickness was placed on an iron specimen. The specimen was set in a chamber with a relative humidity of 100% to prevent the agar film from drying out. The surface pH distribution was determined from the color of the agar film with an RGB color model. The surface pH distribution on the iron showed that anodic reactions produced acidic regions and cathodic reactions produced basic regions. The observed phenomena were the same as that found under a water droplet which contained the pH indicator and MgCl2. Therefore, we conclude that the agar film could simulate thin water film in an atmospheric environment and allow measurement of the surface pH distribution on iron under atmospheric corrosion.

DOI： 10.2320/jinstmet.JAW201704

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

This paper aimed to investigate conditions for pit initiation on type 304 stainless steel under MgCl2 solution layer in atmospheric environment using a CCD camera system and a surface potential measurement equipment. A droplet of dilute MgCl2 solution was put on the specimen. The specimen was set in the chamber with a relative humidity of 33% in order to make the droplet dry into the layer. The CCD camera system was employed to observe the change in the shape of the droplet and in the specimen surface during the drying process. In addition, the surface potential measurement equipment was applied for monitoring the surface potential of the specimen with the layer. When the droplet of dilute solution became thin and saturated, pitting corrosion occurred and the surface potential rapidly lowered. By contrast, thick and saturated layer did not induce pitting corrosion and the surface potential indicated the relatively low and steady. Therefore, it was revealed that the atmospheric corrosion occurred on the steel under saturated MgCl2 solution layer whose thickness less than 0.2 mm.

DOI： 10.2320/jinstmet.JAW201607

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Trans Tech Publications Ltd  

The behavior of environment-assisted cracking (EAC) for super-elastic TiNi alloy was investigated as functions of solution pH and electrochemical potential. The specimen was immersed in sulfate solutions at various pHs, and subjected to a potentiostatic slow strain rate tensile test. As a result, the EAC map for the TiNi alloy as functions of the solution pH and the applied potential was successfully produced, and it was revealed that larger EAC susceptibility was obtained in the region of lower potential and lower pH. The tendency was quite typical for hydrogen embrittlement, but not similar to that of TiAl. The EAC susceptibility was classified by cathodic charge density, irrespective to pH nor potential: The charge density larger than 0.025 MC.m-2 induced a maximum EAC susceptibility.

DOI： 10.4028/www.scientific.net/MSF.879.709

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers  

Hydrogen absorption behavior of the steels containing Cr and Ni has been investigated under cathodic polarization in sulfate solutions by means of conventional electrochemical hydrogen permeation test. Good agreement of the empirical with the theoretical transient curves of hydrogen permeation current density suggested quasi-equilibrium condition to the absorption-desorption reaction of hydrogen at the surface. In addition, a diffusion coefficient obtained from the transient curve decreased with an increase in a concentration of the additional elements, and the decrement was enhanced much more by Cr than by Ni. A hydrogen concentration at the hydrogen absorption surface was almost proportional to a square root of the cathodic current density for any specimens. The slope increased with an increase in a content of the additional elements, and the increment was enhanced much more by Cr than by Ni. The two findings suggested that the additional elements of Cr and Ni attract hydrogen, and that the attraction effect of Cr was much more than that of Ni.

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

We have investigated influence of concentrations of LiOH and Li2MoO4 on corrosion behavior of SS400 carbon steel immersed in concentrated LiBr solutions at 393 and 438 K for a short period about 0.2 ks. The corrosion behavior was evaluated by measurement of polarization curve. As a result, the following were obtained: Addition of LiOH to 65 mass% LiBr solution induced suppression of cathodic current around the corrosion potential to shift the corrosion potential lower. Further, two-step active dissolution current was found around the corrosion potential and passive current in the higher potential region. On the other hand, addition of 0.03 mass% Li2MoO4 to 65 mass% LiBr + 0.2 mass% LiOH solution induced small suppression of cathodic current around corrosion potential, and more addition of 0.06 mass% made the cathodic current slightly increase. Two-step active dissolution and passivation phenomena were found in the anodic polarization curve like those in the solution without Li2MoO4. The anodic current density was almost independent of the concentration of Li2MoO4. Corrosion rates of the steel immersed in various solutions at 393 K for the short period were almost the same as 1.5 A·m-2. In the solutions at 438 K, corrosion rate decreased with an increase in LiOH concentration and increased with an increase in Li2MoO4 concentration.

DOI： 10.3323/jcorr.65.264

Scopus

researchmap

researchmap

Language：Japanese   Publisher：Japan Society of Corrosion Engineering  

DOI： 10.3323/jcorr.65.43

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Effect of hardness of steels on hydrogen absorption behavior has been investigated by means of conventional electrochemical hydrogen permeation test. Empirical transient curves of hydrogen permeation current density were agreed with the theoretical one on the basis of Fick's second law with a fixed hydrogen concentration at the hydrogen absorption surface, C-0, at any time. The fact suggests quasi-equilibrium condition to the absorption-desorption reaction of hydrogen at the surface, and that correlation between C-0 and hydrogen absorption rate. As an analytical result of the transient, a diffusion coefficient of hydrogen, D, decreased with an increase in a hardness of the steel. On the other hand, the value of C-0 increased with an increase in the hardness. There was a good positive correlation between C-0 and an inverse of D in spite of difference in the hardness and the additional element. The fact may suggest that the microstructural defects attract hydrogen both in the bulk and on the surface of the steel, and the effect promotes hydrogen ad-atom absorbing into the iron specimen.

DOI： 10.2355/isijinternational.ISIJINT-2015-283

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

The susceptibility to environment-assisted cracking (EAC) of super-elastic TiNi alloy was investigated as a function of the electrochemical potential and solution pH. The investigation was conducted using a slow-strain-rate tensile test apparatus with a potentiostat. The test solutions were sulfate solutions with various pH values adjusted by H2SO4 or NaOH. The alloy deforming under cathodic reaction fractured under the relatively small strain where the alloy was in the stress-induced martensitic phase. A larger EAC susceptibility was obtained at lower potential and lower pH, which indicates that this is a general feature of hydrogen embrittlement. The severe EAC region of TiNi alloy was different from that of TiAl alloy. The EAC susceptibility was strongly correlated with the cathodic charge density, irrespective of the pH or potential: a charge density below 0.025 MC m(-2) yielded almost no EAC; however, above 0.025 MC m(-2) EAC was induced, and the EAC susceptibility was independent of the charge density. Hydrogen in solid-solution state was detected in the alloy at a charge density below 0.025 MC m(-2), and hydride started to form at a density above 0.025 MC m(-2).

DOI： 10.2320/matertrans.MI201511

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Effects of additional elements of Cr and Ni in iron on hydrogen absorption behavior have been investigated by means of conventional electrochemical hydrogen permeation test. Empirical transient curve of hydrogen permeation current density was agreed with theoretical one on the basis of Fick's second law with a fixed hydrogen concentration at the hydrogen absorption surface, C-0, at any time. The fact suggests quasi-equilibrium condition to the absorption-desorption reaction of hydrogen at the surface, and that correlation between C-0 and hydrogen absorption rate. As an analytical result of the transient, a diffusion coefficient decreased with an increase in a content of additional elements, and the decrement was enhanced much more by Cr than by Ni. C-0 was almost proportional to a square root of the cathodic current density at the hydrogen absorption surface for any specimens. The slope increased with an increase in a content of the additional elements, and the increment was enhanced much more by Cr than by Ni. There was a correlation between the slope and the diffusion coefficient, and the correlation suggested that the additional elements of Cr and Ni attract hydrogen. In addition, the attraction effect of Cr was much more than that of Ni. Under anodic potential region, the effect of additional element on C-0 was not clearly obtained in the solution of pH 2, but it is found that C-0 of the Cr-added steel was larger and that of the Ni-added steel was smaller than that of Fe in the solution of pH 6.

DOI： 10.2355/isijinternational.ISIJINT-2015-223

Web of Science

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

Language：Japanese   Publisher：Japan Society of Corrosion Engineering  

Titanium has been selected as the materials for several dental devices because of its excellent mechanical properties, biocompatibility, development of casting process and corrosion resistance to chloride solutions.Besides, fluoride is well utilized as an anticariogenic agent showing the reduction of demineralization, the enhancement of remineralization, the interference of pellicle and plaque formation, the inhibition of microbial growth and metabolism, and others. However, Ti has a nature to dissolve in aqueous fluoride solutions, so that there have been some reports regarding corrosion problem of the titanium dental devices. One of the countermeasure to the problem is to develop a new titanium alloy resistant to corrosion in the fluoride solutions. Therefore, the paper aims to introducing the overview of corrosion behavior of Ti in fluoride solutions and some recent trials to development of new Ti alloys corrosion-resistant to the fluoride solution.

