SUS 310S Research Articles

Direct deposition of multi-walled carbon nanotubes onto stainless steel and YEF foils using a simple electrophoretic deposition for electrochemical capacitor electrode

Metals including metal alloys have been widely used as current collector in energy storage devices. Many papers reported the direct deposition of carbon materials like multi-walled carbon nanotube (MWCNT) onto aluminum or copper or stainless steel foils. However, it is important to note that the study of YEF 50, an engineering iron alloy and high performance stainless steel SUS 310S as current collector is very limited. This manuscript discusses the usage of electrophoretic deposition technique using the MWCNT colloids in isopropyl alcohol electrolyte during the direct deposition. Other than CNT characterization using several analytical techniques, electrochemical analyses confirmed the excellent capacitive performance of MWCNT electrode with the evidence of small internal resistance. From cyclic voltammetry measurement at 1 mV s−1, a relatively high specific gravimetric capacitance of 124 F g−1 and 89 F g−1 for YEF 50 and SUS 310S, respectively were obtained. Other than the intrinsic properties of the CNTs, the excellent capacitance is attributed to the polyvinyl alcohol react as adhesive material between MWCNT and the surface of conductive substrate.

Thermo-Mechanical Training of Stainless Steels to Improve Damping Capacity

The effects of thermo-mechanical training on damping capacity of two types of stainless steels, Fe-18Cr-8Ni (SUS 304) and Fe-25Cr-20Ni (SUS 310S) stainless steels, are studied. The thermo-mechanical training with bending deformation is adopted, since vibration manner in internal friction measurement is bending mode. An anisotropic damping capacity as well as hardness of samples is studied. It is found that deformation induced ε-martensite is observed for trained SUS 304 sample, while deformation twins are formed in the trained SUS 310S sample. It is also found that internal friction of SUS 304 sample is larger than that of SUS 310S sample. Increase in number of training results in an increase in the internal friction and hardness. In addition, anisotropic damping capacity is observed in the samples subjected the thermo-mechanical training. To be concluded, the thermo-mechanical training is useful for enhancement of both damping capacity and strength of SUS 304 and SUS 310S stainless steels.

Highly efficient growth of vertically aligned carbon nanotubes on Fe–Ni based metal alloy foils for supercapacitors

Supercapacitors are highly promising energy devices with superior charge storage performance and a long lifecycle. Construction of the supercapacitor cell, especially electrode fabrication, is critical to ensure good performance in applications. This work demonstrates direct growth of vertically aligned carbon nanotubes (CNTs) on Fe–Ni based metal alloy foils, namely SUS 310S, Inconel 600 and YEF 50, and their use in symmetric vertically aligned CNT supercapacitor electrodes. Alumina and cobalt thin film catalysts were deposited onto the foils, and then CNT growth was performed using alcohol catalytic chemical vapour deposition. By this method, vertically aligned CNTs were successfully grown and used directly as a binder-free supercapacitor electrode to deliver excellent electrochemical performance. The device showed relatively good specific capacitance, a superior rate capability and excellent cycle stability, maintaining about 96% capacitance up to 1000 cycles.

Characterization of Welded Austenitic Stainless Steel Precipitation during Elevated Temperature

The precipitation characterization of SUS 310S weld metal was investigated by TG/DSC and metallography technique. SMAW was selected for this study and then cut with water jet avoiding thermal effect. Austenitic is the main microstructure of weld metal because of high Creqv./Nieqv. Precipitation launched higher both %mass change and heat consumed as well as the precipitation temperature was around 800 degree Celsius.

Direct growth of vertically aligned single‐walled carbon nanotubes on conducting substrate and its electrochemical performance in ionic liquids

AbstractWe report the fabrication of vertically aligned single‐walled carbon nanotube (VA‐SWCNT) electrodes for a symmetric electrochemical capacitor using a simple, low‐cost ethanol‐based SWCNT growth system. From the CNT direct growth technique, the electrode was easily prepared and consequently assembled with an electrochemically stable ionic liquid as electrolyte. VA‐SWCNTs were directly grown on conducting SUS 310S foils in which the binder material was not incorporated in the capacitor structure. The morphology of as‐grown CNTs was investigated using scanning and transmission electron microscopy. This capacitor demonstrated a gravimetric capacitance of up to 584 F g−1 (at 1 mV s−1 scan rate) and a high‐rate capability, with up to 1000 mV s−1 scan rate being obtained. From the cyclic voltammetric analysis, the capacitance was contributed not only from the ideal double‐layer capacitance, but also from faradaic/redox processes that might have occurred during charge–discharge. Other than the capacitance, the VA‐SWCNT capacitor electrochemical performance was also measured by using frequency response (electrochemical impedance) and charge–discharge analyses.