DOI： 10.3323/jcorr.63.309

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：TRANS TECH PUBLICATIONS LTD  

Effect of potential on hydrogen evolution during simulated pitting of aluminum has been investigated. Aluminum wire in 1.0 mm diameter was mounted in resin, immersed in 0.6 kmol.m(-3) NaCl solution and anodically dissolved in axial direction by applying a constant potential from -0.6 to -0.1 V-Ag/AgCl for 86.4 ks. In addition, a resistance of the solution in the crevice of the resin where the aluminum wire corroded was simultaneously measured by superimposing high-frequency alternating potential (Ep-p=10 mV) to the main potential. As higher main potential was applied, the corrosion depth increased. Hydrogen evolved at the corroded site although the anodic potentials were applied. The amount of hydrogen evolution increased as higher main potential was applied to the wire. An interfacial potential (E-int) at just the wire surface was calculated from applied main potential (E-app), solution resistance (R-sol) and current(I) as E-int = E-app - I.R-sol. The interfacial potential was about -0.7 to -1.0 V-Ag/AgCl, and became lower as the higher main potential was applied. The lower interfacial potential may cause hydrogen evolution in this case.

DOI： 10.4028/www.scientific.net/MSF.794-796.107

Web of Science

researchmap

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

We have developed Ti-Mg alloy for dental material corrosion. resistant to aqueous fluoride solutions. Ti plates and granular Mg was put in a sealed vessel and heated at 950 degrees C, so Ti plates were exposed in the liquid and the vapor Mg phases. The conditions made Mg diffuse into the Ti plates to produce Ti. Mg alloy. The Ti. Mg alloy produced in the vapor Mg phase for 430 h achieved homogeneous distribution in Mg concentration of 0.2 at%. A Vickers micro hardness increased almost linearly with an increase in the Mg concentration, and the hardness of the homogeneous Ti-0.2 at%. Mg was about 1.2 times larger than that of Ti before alloying. It was confirmed that corrosion resistance of Ti in the fluoride solution was improved by alloying with Mg. The method using the vapor Mg phase contributed much more effective improvement of corrosion resistance than that using the liquid phase. The homogeneous Ti-0.2 at%. Mg demonstrated a maximum corrosion resistance of all the specimens, by about 80 times to Ti.

DOI： 10.2320/jinstmet.J2013026

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

We have developed Ti-Mg alloy for dental material corrosion-resistant to aqueous fluoride solutions. Ti plates and granular Mg was put in a sealed vessel and heated at 950 degrees C, so Ti plates were exposed in the liquid and the vapor Mg phases. The conditions made Mg diffuse into the Ti plates to produce Ti-Mg alloy. The Ti-Mg alloy produced in the vapor Mg phase for 430 h achieved homogeneous distribution in Mg concentration of 0.2 at%. A Vickers micro hardness increased almost linearly with an increase in the Mg concentration, and the hardness of the homogeneous Ti-0.2at%Mg was about 1.2 times larger than that of Ti before alloying. It was confirmed that corrosion resistance of Ti in the fluoride solution was improved by alloying with Mg. The method using the vapor Mg phase contributed much more effective improvement of corrosion resistance than that using the liquid phase. The homogeneous Ti-0.2 at% Mg demonstrated a maximum corrosion resistance of all the specimens, by about 80 times to Ti.

DOI： 10.2320/matertrans.MC201210

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

Type 304 stainless steel foil was heated to prepare the specimen with coarsegrains whose size was over the foil thickness. Most of grain boundaries (gBs) of the specimen were perpendicular to the surface. The specimen was then sensitized to be subjected to an environment-assisted cracking (eAC) test. Thereafter Σ values of cracking GBs were determined with electron back scattering diffraction (eBSD) method. Most of GBs where cracks were initiated and propagated had a Σ value more than 27, i.e., 'random GB'. The GBs where cracks were initiated had a stress normal to a GB plane (σn) more than 150 MPa and Σ value more than 23. The GBs where cracks propagated had σn more than 10 MPa and Σ value more than 23. The GBs where cracks arrested had two GB characteristics
one was that of Σ value less than 19 and any σn, and the other was that of Σ value more than 19 and σn less than 100 Mpa.

Scopus

researchmap

DOI： 10.2320/jinstmet.76.314

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

We have investigated correlation between grain boundary character and susceptibility to sensitization using SUS304 stainless steel foil with coarse grained structure. The steel foil of 100 mu m thickness was heated at 1473 K for several periods, and a heating time of 604.8 ks was selected to prepare the specimen with coarse grained structure, in which a median of grain size was 229 mu m. In the specimen, most of grain boundary planes were parallel to the thickness direction. The specimen was sensitized and subjected to the grain boundary corrosion test in oxalic acid solution. Thereafter, the orientation of each grain and the Sigma value of each grain boundary were determined by the electron backscattering diffraction (EBSD) method. The corrosion width at the grain boundary positively corresponding to a degree of sensitization increased with an increase in Sigma value, and became stable as the value was more than 19. In addition, the corrosion width at Sigma 3 grain boundary was scattered. Since most of the grain boundary planes were parallel to the thickness direction of the specimen, orientation to each plane of Sigma 3 grain boundary was determined from the EBSD results, and the degree of coincidence for atom sites on the Sigma 3 plane was analyzed. As a result, orientations of the observed Sigma 3 planes were parallel to the common rotation axes characterizing Sigma 3 coincidence site lattice (CSL) in space, and the Sigma 3 grain boundary had three types of planes with different CSL. An area of the unit cell for CSL of the grain boundary plane identified as Sigma 3 was selected as an index of grain boundary character, and an increase in the area correlated to an increase in the corrosion width.

Web of Science

researchmap

Language：Japanese   Publisher：Japan Society of Corrosion Engineering  

We have developed the apparatus for monitoring changes in humidity in the test environment and mass of the rusted steel in order to detect the moisture absorbed into and desorbed out of the steel rust. The rusted steel was set in the container in which the air was controlled to be dry or humid. Change in mass of the rusted steel due to absorption or desorption of moisture was continuously monitored by an electric analytical microbalance, and humidity in the container was spontaneously determined by a digital hygrometer. In the air of a relative humidity (RH) more than 90%, mass of the rusted steel increased rapidly and parabolically due to absorption of moisture into the rust, and then increased gradually and linearly due to adsorption of moisture on the surface. As the test lasted, the mass oscillated ; sudden decrease in mass corresponded to falling a water droplet with some pieces of the rust, and linear increase in mass thereafter did to re-adsorbing moisture. In the case of RH less than 90%, mass change was similar to that of RH more than 90%, but there was no falling of a water droplet from the rusted steel. It is revealed from the long-term test in the air of RH 88% that mass of moisture absorbed into the rust was independent of test time and that mass of new rust increased linearly with test time. In addition, it is suggested that the mass increase rate, that is corrosion rate, corresponds to the cathodic reaction rate limited by diffusion of dissolved oxygen in the thick water film.

DOI： 10.3323/jcorr.61.113

CiNii Books

researchmap

Other Link： https://jlc.jst.go.jp/DN/JALC/10003305774?from=CiNii

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：TRANS TECH PUBLICATIONS LTD  

It has been tried to develop Ti-Ca alloys which demonstrates corrosion resistance in an aqueous fluoride solutions. The Ti-Ca alloys were produced by diffusion-metallizing method A Ti plate and Ca grains were put in a sealed container of stainless steel As the container was heated at 1000 degrees C, Ca was melted and partially vaporized in the inner space Ca then contacts and permeats into the Ti plate to metallize In a holding time of 450 h, the alloy surface consisted of two layers, the first was oxide layer and the second was metal layer of about 200 pm thick. A Vickers micro hardness of the second layer was quite large, upto about 600 Hv. Evaluation of corrosion resistance for the second layer and the inner part was carried out by electrochemical potentiokinetic method. Test solutions were aqueous fluoride solutions produced with HF and NaF. A concentration of fluoride ion was fixed to 0.024 kmol m(-3), and pH of the solution was varied from 3 4 to 4 7. As a result, both Ti and Ti-Ca alloy were passivated under natural immersion condition in the solution of pH 4.7. At pH 3 4, on the other hand, Ti was actively dissolved, but Ti-Ca alloy was still passivated, that means Ti-Ca alloy performs much better corrosion resistance than Ti.

DOI： 10.4028/www.scientific.net/MSF.638-642.564

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：TRANS TECH PUBLICATIONS LTD  

We have investigated the susceptibility to hydrogen embrittlement of interstitial-free (IF) steel with ultrafine-grained microstructure produced by accumulative roll-bonding (ARB) process. The ARB process was conducted to as-received IF steel at 773 K, and repeated to five cycles. The as-received and the ARBed IF steels were cut into tensile specimens, and then hydrogen was electrochemically charged to the specimens in a sulfuric acid solution of pH 2.5 at a cathodic current density of 50 A m(-2) for several charging times. Immediately after the hydrogen-charging process, tensile test was conducted at ambient temperature and an initial strain rate of 3.3 x 10(-4) s(-1). Besides, state and amount of hydrogen absorbed in the specimen were determined with a thermal desorption gas spectroscopy (TDS) at a heating rate of 5.6 x 10(-2) K s(-1). As a result, almost no hydrogen was absorbed in the as-received IF steel charged for a long time of ca. 300 ks, and a fracture strain of the steel was independent of the charging time. On the other hand, amount of hydrogen in the 5-cycle ARBed steel increased with an increase in the charging time, and the fracture strain decreased with an increase in the charging time, indicating that the ARBed steel exhibited susceptibility to hydrogen embrittlement.

DOI： 10.4028/www.scientific.net/MSF.654-656.1235

Web of Science

researchmap

Language：English   Publishing type：Part of collection (book)   Publisher：Elsevier Ltd  

This chapter investigates the influences of potential and pH on environment-assisted cracking behavior (EAC) in order to identify the effects of environmental factors on EAC. EAC tests are conducted with the slow strain rate technique. The material chosen is Ti-6AI-4V. An aqueous solution of Na2SO4 is used for EAC tests. The solution is prepared with distilled water and reagent-grade chemicals. The slow strain rate tensile (SSRT) test equipment SSRT-MINI1000T with a glass cell is employed for the tests. The side and fracture surfaces of specimens are analyzed with a scanning electron microscope. The density of the cathodic current is observed during the EAC test at all potentials except +200 mV, at which the density of anodic current is observed. The current densities are virtually constant throughout the test period, and the density of cathodic current increases with the decrease in potential. Identical trends are observed at pH 3 and 7. At pH 3, the density of the cathodic current increases with decreasing potential. The maximum stress is almost identical to that in air, although it appears to decrease slightly at -300 mV. Therefore, almost no EAC susceptibility is observed at pH 3. Similar trends are observed at pH 7. At pH 1, a unique behavior in maximum stress against potential is observed. © 2008 Elsevier Ltd All rights reserved.

DOI： 10.1016/B978-008044635-6.50034-0

Scopus

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

To investigate the influence of local stress on initiation behavior of stress corrosion cracking (SCC) for sensitized Type 304 stainless steel, cracking process during constant load SCC test was monitored and recorded with an in situ crack observation system. The changes in number of cracks, sum of crack length and cracked area on the specimen surface with test time were identified from the cracking images analyzed by image processing. In the SCC tests, many cracks were initiated and coalesced on the surface, and the coalescence of cracks played an important role to primary crack growth. The influence of applied stress on crack initiation was different from that on crack growth. In addition, there was a difference between influences of stress on incubation period to crack initiation and crack initiation rate. Due to these differences, a stress of 0.8S(y) was thought to cause relatively many cracks compared with 0.5S(y) and 1.3S(y), (S-y = 200 MPa). Through quantitative estimation of distribution in local stress around a crack by finite element analysis method, it was deduced that the crack initiation is influenced not only by bulk stress applied at the end of the body, but also by local stress formed around pre-existing cracks. According to pre-existing cracks, stress enhancement accelerates the crack growth, while the stress relaxation causes the suppression of new crack initiation. Based on the experiment and analysis results, three types of growth process were suggested, which are caused by propagation itself, by new crack initiation at vicinity of the crack tip, and by coalescence of approaching cracks. Then, it was concluded that, in order to predict/simulate the cracking behavior of this SCC system, the influence of local stress on the crack initiation should be taken into account. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.corsci.2007.01.011

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

The high strength Al alloys, 7N01, 6061 and 5083, were examined using slow strain rate testing in chloride-containing acid to neutral solutions under potentiostatic control. Large amounts of hydrogen absorption occurred at potentials above the breakdown potential. In this potential range, the mechanical strength of the alloys is degraded manly by severe general corrosion but hydrogen embrittlement may also occur. On the other hand, polarisation at more negative potentials where there is intense hydrogen evolution does not necessarily lead to a large amount of hydrogen entry except for the case of the alloy 5083, which suffered from hydrogen embrittlement induced by hydride formation around precipitates. copyright The Electrochemical Society.

DOI： 10.1149/1.2789226

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

To investigate the initiation behavior of stress corrosion cracking (SCC) for sensitized Type 304 stainless steel in high temperature water, a constant load SCC test method combined with in situ crack observation technique was employed. The in situ crack observation system allowed us to detect small cracks of at least 100 mu m. As a result, a fracture time decreased with an increase in an applied stress. The first cracks were observed at most 3 h before the specimen was fractured under all the stress conditions. After that, many cracks were initiated in a short time to fracture. The fracture was caused by coalescence of multiple cracks rather than by growth of some primary cracks. The simulation model for surface crack initiation was newly developed using a Monte Carlo method, which was based on damage mechanics and stress analysis around the existing cracks. The simulation could represent the empirical results of changes in the crack distribution and the cumulative number of cracks during the SCC tests. It was concluded, therefore, that the crack initiation process should be considered in simulating the life prediction of the material in this SCC system. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.corsci.2005.09.015

Web of Science

researchmap

researchmap

DOI： 10.1016/j.corsci.2004.10.011

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

We have investigated the influences of potential and pH on environment-assisted cracking (EAC) of Ti-6Al-4V in aqueous solutions. The EAC test was conducted by slow strain rate technique. Solution pH was controlled from I to 7, and applied potential was fixed between -1.8 and +0.2 V-SHE. In the solutions of pHs 3 and 7. mechanical properties of the material was almost independent of applied potential. This means that the material shows almost no EAC susceptibility in the potential-pH region for the EAC test period. At pH 1, however, both maximum stress and fracture strain changed with applied potential, and showed minimum values at an applied potential of about -1.0 V-SHE. According to surface analyses by scanning electron microscopy and X-ray diffraction technique, some cracks and Ti hydride were detected from only the specimens fractured at about -1.0 V-SHE in the solution of pH 1. Therefore, it can be concluded that Ti-6Al-4V is most susceptible to the EAC at about -1.0 V-SHE and a pH less than 1. The EAC region was in good agreement with Ti ion stable region in a potential-pH diagram of Ti/water system, and was quite similar to that on the EAC of TiAl.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Inhibition effect of metal cation to intergranular stress corrosion cracking (TGSCC) of sensitized Type 304 stainless steel has been investigated by slow strain rate technique (SSRT) with a dynamic crack observation system. The SCC tests were conducted in fully-deaerated aqueous solutions containing various metal sulfates of 10(-5) kmol/m(3) at 95 degrees C. Metal cations of Na+, Ca2+ Mn2+ and Zn2+ were selected in this study, and were characterized by a hardness based on the hard and soft acids and bases (HSAB) concept. As a result, it was found that a hard metal cation in the test solution increased crack initiation time and decreased mean crack initiation frequency. In other words, metal cations with larger hardness have an ability of suppressing initiation process of the IGSCC. On the other hand, apparent mean crack velocity was independent of the hardness of metal cation. The finding that the metal cations with large hardness inhibit initiation of the IGSCC was able to be rationally explained on the basis of the passive film model combined with the HSAB concept. (c) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.corsci.2004.06.014

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ASSOC CORROSION ENG  

A slow strain rate testing apparatus equipped with an autoclave as well as with an in-situ crack observation system has been newly developed. Using this system, the growth behavior of multiple cracks in high-temperature water up to about 300 degreesC could be observed in-situ. In this study, the initiation and propagation of stress corrosion cracks in sensitized Type 304 (UNS S30400) stainless steel immersed in 10(-4) kmol/ m(3) sodium sulfate (Na2SO4) solution from 100 degreesC to 250 degreesC were investigated. It was found that stress corrosion cracking (SCC) susceptibility evaluated from the time to fracture increased with an increase in temperature. The in-situ observations of the cracks revealed the following:
-The time to initiate the first crack decreased with art increase in temperature.
-The cumulative number of cracks increased almost linearly with deformation time at any temperature.
-Both the final number of cracks and the crack initiation frequency exhibited a maximum at 150 degreesC.
-The distribution in the crack propagation rates was found to fit the Weibull probability distribution. The mean crack propagation rate increased with an increase in temperature according to the Arrhenius relation with an estimated activation energy of about 2.1 kcal/mol.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

A Scanning Laser-Enhanced Electrochemical Microscope for Hydrogen detection (H-SLEEM) has been developed in order to in-situ visualize the distribution of hydrogen localized on a steel surface. Introduction and detection of hydrogen for the steel sheet was conducted by hydrogen permeation technique with a pair of electrochemical cells. When the hydrogen detection side under hydrogen permeation is irradiated with focused Ar laser, anodic current relating to hydrogen oxidation reaction is thermally enhanced at the irradiation spot and then anodic current Increment corresponding to the hydrogen permeation rate at the spot is expected to be determined. In the case that whole the hydrogen detection side was irradiated with diffused laser, the anodic current increased and the current increment increased with an increase in the hydrogen permeation current. The use of focused laser also permitted the measurement of the anodic current increment depending on the hydrogen permeation current. The modulated laser provided more stable and reproducible current increment. When the specimen whose hydrogen entry side was masked except for a small exposed area in center was employed and the modulated laser was raster-scanned under hydrogen permeation, a very clear image of the two-dimensional distribution in the current increment corresponding to local hydrogen permeation rate on the detection side was obtained. It is concluded that the H-SLEEM can successfully visualize the localized hydrogen distribution on the steel surface.