Direct Growth of Vertically-Aligned Single-Walled Carbon Nanotubes on Conducting Substrates using Ethanol for Electrochemical Capacitor

A massive growth of vertically-aligned single-walled carbon nanotubes (VA-SWCNTs) from aluminum oxide (Al-O)-supported Co catalyst and high purity ethanol was performed using alcohol catalytic chemical vapor deposition (ACCVD) technique. SWCNTs with 50-μm thickness were grown on the substrates via this technique. The Al metal layer of 20 nm thickness was thermally-oxidized for the production of Al-O, and 0.5 nm cobalt (Co) thin films was used as catalyst for the CVD process. The CNT growth was optimized using SiO2/Si substrates, and similar experimental condition was applied to the conducting substrates. The as-grown CNTs were characterized using Raman spectroscopy and electron microscopies for growth confirmation and for quality level investigation. Development of the catalyst nanoparticles and Al-O support layer was observed using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The electrodes were fabricated using directly-grown VA-SWCNTs on SUS 310S, and were successfully used as an electrochemical capacitor. Electrochemical analysis using KOH aqueous electrolyte was performed by cyclic voltammetric (CV) and galvanostatic chargedischarge measurements; a maximum 52 Fg-1 specific gravimetric capacitance was obtained from the VA-SWCNT electrodes.

低温における SUH660 鉄基合金及びオーステナイト系ステンレス鋼の内部可逆水素脆化に及ぼす温度の影響

The internal reversible hydrogen embrittlement (IRHE) of the thermally hydrogen-charged iron-based superalloy of SUH660 and austenitic stainless steels of SUS 304, 316, 316L, 316LN and 310S was investigated in the temperature range from 300K to 80 K. Hydrogen showed a marked effect on the tensile properties of SUH660 and SUS 304, a minimal effect on those of SUS316 and SUS316LN, and no effect on those of SUS 310S and 316L at room temperature. Although the IRHE of SUH660 decreased with decreasing temperature, those of SUS304, 316 and 316LN increased with decreasing temperature, reached a maximum at around 200 K, and decreased rapidly with decreasing temperature down to 80 K. It was observed that hydrogen caused transgranular fracture along the slip plane in the iron-based superalloy and brittle transgranular fracture along the strain-induced martensite lath in the austenitic stainless steels, respectively. It was suggested that IRHE of the SUH660 depended on the diffusion of hydrogen, and that IRHE of the austenitic stainless steels from 300 K to the maximum IRHE temperature depended on the transformation of strain-induced martensite and the behavior below the maximum IRHE temperature depended on the diffusion of hydrogen.

Corrosion of Stainless Steel Bipolar Plates in PEFC

Stainless steels are one of the most promising materials as bipolar plates for polymer electrolyte membrane fuel cells (PEFCs). In use of stainless steel bipolar plates, however, corrosion and corrosion induced degradation of cell performance are anticipated. In the present study, corrosion behavior of SUS 304 and 310S stainless steels was investigated through polarization tests in the simulated PEFC environment (0.05M Na2SO4 (pH 2.3) + 2 ppm F solution at 353 K), contact resistance measurement between steels and carbon diffusion layer and cell operation. XPS analysis was also carried out to compare the steel surfaces after polarization measurements and cell operation. The results indicated that passive current density for SUS 310S stainless steel in the simulated PEFC environments was lower than that for SUS 304 stainless steel, as expected from higher Cr content. Longer polarization of these steels decreased the passive current density but increased contact resistance due to thickening of the passive film. The cell voltage drops after 3.6 x 10^6 s operation were 14 mV for graphite, 22 mV for SUS 310S and 46 mV for SUS 304 steel. Apparent corrosion was recognized for SUS 304 stainless steel served for cathode.

高温ＮａＯＨ‐Ｎａ２Ｓ水溶液中のステンレス鋼の応力腐食割れ挙動と最適材料

The selection of stainless steels to prevent stress corrosion cracking (SCC) in hot sodium hydroxide solution containing small amount of sodium sulfide was determined by order of the critical temperature of SCC occurrence and by the electrochemical behaviour. SCC susceptibility of stainless steels might be governed by chemical compositions, the nickel and chromium content.It was possible to presume that SUS 310S had enough resistance to use in industry.In comparison with SCC behaviour of SUS304L conducted with various SCC test methods, the detecting SCC was able to reproduce with not only the Lehigh restraint test but also the slow strain rate tensile tests at the same test conditions as in the U-bend test.