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MINERALS, METALS & MATERIALS SOC  

In previous work, we had investigated environment-assisted cracking (EAC) behavior of gamma-TiAl in 0.05 M sulfate solutions as functions of pH and potential by using slow strain rate tensile test, and plotted the EAC susceptibility in the potential-pH diagram of Ti-H2O and Al-H2O Systems. From the results, we had revealed that the EAC susceptibility was in distinct agreement with the diagram of Ti-H2O system, and especially severe EAC susceptibility located in Ti ion (i.e., Ti2+, Ti3+) stable region. In this work, we have extensively investigated the effect of strain rate in the range from 10(-3) to 10(-7) s(-1) on the EAC susceptibility of the material in the same solution of pH 3. At Ti oxide stable potential of +200 mV, the EAC susceptibility was almost independent of the strain rate, similar to that under vacuum condition. While, the susceptibility was found to increase with lowering the strain rate at Ti hydride stable potential of -2000 mV. At Ti ion stable potential of -1250 mV, tendency of EAC susceptibility with strain rate was similar to that at -2000 mV. However, a decrease in the susceptibility was found at the slowest strain rate. Xray diffraction method indicated that the additional peak relating to hydride presence at -1250 mV, although only a substrate TiAl peak was found at -200 mV. At -2000 mV, no hydride peak over the strain rate range was evident except for the slowest strain rate. The intensity of the hydride peak increased with lowering the strain rate except for the lowest strain rate where the intensity goes down at -1250 mV. At -2000 mV, on the other band, the susceptibility decreased with a decrease in the strain rate, even where no hydride detected by a conventional system. It is concluded that the very thin hydride may induce the EAC of the material, and the susceptibility increases with the increase in the amount of hydride.

Web of Science

researchmap

DOI： 10.1016/S0010-938X(03)00031-3

researchmap

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

We have investigated the effect of sulfate ion on corrosion behavior of SM 400 B carbon steel in carbonate/bicarbonate solutions at 343 K by using a conventional potentiokinetic method with potential scan rate of 0.1 mV·s-1. In the solution containing sulfate less than 0.001 kmol·m-3, there are two active anode peaks and passive region. Addition of sulfate more than 1.0 kmol·m-3 gave cathodic current between the two active peaks and lowered pitting potential. The active peak current density at lower potential increased linearly with increase in equilibrium concentration of bicarbonate. This suggests to result from the formation of iron complex with bicarbonate ion for the active dissolution of iron. Cathodic polarization curves of Pt in the test solution showed that the increase in the concentration of sulfate led to the linear increase in cathodic current around the potential between two active peaks. Accordingly, it is concluded that sulfate ion can act as oxidant against the natural corrosion of the steel in this environment. Pitting potential of the steel was lowered with increase in the concentration of sulfate in concentrated region. In the same concentration of sulfate, the pitting potential increase with increase in pH. The trend suggests the retardation of the pitting is due to the solution properties of high pH and high buffer capacity.

DOI： 10.3323/jcorr1991.51.350

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Environment-assisted cracking (EAC) of γ-TiAl has been investigated from electrochemical viewpoint. The TiAl was forged at 1373 K and annealed at 1073 K for 7.2 ks. The specimen whose potential was controlled was tested in aqueous sulfate solutions of various pHs at room temperature by using a slow strain rate tensile testing apparatus. The experimental EAC results evaluated by the maximum stress was discussed on the basis of the potential-pH diagram of Al and Ti/water system. It was revealed that the diagram of Ti/water system can predict the EAC susceptibility of TiAl, although the diagram of Al/water system shows almost no relation to the susceptibility. The results suggest that the EAC of TiAl is controlled by the stability of Ti oxide, hydride, and ion on the solution/substrate interface, which affect the entry of hydrogen into the material. © 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-5093(01)01654-9

Scopus

researchmap

Language：English   Publishing type：Research paper (other academic)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

The effect of irradiation of ultra-violet(UV) light on stress corrosion cracking(SCC) behavior for sensitized SUS304 stainless steel in a deaerated 10(-3) kmol.m(-3) NaCl solution at 368 K has been investigated by using a slow strain rate testing(SSRT) apparatus with a dynamic observation system. The UV light, whose range of wavelength was from 250 to 400 nm, was emitted by a mercury lamp, and was irradiated to the specimen through the test solution. In order to change an intensity of the UV light, some neutral density filters were set in front of the quartz glass window on the cell. A potential of -200 mV(Ag/AgCL) was applied to the specimen before and during SSRT, and the UV light was irradiated up to the strain showing almost the yield stress. It was obvious that the SCC initiation was inhibited by the UV light irradiation to the specimen during SSRT. Crack initiation frequency varied with the light intensity, and an optimum intensity range existed for inhibiting crack initiation completely. On the other hand, the crack propagation rate showed almost no dependence on the irradiation conditions. In the case that the UV light was irradiated to the shielding material mounted in front of the specimen, a lot of cracks were initiated on the specimen, similar to the case without irradiation. This fact indicates that the SCC is not influenced by the solution chemistry altered by the UV light irradiation.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Environment-assisted cracking (EAC) of gamma-TiAl has been investigated from electrochemical viewpoint. The material whose potential was controlled was tested in aqueous sulfate solutions of various pHs at room temperature by using a slow strain rate tensile testing apparatus. The TiAl forged at 1373 K and annealed at 1073 K for 7.2 ks was used in the EAC test. It was found in the alkaline and the natural solution that maximum stress was independent of the potential in higher potential region, and decreased with decrease in the potential in the lower potential region. In acidic solution, the maximum stress changed with the potential as follows; the maximum stress was independent of the potential above -200 mV(SHE), decreased with decrease in the potential between -200 and -1000 mV(SHE), and increased with decrease in the potential below -1000 mV(SHE). The experimental EAC results was discussed on the basis of the potential-pH diagram of Al and Ti/water system. It was revealed that the diagram of Ti/water system can predict the EAC susceptibility of TiAl, although the diagram of Al/water system shows almost no relation to the susceptibility. Therefore, the EAC of TiAl is controlled by the stability of Ti oxide, hydride, and ion on the solution/base material interface, which affect the entry of hydrogen into the material. (C) 2000 Elsevier Science Ltd. All rights reserved.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The effect of concentration and type of anions on stress corrosion cracking of sensitized type 304 stainless steel was investigated by slow strain rate test (SSRT) with a dynamic cracking observation system. It was found that difference of anion type added into pure water exerted a significant effect on crack initiation time and mean crack initiation frequency. Some anions, such as OH- and B4O72-, can suppress, while others, such as S2O32- and SO42-, accelerate crack initiation. The effect of anion type on the crack initiation behavior was explained on the basis of the passive film model proposed by Okamoto and Shibata and a HSAB (hard and soft acids and bases) concept. The anion having a larger hardness value was found to show a longer crack initiation time or to delay the crack initiation. The anion with a larger hardness, that is expected to show a stronger affinity to proton, is considered to accelerate deprotonization, and to enhance the repassivation process. Consequently, the harder anion is expected to induce a more perfect passive film more rapidly, and then to retard the crack initiation more effectively. (C) 2000 Elsevier Science Ltd. All rights reserved.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：E D P SCIENCES  

The crack initiation and propagation behavior of a sensitized Type 304 stainless steel in distilled water containing small amounts of Na2SO4 or Na2B4O7 impurities was investigated by using slow strain rate technique (SSRT) with an insitu cracking observation system, and analyzed with a statistical approach. It was found that the crack initiation time for the steel in Na2SO4 or Na2B4O7 solutions obeyed the exponential distribution, while K-ISCC and crack velocity obeyed the Weibull distribution. An increase in Na2B4O7 concentration decreased the SCC susceptibility of the steel by delaying crack initiation time, reducing the crack initiation rate and increasing K-ISCC. In contrast, an increase in Na2SO4 concentration increased SCC susceptibility of the steel by shortening crack initiation time and accelerating crack propagation.

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Soc of Corrosion Engineering  

Effects of annealing conditions on stress corrosion cracking (SCC) of SM 400 B carbon steel has been investigated in 1 M sodium bicarbonate solution at 343 K. A potentiostatic slow strain rate test equipped with a charge coupled device camera system was employed to evaluate SCC susceptibility from the viewpoint of the crack behavior. Fixing an annealing time of 3.6 ks, no SCC appeared on the specimens annealed below 973 K, but intergranular SCC occurred beyond 1073 K. In the case that the SCC occurred, an increase in annealing temperature led to a decrease in crack initiation time and an increase in crack propagation rate. Fixing an annealing temperature of 1173 K, it is found that the SCC occurred in the annealing time range from 0.6 to 86.4 ks and that the fracture strain showed maximum at 3.6 ks. Analyzing the crack behavior, crack initiation time and crack propagation rate were found to be maximum and minimum at 3.6 ks, respectively. Thus, it was concluded that the maximum fracture strain at 3.6 ks resulted from minimum SCC susceptibility evaluated by initiation as well as propagation of the cracks. On the other hand, the observation of microstructure of the specimen revealed that the specimen surface suffered from decarburization during the annealing treatment beyond 1073 K, and the SCC always occurred on the specimen showing the decarburized structure.

DOI： 10.3323/jcorr1991.49.138

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Soc of Corrosion Engineering  

Effects of potential and concentration of bicarbonate on stress corrosion cracking of annealed SM 400 B carbon steel has been investigated in bicarbonate solutions at 343 K. The surface of annealed specimen had decarburized layer of about 0.5 mm thickness. A potentiostatic slow strain rate testing apparatus equipped with a charge coupled device camera system was employed to evaluate SCC susceptibility from the viewpoint of the crack behavior. In a constant bicarbonate concentration of 1 M, cracks were observed in the potential range from -800 to 600 mVAg/AgCl, and especially, the initiation and the propagation of the cracks were accelerated at -600 mV. At a constant potential of -600 mV, cracks were observed in the concentration range from 0.001 to 1 M, and the initiation and the propagation of the cracks were suppressed as the concentration decreased. Polarization curves for the decarburized surface were measured with two different scan rates. High SCC susceptibility may be expected in the potential range where the difference between the two current densities is large. It was found in this system that the potential with the maximum difference in the current density was -600 mV for 1 M bicarbonate solution, and the potential increased with a decrease in the concentration of bicarbonate. This means that an applied potential of -600 mV provides the highest SCC susceptibility for 1 M bicarbonate solution, and that the SCC susceptibility decreases as the concentration decreases. These findings support the dependence of the actual SCC behavior on the potential and the concentration of bicarbonate.

DOI： 10.3323/jcorr1991.49.144

Scopus

researchmap

Language：English   Publishing type：Research paper (other academic)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

Effect of irradiation by ultra-violet (UV) light on stress corrosion cracking (SCC) of sensitized SUS304 stainless steel in a deaerated 10(-3) kmol.m(-3) NaCl solution has been investigated by using a slow strain rate testing (SSRT) apparatus with a dynamic observation system. The SCC initiation was inhibited by the UV light irradiation to the specimen during SSRT. Change in the light intensity led to the change in crack initiation frequency. The maximum inhibition effect was observed at an optimum intensity. However, crack propagation rate showed almost no significant dependence on any irradiation conditions.

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

Environment-assisted cracking (EAC) of Ti in methanol solutions containing various concentrations of CaCl2 has been investigated by using a slow strain rate testing (SSRT) apparatus with dynamic observation system. In the EAC test, water content in the solutions was strictly controlled and the test solution was fully deaerated. Like the case of HCl addition, it was observed that cracks were initiated from black pits generating during the test and that the cracking mode was intergranular at the initial stage and transgranular at the final stage of the crack propagation. Under open circuit condition, cracking occurred only at 0.02 and 0.2 kmol.m(-3) CaCl2 and the maximum corrosion potentials when cracking occurred, which means the critical potential for EAC, was a negative function of the logarithm of the chloride concentration. The potentiostatic SSRT confirmed the linear relationship between the critical potential and logarithm of chloride concentration in the chloride concentration range from 4 x 10(-4) to 4 x 10(-2) kmol.m(-3). In comparison with the case of HCl addition, CaCl2 addition provided the same slope of the relation but higher critical potential. It was also found that the dissolved oxygen plays a role of increasing corrosion potential as an oxidant, and that the cracking occurs when the corrosion potential exceeds the critical value for EAC. It is concluded that the EAC initiation of this system is controlled by the mechanism of initiation of anodic localized corrosion by chloride ions.

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

Environment-assisted Cracking (EAC) of Ti in methanol solutions containing various concentrations of HCl has been investigated by using a slow strain rate testing apparatus with a dynamic observation system. In the EAC test, dissolved oxygen and water content were strictly controlled because it is known that these two factors influence the cracking of this system. It was observed that cracks initiated from black pits which were generated during the test, and that the cracking mode was intergranular and transgranular at the initial and the final stage of the crack propagation, respectively. Cracking occurred at 0.004 to 0.04 and 0.0004 to 0.04 kmol.m(-3) HCl for initial strain rates of 8.3 x 10(-7) and 2.5 x 10(-6) s(-1), respectively. This behavior was also influenced by electrode potential, that is, the cracking occurred above a critical potential depending on the concentration of HCl. The critical potential was expressed as a negative function of a logarithm of the concentration of HCl, and the potential was lowered as the initial strain rate increased. It was concluded that initiation of EAC for this system is mainly controlled by an anodic localized corrosion mechanism.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ASSN CORROSION ENG  

The effects of solution pH and buffer capacity on intergranular stress corrosion cracking (IGSCC) of sensitized type 304 stainless steel ([SS] UNS S30400) was examined at 95 degrees C by slow strain rate technique (SSRT) with an in-situ cracking observation system, It was found that an increase in solution pH or buffer capacity increased crack initiation time and decreased mean crack initiation frequency, but exerted almost no effect on crack propagation. This inhibition effect on IGSCC initiation was explained as resulting from a retarding effect of solution pH and buffer capacity on the decrease in pH at crack nuclei caused by the hydrolysis of metal ions dissolved when the passive film was ruptured by strain in SSRT.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The stress corrosion cracking (SCC) of sensitized Type 304 stainless steel has been examined in Na2B4O7 + Na2SO4 solutions with a constant solution conductivity by using the slow strain rate test (SSRT). The cracking behavior was observed in-situ by a dynamic observation system with a charge-coupled device (CCD) camera. It was found that an increase in the k (= [Na2B4O7]/[Na2SO4]) value, or borate concentration, leads to a decrease in the SCC susceptibility by retarding crack initiation, namely, by delaying crack initiation time and reducing crack initiation frequency. By contrast, an increase in sulfate concentration enhances SCC susceptibility by shortening crack initiation time and accelerating crack initiation frequency. The critical sulfate concentration to accelerate crack initiation is 10(-5) kmol/m(3) and, below this concentration, the suppressing effect of borate ions on the SCC works. In addition, it is the solution conductivity, rather than the anion type or their concentrations, which control crack propagation. (C) 1999 Elsevier Science Ltd. All rights reserved.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ASSN CORROSION ENG  

The intergranular stress corrosion cracking (IGSCC) behavior of sensitized type 304 (UNS S30400) stainless steel (SS) in dilute sodium borate (Na2B4O7) solutions at 95 degrees C was examined by slow strain rate testing (SSRT) using a dynamic observation system. The borate ion (B4O72-) suppressed IGSCC susceptibility of sensitized type 303 SS by delaying the crack initiation time and reducing the crack initiation frequency (CIF). The inhibition effect of the borate ion (B4O72-) on crack initiation may have resulted from its buffer effect on local acidification at crack nuclei and its inhibitive nature in reacting with metal ions to form a protective film. However, B4O72- concentration provided no remarkable inhibition effect on crack velocity (CV), which depended mainly upon solution conductivity, within the scattered values. Hydroxyl ions (OH-) also suppressed initiation of IGSCC, but not as effectively as B4O72-. The crack initiation time obeyed the exponential probability distribution, and the CV obeyed the Weibull probability distribution.

Web of Science

researchmap

Language：Japanese  

DOI： 10.3323/jcorr1991.47.267

CiNii Books

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

Electrochemical behavior and environment-induced degradation in strength for a carbon steel, SM400B, have been investigated in 0.025 M Na2CO3 + 0.075 M NaHCO3 solutions containing various concentrations of NaCl at 363 K. A slow strain rate test (SSRT) was employed to evaluate the degradation in mechanical properties. It was found from polarization curves that there generated pitting corrosion beyond 0.01 M NaCl. The SSRT was carried out applying a potential below the pitting potential to the specimen in the test solutions containing 0.5 and 0.01 M NaCl. Under both solution conditions, an increase in the applied potential resulted in a reduction in maximum stress and fracture strain, as well as an increase in current density during SSRT. From observation of the surface of the fracture specimens, however, there was no crack on it. Based on assumption of homogeneous deformation and general dissolution until maximum load, true stress at the maximum load was calculated. It was revealed that the true stress was almost independent of the applied potential, although the maximum load decreased with increase in the applied potential. It means that the homogeneous dissolution is accelerated by applying the stress and/or the dynamic strain. It is concluded from the facts that the degradation in the mechanical properties results from a rapid reduction in the cross section due to homogeneous dissolution, instead of localized corrosion.