ＳＵＳ３１０Ｓステンレス鋼の機械的性質に及ぼすアルミニウム拡散被覆の影響

A new method has been developed to diffuse aluminum onto austenite stainless steel sheet. In the present study, samples diffused Al onto SUS 310S stainless steel were made by changing the thickness of Al foil attached on the surface of SUS 310S and varying heat treatment conditions. The structural changes in the diffusion layer and the mechanical properties of the samples were then investigated. The diffusion layer consisted of two layers: Layer I was α2 (FeAl) and layer II was a mixed structure of NiAl and α. Kirkendall voids were observed between the two layers. The hardness of layer I increased with increasing Al concentration, which was consistent with that of Fe-Al intermetallic compounds reported by others. That of layer II and the substrate was hardly changed by the aluminized coating. Tensile properties were strongly affected by surface cracks occurring on the diffusion layer during loading. The number of serrations appeared after yielding on the stress-strain curve correlated to that of cracks. The yield strength of layer I was evaluated by rule of mixtures, in which the yield strength had a peak in the vicinity of an Al concentration of 20wt% because of the strengthening mechanism brought about by mixing ordered and disordered phases. The tensile strength and elongation of samples decreased with increasing the thickness of the diffused layer and decreasing Al concentration due to the effect of three-axis stress under the crack tip.

ＳＵＳ ３１０Ｓステンレス鋼に処理したアルミニウム拡散被覆層の破壊挙動

Cracks occurred on the Al-diffused surface of specimens of type SUS 310S stainless steel during tension loading was observed by a plastic replica technique. The initiation of cracks depended on the Al concentration in the diffusion layer; the strain at which cracks initiated decreased and the number of cracks increased with increasing Al concentration. Cracks occurring at low strain grew with increasing crack opening displacement and a small increase in the number of cracks during tension loading. The fracture strength of the diffusion layer at strain in which cracks just initiated was estimated by the rule of mixtures, considered that the diffused material consisted of two layers of the diffusion layer and the substrate. The fracture strength increased with the increasing degree of order of the α2 phase in the diffusion layer. Energy accumulated in the diffusion layer during tension loading was calculated from a strain-stress curve as energy was released by crack formation. Energy decreased with the increasing degree of order of the diffusion layer. This phenomenon corresponded to the fracture behavior of the layer, that is, change in fracture surfaces from cleavage to intergranular fracture.

Corrosivity of Molten Alkali and Alkaline Earth Carbonate to SUS 310S under a Simulated MCFC Cathode Environment

Corrosivity of Molten Alkali and Alkaline Earth Carbonate to SUS 310S under a Simulated MCFC Cathode Environment

ＳＳＲＴ法によるＳＵＳ３１０Ｓ鋼単結晶の応力腐食割れ

The stress corrosion cracking (SCC) of SUS 310S steel single crystals was investigated by the slow strain rate technique. The smoothed specimens oriented for [001], [101] and [111] were prepared, and each susceptibility to SCC was evaluated from the nominal stress-strain curves in a boiling 42% MgCl2 solution at 416K. The results indicated that the transgranular cracks occurred at the strain rate below 2.38×10-5S-1, and the tensile strength and elongation decreased with decreasing strain rate. The fracture surface of which the appearance was changed by the tensile axis orientation, was formed by the crack growth along ‹110› direction on {100} plane. The susceptibility index to SCC defined by comparing with the nominal stress-strain curves in noncorrosive oil decreased with decreasing strain rate, whereas it was independent of tensile axis orientation. With a longer time to fracture (a lower strain rate), the normal stress to the (001) crack plane nearly became coincident with that on the threshold of SCC obtained by the constant load technique. This fact demonstrates that the susceptibility to crack growth is strongly controlled by the normal stress to the crack plane.

ChemInform Abstract: Corrosion Behavior of Ni and Ni‐Based Alloys in Concentrated NaOH Solutions at High Temperatures.

AbstractThe corrosion behavior of SUS 310S austenitic stainless steel, Alloy 600, Monel 400, and Ni 200 in 30‐60% NaOH is studied at temp. up to 166 °C. In solutions containing dissolved oxygen or under oxidizing conditions, all alloys studied are corroded seriously due to oxygen diffusion through the porous oxide layer consisting of β‐Ni(OH)2, whereas in hydrogen‐saturated solutions the samples are corrosion resistant.