DOI： 10.3323/jcorr1991.47.771

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Initiation and propagation of IGSCC for sensitized Type 304 stainless steel in dilute sulfate solutions have been investigated by the slow strain rate test (SSRT) with a CCD camera system. An increase in concentration of sulfate ion was found to cause decrease in crack initiation strain and fracture strain, resulting in the increase in the IGSCC susceptibility. Statistical analysis made it clear that the increase in concentration of sulfate ion had little effect on crack initiation frequency, and crack initiation time obeyed the exponential probability distribution, but the crack velocity obeyed the Weibull probability distribution. With increase in the concentration of sulfate ion, the crack velocity increased, and the number of cracks decreased. On the contrary, the mean crack velocity decreased and the number of cracks increased with time. The dependence of the crack velocity on the concentration of sulfate ion and the number of active cracks under potentiostatic SSRT conditions was successfully explained by a multiple cracks model combined with the mass transport model. (C) 1997 Elsevier Science Ltd.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELECTROCHEMICAL SOC INC  

The point defect model (PDM) has been used to derive the dependence of the pitting potential on the voltage scan rate. Relationships derived from the PDR? predict that the observed pitting potential is a linear function of the square root of voltage scan rate at low scan rates, which agrees with experimental data reported in the literature. Furthermore, the critical concentration of condensed cation vacancies that give rise to passivity breakdown. as estimated from the sweep rate dependence of the pitting potential, is found to be in good agreement with that estimated from structural considerations. The PDM is also used to predict the probability distribution function in the induction time for pitting (t(ind)), that is, the survival probability, by assuming that the maximum diffusivity of the cation vacancy in a population of specimens is log-normally distributed. This calculated ''external'' distribution in the induction time is found to be in reasonable agreement with experimental induction time data for passivity breakdown on multiple specimens of single cn-stal (100) Ni and polycrystalline nickel buffered chloride solutions.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

The stress corrosion cracking (SCC) of Type 304L stainless steel in chloride solutions containing various concentrations of thiosulfate ions (S2O3 2-) has been studied by using a slow strain rate testing apparatus with a dynamic observation system. It was observed that intergranular cracks were initiated from pits and propagated with the evolution of bubbles. The SCC was found to occur &gt
10-3 M S2O3 2-, and the variation in the concentration of S2O3 2- from 10-3 to 10-1 M did not shown any marked difference in SCC susceptibility evaluated by maximum stress. According to the analysis of the cracking behavior from the observed images, crack propagation rate was found to increase slightly with increase in the concentration of S2O3 2-. The increase is considered to be caused by the change in the corrosion potential with the concentration. Apparent critical stress intensity factor for SCC was less scattered around 2-3 MNm-3/2 and slightly increased with increase in the concentration. The strain where either a pit or a crack was initiated first and the number of pits and cracks decreased remarkably and increased with increase in the concentration, respectively. S2O3 2- mainly affects the initiation process of the pit and the crack more than the crack propagation process. © 1997 Elsevier Science Ltd.

DOI： 10.1016/S0010-938X(97)00087-5

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

The stress corrosion cracking (SCC) of Type 304L stainless steel in chloride solutions containing various concentrations of thiosulfate ions (S2O3 2-) has been studied by using a slow strain rate testing apparatus with a dynamic observation system. It was observed that intergranular cracks were initiated from pits and propagated with the evolution of bubbles. The SCC was found to occur &gt
10-3 M S2O3 2-, and the variation in the concentration of S2O3 2- from 10-3 to 10-1 M did not shown any marked difference in SCC susceptibility evaluated by maximum stress. According to the analysis of the cracking behavior from the observed images, crack propagation rate was found to increase slightly with increase in the concentration of S2O3 2-. The increase is considered to be caused by the change in the corrosion potential with the concentration. Apparent critical stress intensity factor for SCC was less scattered around 2-3 MNm-3/2 and slightly increased with increase in the concentration. The strain where either a pit or a crack was initiated first and the number of pits and cracks decreased remarkably and increased with increase in the concentration, respectively. S2O3 2- mainly affects the initiation process of the pit and the crack more than the crack propagation process. © 1997 Elsevier Science Ltd.

DOI： 10.1016/S0010-938X(97)00087-5

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：TRANS TECH PUBLICATIONS LTD  

Although grain boundary sliding (GBS) mainly contributes to superplastic deformation, there are few studies on GBS behavior at each boundary in superplastic materials. It has been investigated the effect of three grain boundary characters of the angle between grain boundary at the specimen surface and the tensile direction, the kind of adjacent grains across a grain boundary, and Sigma value which was calculated from orientations of adjacent grains across a grain boundary on GBS in a superplastic Pb-Sn alloy.
The superplastic behavior is found when GBS takes place at most of grain boundaries. It is considered that GBS is easier at a grain boundary both with the higher angle between grain boundary and tensile direction, and with the same kind of adjacent grains across a grain boundary. GBS is more difficult to occur at grain boundaries with rather low Sigma value than at random grain boundary. It is also shown that, for random grain boundary, GBS is easier to occur at a grain boundary with higher angle.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

The effect of crystallization on the stochastic pit generation process of an Fe-Cr-Si-B amorphous alloy in a berate solution containing Cl- ions has been analyzed. Fitting potential of amorphous alloys showed a wide scatter and mean value shifts to the noble direction before crystallization starts, decreasing rapidly after crystallization, Stochastic analysis demonstrates that the initial increase in pitting potential is brought about by an increase in the pit repassivation rate, while the decrease in pitting potential after crystallization is caused by a rapid increase in the pit generation rate. Silicon oxide film formation during the heat treatment is concluded to be the main reason to increase the pitting potential and alpha-Fe micro-crystallites by crystallization in the latter stage of the heat treatment are responsible to decrease the pitting potential.

Web of Science

researchmap

Language：Japanese   Publisher：Japan Society of Corrosion Engineering  

The effects of potential and sodium sulfate concentration on the initiation and growth of IGSCC of sensitized 304 stainless steel in 0.01-1kmol/m³ sodium sulfate solutions at 368K have been investigated. A slow strain rate test apparatus was used to make direct observations of crack generation and propagation during the test. The initiation and growth of IGSCC were found to occur for potentials from -500mV_Ag/AgCl to -200mV_Ag/AgCl and the IGSCC susceptibility reached a maximum at approximately from -400mV_Ag/AgCl to -300mV_Ag/AgCl. The initial crack generation time was a minimum around -400mV_Ag/AgCl and the crack growth rate increased monotonously with increasing potential. Therefore, the SCC test results indicated that the maximum IGSCC susceptibility emerged at approximately from -400mV_Ag/AgCl to -300mV_Ag/AgCl, suggesting that the susceptibility of IGSCC must be determined as a function of the synergistic effect of the crack generation frequency and the crack growth rate. The initial crack generation time decreased with increasing sodium sulfate concentration. The crack growth rate was independent of the crack generation time and showed approximately a constant value. The crack generation time were distributed at random. Therefore, it was considered indispensable to evaluate IGSCC resistance of various austenitic stainless steel by statistical methods.

DOI： 10.3323/jcorr1991.44.343

CiNii Books

researchmap

Other Link： https://jlc.jst.go.jp/DN/JALC/00033423074?from=CiNii

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

The amount of defects in TiN films coated on SUS 304 stainless steel has been evaluated by three electrochemical measuring techniques in a sulfuric acid solution containing potassium thiocyanate. Three different TiN films were prepared by a hollow cathode ion plating technique. A critical passivation current density (i(crit)) can readily provide the apparent amount of the defects. However, this method was found to overestimate the amount of the defects because active dissolution of the substrate at the measurement caused enlargement of the defects. An activation time, which is a period until free corrosion potential (E(corr)) descends to that of the bare substrate steel, was not useful to evaluate the amount of defects rapid ly because about a half the specimens did not activate within a test time of 90 ks. More precise and less destructive evaluation could be achieved by using a reciprocal of polarization resistance (R(p)(-1)) which was obtained by an electrochemical impedance spectroscopy immediately after activation. It is concluded that i(crit) is a suitable parameter for an approximate estimation of the defect area, and R(p)(-1) provides the more precise amount of the original defects.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ASSN CORROSION ENG  

The initiation and growth of cracks in type 316L (UNS S31603) stainless steel (SS) in a chloride solution containing thiosulfate ions (S2O32-) during slow strain rate testing (SSRT) were analyzed on the basis of fracture mechanics. Crack behavior on the specimen surface was observed in situ using a charge-coupled device (CCD) camera with a videotape recording system. Three types of specimens were used: a single-notched plate, a smooth cylinder, and a smooth plate. The single-notched specimen failed to produce a sharp crack similar to that formed on the smooth specimens. For the smooth specimens, the stress intensify factor (K-ISCC) was found to vary from 3.9 MN/m(3/2) to 5.0 MN/m(3/2), and the crack growth rate ranged from 5.2 x 10(-9) m/s to 1.0 x 10(-8) m/s, which approximately agreed with data determined by other authors using a fracture mechanics approach. Thus, the SSRT combined with the in situ observation technique was useful in analyzing the crack initiation and growth process.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Polarization curves of Fe, Ni, Cr, Ni-18 mass% Cr alloy and Type 304 stainless steel were measured in aqueous fluoride solutions of various pH values from 1.9 to 11.7 at 303K. The concentration of fluoride ion was fixed at 0.2kmol·m-3 for all the solutions. Fe shows the very large current density of 101 to 102 A·m-2 beyond-500mVAg/AgCl at pH≤8.2 and beyond-100mV Ag/AgCl at pH 11.7. Ni shows the large current density beyond-200mV Ag/AgCl at pH≤3.2. However, two peaks appear in the curves at pH 5.8 and 8.2, and a passive region has the very small current density of 10-1 to 10-2 A·m-2 at pH 11.7. Cr does not show any active region but a passive region with the very small current density at any pH values. Ni-18 mass% Cr alloy shows that the current density increases with increasing potential at pH≤8.2, and that a passive region with very small current density appears at pH 11.7. Type 304 stainless steel behaves similarly as Cr such that they have very small current densities in the passive region at any pH values. No localized corrosion such as pit was found for all the materials. © 1994, Japan Society of Corrosion Engineering. All rights reserved.

DOI： 10.3323/jcorr1991.43.331

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

The effects of temperature and applied potential on the intergranular stress corrosion cracking, IGSCC, susceptibility of sensitized SUS304 stainless steel in NaF aqueous solution have been investigated by using slow strain rate test, SSRT, based on the direct observation of crack generation and propagation during the test. It was found that the decrease in the maximum stress, which is usually used as a conventional SCC susceptibility index by SSRT, with increasing temperature was caused not only by the decrease in K'(ISCC), and crack generation time but also by the increase in crack growth rate and the number of cracks. The result of potential-controlled SSRT proved that the lowest maximum stress at 100 MV(Ag/AgCl) was induced by the decrease in K'(ISCC) and crack generation time. In conclusion, crack generation is more important compared with crack propagation for deciding the IGSCC susceptibility of sensitized SUS304 stainless steel in NaF solution.

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Using a slow strain rate technique, SSRT, with CCD camera system, initiation and growth behavior of intergranular stress corrosion cracking, IGSCC, for sensitized 304 stainless steel in aqueous solution containing various concentrations of NaF has been investigated. The largest decrease in maximum stress indicating the highest IGSCC susceptibility was found at 10(3) ppm NaF. And at the same concentration of 10(3) ppm NaF, the highest density of crack number and the shortest crack generation time was found. On the other hand, threshold stress intensity factor for IGSCC was independent of concentration of NaF. Crack growth rate showed a little dependence on NaF concentration, exhibiting a decrease at 10(3) ppm. It was obvious from the results that the highest IGSCC susceptibility at 10(3) ppm NaF was caused by increasing the number of cracks and decreasing the crack generation time, not by a change in threshold stress intensity factor for SCC or crack growth rate.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ASSN CORROSION ENG  

Thiosulfate ion was used as a substitute for hydrogen sulfide (H2S) to simulate stress corrosion cracking (SCC) of corrosion-resistant alloys (CRAs) and sulfide stress cracking (SSC) of high-strength, low-alloy steels. Several SCC tests using a variety of stress application techniques showed the brine containing thiosulfate exhibited similar severity to brine containing H2S in regard to SCC when plastic strain was applied to the CRAs. Materials that exhibited SCC susceptibility in brine containing thiosulfate agreed well the SCC susceptibility of those in brine containing H2S. Types 304 (UNS S30400) and 316L (UNS S31603) stainless steels and duplex stainless steel exhibited in both environments. However, high-nickel austenitic alloys such as alloys 904L (UNS N08904) and 825 (UNS N08825) did not. A 10(-3) to 10(-2) mol/l S2O32- addition in 20% NaCl aqueous solution at 353 K corresponded to H2S of 0.1 to 1 MPa at 473 K. The SSC susceptibilities of high-strength, low-alloy steels in a 10(-3) mol/l S2O32- + 5% NaCl + 0.5% acetic acid solutions were close to those in NACE Standard TM0284-86 solution (substitute ocean water saturated with 0.1 MPa H2S). Results suggested the possibility of using thiosulfate ion as an alternative to H2S.

Web of Science

researchmap

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN INST METALS  

It is well known that grain boundary sliding (GBS) mainly contributes to superplastic deformation. However, since there are few studies on GBS behavior at each grain boundary during superplastic deformation by using polycrystal material, the contribution of three grain boundary characters to GBS at each grain boundary during superplastic deformation has been investigated. Three characters were adopted as the following; the angle between grain boundary at the specimen surface and tensile direction, the kind of adjacent grains across a grain boundary, and SIGMA-value which was calculated from orientations of adjacent grains across a grain boundary. The examination was carried out by tensile test in SEM with Pb-Sn eutectic alloy at room temperature. The results obtained are summarized as follows: (1) The superplastic behavior was confirmed to occur when GBS was observed at most of grain boundaries. (2) It is considered that GBS is easier at a grain boundary both with the higher angle between grain boundary and tensile direction, and with the same kind of adjacent grains across a grain boundary. (3) So far as Pb-Pb boundary is concerned, GBS was more difficult to occur at grain boundary with rather low SIGMA-value than at random grain boundary. Moreover, for random grain boundary, GBS was easier to occur at a grain boundary with higher angle of grain boundary.

Web of Science

researchmap

DOI： 10.3323/jcorr1991.41.217

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Susceptible potential region for stress corrosion cracking, SCC, of SUS316L stainless steel has been investigated in 20 mass % NaCl aqueous solution containing 10(-2) kmol.m-3 thiosulfate ion by using a slow strain rate technique, SSRT. Potential from -400 to -340 mV(Ag/AgCl) was controlled either chemically by changing the concentration of dissolved oxygen, DO, in the solution or electrochemically by using a potentiostat. In both cases, cracks always generated at pits. In case of controlling DO, free corrosion potential raised and a shape of pit and crack changed with increase in the concentration of DO. Strain at the maximum stress, e(SCC), was, however, independent of the concentration of DO, and depended on the number of cracks in the fracture surface. In case of applying potential, localized corrosion was found to generate beyond a critical potential of -370 mV(Ag/AgCl); cracks were observed from -370 to -340 mV(Ag/AgCl) and pit size increased with increase in applied potential. e(SCC) was found not to be sensitive to the applied potential, but to be mainly decided by the strain at which pit generated. The crack growth rate which was estimated by the analysis of the stress-strain curves was found to be almost constant in the potential range between -370 and -340 mV(Ag/AgCl).

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

Stress corrosion cracking (SCC) behavior of SUS316L stainless steel in the chloride solution containing thiosulfate has been investigated by using a slow strain rate technique (SSRT). The susceptibility of SCC was found to depend on the strain rate, the concentration of thiosulfate and chloride, and pH. The highest susceptibility was obtained at the condition of 20 mass%NaCl containing 10(-2) kmol.m-3 Na2S2O3 at pH 5.3 and 2.2 X 10(-7) s-1. Observations of fractured specimens showed that cracks perpendicular to the tensile axis generated at the pits. The initial fracture mode of the crack was intergranular, followed by transgranular and dimple with propagation of the crack. Intergranular fracture initiated from intergranular corrosion on the bottom of the pit, in which pH decreased less than 2. Immediately after immersion, pits generated easily because the dissolved oxygen with thiosulfate rapidly raise free corrosion potential upto pitting potential in cooperation with the action of thiosulfate to lower the pitting potential. Decrease in pH caused lowering of pitting potential and increase of the number of cracks, while the highest SCC susceptibility was obtained at pH 5.3. At conditions showing the high SCC susceptibility, corrosion potential was always in the range between -400 and -370 mV (Ag/AgCl). Therefore, the SCC behavior in this system is strongly controlled by the electrochemical factors.

Web of Science

researchmap

DOI： 10.3323/jcorr1974.39.6_303

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

Localized corrosion behavior of welds of type 304 stainless steel was investigated by using a scanning vibrating electrode technique in H2SO4 aqueous solutions containing various concentrations of KSCN at 298 K. The distribution of corrosion current density was measured during an electrochemical potentiokinetic reactivation test in 0.5 mol/l H2SO4 solution containing 10-2 mol/l KSCN. The weld metal, heat affected zone, and base metal can be distinguished for differences in the current density at the transition potential from passive to active region. The distributions of current density were measured during immersion in 0.5 mol/l H2SO4 solutions containing various concentrations of KSCN. The weld metal shows anodic peak current density at 10-4 mol/l KSCN, whereas it shows a cathodic peak current density at 100 mol/l KSCN.