Corrosion Behavior of Ni and Ni‐Based Alloys in Concentrated NaOH Solutions at High Temperatures

Corrosion behavior of SUS 310S austenitic stainless steel, Alloy 600, Monel 400, and Ni 200 in solutions in the concentration range 30–60% at high temperatures up to 166°C was studied. In solutions containing dissolved oxygen or under oxidizing conditions, all the specimens examined were corroded seriously due to oxygen diffusion through the porous oxide layer consisting of . In hydrogen‐saturated solutions, on the other hand, these Ni alloys were corrosion resistant because nickel in the alloys was active to oxidation of hydrogen. The specimens were corroded by deaerated solution at high temperatures in which hydrogen evolution took place as the counterreaction. The corrosion rate controlled by the hydrogen formation reaction increased exponentially with the decrease of the Ni content in the alloy.

ＳＵＳ３１０Ｓ鋼単結晶の応力腐食割れとその結晶学的研究

The effect of tensile axis on stress corrosion cracking (SCC) of SUS 310S steel single crystals in a boiling MgCl2 solution (42%) at 416K was studied under the constant-loading conditions.The threshold stress for SCC decreased in order of tensile axes of [111], [101] and [001], and was independent of Schmid factors for the primary slip system. Cracks were preferentially nucleated from the micro-pits at slip steps by plastic deformation and grew along the ‹110› direction on the {100} plane in every type of specimens. The fracture surface of [001]-oriented specimen was observed to be flat, but those of the rest contained steps composed of other {100} planes, too. It was found that the normal stress to the {100} crack plane vs. fracture time curves in all types of specimens coincided well. This fact suggests that the crack growth is strongly controlled by the normal stress to the {100} plane which makes the smallest angle with respect to the tensile axis.

極低温におけるオーステナイト系ステンレス鋼の時間依存変形

Creep tests and constant load rate tensile tests at cryogenic temperatures were made on austenitic stainless steels, SUS 304L, 310S and 316L. Creep rate of about 10-9s-1 was observed in 200 hour creep test under the proof stress of the materials at 77K, and creep rate at 4K was decreased to a tenth at 77K.On the other hand, an abrupt and large deformation occurs in a constant load rate tensile test at 4K. The magnitude of the abrupt deformation depends on the workhardening rate and the stability of austenitic phase. Higher proof stress materials, especially SUS 310S, do not always show better characteristics for the creep or the abrupt deformation at 4K.

液体ヘリウム中での金属材料の引張挙動におよぼす歪み速度の影響

Tensile test was carried out on four alloys at liqud helium temperature to study the effect of strain rate on the deformation behavior. Alloys used were Fe-13%Ni alloys, SUS 304L, SUS 310S and 5083-O aluminum alloys, which were fully ductile even at liquid helium temperature.At lower strain rate serrated flow was observed for every alloy, and at higher rate all flow curves became smooth. Proof stress has little strain rate dependence, but tensile stress decreases with an increase in strain rate. The latter fact would be associated with adiabatic deformation, which depends upon the thermal properties of the alloys at low temperatures.

ＳＵＳ３１０Ｓ鋼粗大結晶のＭｇＣｌ２溶液中における応力腐食割れ破面解析

The stress corrosion cracking (SCC) of SUS 310S stainless steel having coarse grain structure in boiling MgCl2 solutions was studied fractographically by a scanning electron microscope. The crystallographic orientation of transgranular fracture mode in SCC was determined with the aid of etch-pitting technique.The mode of crack propagation during SCC-tests depended on the orientation of coarse grain, and the crack growth showed a delay of several ten minutes at grain boundaries, twin boundaries or crack branching points. On the other hand, the mode of transgranular fracture was characterized by a fan-shaped pattern, which was formed mostly by the crack growth along <110> direction on {100} plane. On this fracture surface, a striation-like pattern was found locally as the result of slip lines formed perpendicular to the direction of crack growth.The above results imply that the transgranular fracture in SCC occurs crystallographically by the interaction of sessile dislocation with corrosive environment.

溶接施工管理へのＡＥ法の適用に関する研究 ＩＩ ＡＥ法による高温割れの検出

AE of hot cracking has been monitored and quantitatively correlated with crack length for SUS 310S stainless steel on TIG welding. It was found that there exists a linear relationship between length of hot cracking and the total summation of AE counts, and the total summation of AE energy also.AE signal from weld specimen can be classified three types of AE signal from theirs shape and frequency spectra by using the AE monitoring system.The frequency spectra of their AE signals were distinguished, especially, the different distribution of frequency band from DC to 400 kHz. It is considered that the source of A type AE signal was generated at hot cracking, the type B one was generated from sound of friction between weld specimen and jig, and the type C was generated from arc noise only during welding.These classification of AE signals could be useful for the practical application of acoustic emission monitoring to welding situations.