DOI： 10.3323/jcorr1974.39.6_303

Scopus

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

DOI： 10.3323/jcorr.67.2

researchmap

DOI： 10.11457/swsj.71.1_11

researchmap

researchmap

DOI： 10.2464/jilm.65.416

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

DOI： 10.3323/jcorr.63.309

researchmap

DOI： 10.3323/jcorr.63.76

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

DOI： 10.3323/jcorr1991.47.78

researchmap

DOI： 10.2320/materia.36.311

researchmap

researchmap

researchmap

researchmap

Language：Japanese  

CiNii Books

researchmap

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：Toyama, Japan  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：WEB  

researchmap

Venue：日本科学未来館(中止：開催とする  

researchmap

Venue：日本科学未来館(中止：開催とする  

researchmap

Venue：日本科学未来館(中止：開催とする  

researchmap

Venue：日本科学未来館(中止：開催とする  

researchmap

Venue：東京工業大学(中止：開催とする)  

researchmap

Venue：東京工業大学(中止：開催とする)  

researchmap

Venue：Nancy, France  

researchmap

Venue：Yokohama, Japan, PACIFICO YOKOHAMA  

researchmap

Venue：Yokohama, Japan, PACIFICO YOKOHAMA  

researchmap

Venue：Yokohama, Japan, PACIFICO YOKOHAMA  

researchmap

Venue：東京農工大学 小金井キャンパス  

researchmap

Venue：札幌市教育文化会館  

researchmap

Venue：札幌市教育文化会館  

researchmap

Venue：札幌市教育文化会館  

researchmap

Venue：札幌市教育文化会館  

researchmap

Venue：札幌市教育文化会館  

researchmap

Venue：関西大学  

researchmap

Venue：関西大学  

researchmap

Venue：Dresden, Germany  

researchmap

Venue：岡山大学津島キャンパス  

researchmap

Venue：岡山大学津島キャンパス  

researchmap

Venue：岡山大学津島キャンパス  

researchmap

Venue：Seville, Spain  

researchmap

Venue：Nantes, France  

researchmap

Venue：Hyogo, Japan  

researchmap

Venue：大宮ソニックシティ  

researchmap

Venue：大宮ソニックシティ  

researchmap

Venue：関西大学  

poster

researchmap

Venue：関西大学  

poster

researchmap

Venue：東京電機大学  

researchmap

Venue：東京電機大学  

researchmap

Venue：東京電機大学  

poster 優秀ポスター賞

researchmap

Venue：大阪大学  

poster

researchmap

Venue：大阪大学  

poster

researchmap

Venue：大阪大学  

poster ベストポスター賞

researchmap

Venue：芝浦工業大学  

researchmap

Venue：芝浦工業大学  

researchmap

Venue：富山  

researchmap

Venue：富山  

researchmap

Venue：富山  

researchmap

Venue：富山  

researchmap

Venue：富山  

若手講演優秀賞

researchmap

Venue：石川県地場産業振興センター  

researchmap

Venue：東北大学  

researchmap

Venue：東北大学  

researchmap

Venue：東北大学  

researchmap

Venue：東北大学  

researchmap

Venue：Kracow , POLAND  

researchmap

Venue：Bologna , ITALY  

researchmap

Venue：東京ガーデンパレス  

若手技術者優秀発表賞

researchmap

Venue：Helsingor , DENMARK  

researchmap

Venue：日本科学未来館  

researchmap

Venue：日本科学未来館  

researchmap

Venue：千葉工業大学  

researchmap

Venue：千葉工業大学  

researchmap

Venue：千葉工業大学  

poster

researchmap

Venue：千葉工業大学  

poster

researchmap

Venue：千葉工業大学  

researchmap

Venue：神戸大学  

poster

researchmap

Venue：神戸大学  

poster

researchmap

Venue：神戸大学  

poster ベストポスター賞

researchmap

Venue：沖縄県市町村自治会館  

researchmap

Venue：沖縄県市町村自治会館  

researchmap

Venue：沖縄県市町村自治会館  

researchmap

Venue：沖縄県市町村自治会館  

researchmap

Venue：沖縄県市町村自治会館  

researchmap

Venue：九州工業大学  

researchmap

Venue：北海道大学  

researchmap

Venue：北海道大学  

researchmap

Venue：北海道大学  

researchmap

Venue：Praque, Chzech  

researchmap

Venue：東京ガーデンパレス  

researchmap

Venue：Rhodes, Greece  

researchmap

Venue：かごしま県民交流センター  

researchmap

Venue：日本科学未来館  

researchmap

Venue：日本科学未来館  

researchmap

Venue：首都大学東京  

researchmap

Venue：首都大学東京  

researchmap

Venue：首都大学東京  

researchmap

Venue：首都大学東京  

researchmap

Venue：首都大学東京  

researchmap

researchmap

Venue：大阪府立大学  

researchmap

Venue：大阪府立大学  

poster,ベストポスター賞

researchmap

Venue：大阪府立大学  

poster

researchmap

Venue：大阪府立大学  

poster

researchmap

Venue：芝浦工業大学  

researchmap

researchmap

researchmap

Venue：東海大学  

researchmap

Venue：大阪国際会議場  

researchmap

Venue：大阪国際会議場  

researchmap

Venue：大阪国際会議場  

若手講演奨励賞

researchmap

Venue：大阪国際会議場  

researchmap

Venue：大阪国際会議場  

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

poster

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

poster

researchmap

Venue：Monpelie, France  

researchmap

researchmap

Venue：Kyoto, Japan  

researchmap

Venue：Kyoto, Japan  

researchmap

Venue：Graz, Austria  

researchmap

Venue：大阪大学  

researchmap

Venue：大阪大学  

poster

researchmap

Venue：大阪大学  

優秀ポスター発表賞

researchmap

Venue：大阪大学  

poster,優秀ポスター発表賞

researchmap

Venue：関西大学  

poster

researchmap

Venue：関西大学  

poster

researchmap

Venue：関西大学  

poster

researchmap

Venue：関西大学  

poster

researchmap

Venue：東京理科大  

researchmap

Venue：東京理科大  

researchmap

Venue：東京理科大  

researchmap

Venue：東京理科大  

researchmap

Venue：東京理科大  

優秀ポスター発表賞

researchmap

Venue：大阪府大  

researchmap

Venue：大阪府大  

researchmap

Venue：大阪府大  

researchmap

Venue：大阪府大  

researchmap

Venue：Kansai Univ.  

researchmap

Venue：甲南大学  

優秀講演賞

researchmap

Venue：日本大学  

researchmap

Venue：日本大学  

researchmap

Venue：福岡工大  

researchmap

Venue：福岡工大  

researchmap

Venue：九州大学  

researchmap

Venue：九州大学  

researchmap

Venue：九州大学  

researchmap

Venue：九州大学  

researchmap

Venue：信州大学  

researchmap

researchmap

Venue：東京大学  

poster

researchmap

Venue：東京大学  

researchmap

Venue：東京大学  

researchmap

Venue：東京大学  

poster

researchmap

Venue：関西大学  

優秀発表者賞

researchmap

Venue：関西大学  

口頭発表 優秀発表者賞

researchmap

Venue：関西大学  

poster ベストポスター賞

researchmap

Venue：関西大学  

ベストポスター賞

researchmap

Venue：関西大学  

researchmap

Venue：関西大学  

poster

researchmap

Venue：米子  

researchmap

Venue：米子  

researchmap

Venue：米子  

コンペティション 若手優秀講演賞

researchmap

Venue：米子  

コンペティション

researchmap

Venue：東京工業大学  

researchmap

Venue：東京工業大学  

researchmap

Venue：東京工業大学  

researchmap

Venue：横浜国立大学  

researchmap

Venue：名古屋大学  

researchmap

Venue：名古屋大学  

poster

researchmap

Venue：名古屋大学  

researchmap

Venue：名古屋大学  

researchmap

Venue：名古屋大学  

researchmap

Venue：名古屋大学  

researchmap

Venue：Lausanne, Switzerland  

researchmap

Venue：Tronheim, Norway  

researchmap

Venue：東京工業大学  

researchmap

Venue：広島大学  

poster

researchmap

Venue：関西大学  

poster

researchmap

Venue：関西大学  

poster

researchmap

Venue：東京工業大学  

poster

researchmap

Venue：東京工業大学  

poster

researchmap

Venue：東京工業大学  

poster

researchmap

Venue：兵庫県立大学  

poster ベストポスター賞

researchmap

Venue：兵庫県立大学  

poster ベストポスター賞

researchmap

Venue：関西大学  

researchmap

Venue：横浜国立大学  

researchmap

Venue：横浜国立大学  

researchmap

Venue：コラッセ福島  

researchmap

Venue：コラッセ福島  

researchmap

Venue：金沢大学  

researchmap

Venue：金沢大学  

researchmap

Venue：金沢大学  

researchmap

Venue：金沢大学  

researchmap

Venue：金沢大学  

researchmap

Venue：Estoril, Portgal  

researchmap

Venue：Hawaii, USA