A5083449385- Hydrogen embrittlement and corrosion behaviors in metals
- Corrosion Behavior and Inhibition
- Electrodeposition and Electroless Coatings
- Anodic Oxide Films and Nanostructures
- Nuclear Materials and Properties
- Electrocatalysts for Energy Conversion
- Concrete Corrosion and Durability
- Microstructure and Mechanical Properties of Steels
- Non-Destructive Testing Techniques
- Molecular Junctions and Nanostructures
- Electrochemical Analysis and Applications
- Metal and Thin Film Mechanics
- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Gas Sensing Nanomaterials and Sensors
- Surface Treatment and Residual Stress
- Material Properties and Failure Mechanisms
- Copper-based nanomaterials and applications
- Aluminum Alloy Microstructure Properties
- Nanomaterials for catalytic reactions
- Solidification and crystal growth phenomena
- Metallurgy and Material Forming
- Gold and Silver Nanoparticles Synthesis and Applications
- Supercapacitor Materials and Fabrication
- Acoustic Wave Resonator Technologies
Kobe Steel (Japan)
2015-2023
Kyoto University
2009-2015
Materials Science & Engineering
2011
Abstract An aging treatment of UNS S32750 super duplex stainless steel at 1173 K for 1.0 ks produced σ and secondary austenite (γ 2 ) phases in the α γ phase boundary regions. Small amount Mn-Cr oxide MnS complex inclusions were present steel. No pitting was observed during potentiodynamic polarization a small area (200 × 200 µm) without 1 M MgCl 348 K. Because electrode included α, γ, σ, phases, these their boundaries alone could not act as initiation sites pitting. The size gradually...
Metal nanowire nonwoven cloth (MNNC) is a metal sheet that has resulted from intertwined nanowires 100 nm in diameter with several dozen micrometers of length. Thus, it new metallic material having both flexibility the and large specific surface area nanowires. As an application utilizes these properties, we propose high-cyclability electrode for Li storage batteries, which active deposited or coated on MNNC. The proposed can work without any binders, conductive additives, current...
Nickel nanowires were synthesized via electroless deposition in an organic solvent (ethylene glycol) under a magnetic field. Deposition behavior of nickel particles and wires electrochemically investigated at various concentrations NaOH by in-situ mixed potential measurement voltammetry combined with quartz crystal microbalance. Based on the electrochemical investigation, formation mechanism is proposed. According to mechanism, 100–370 nm diameter several dozen μm length successfully...
Co-Ni nanowires 40–100 nm in diameter with several dozen μm of length were prepared via electroless deposition under a magnetic field. The formation was investigated by an in-situ mixed potential measurement and cyclic voltammetry combined quartz crystal microbalance electrode. These electrochemical measurements revealed that the rate nickel on is lower than cobalt cobalt. Nickel works as inhibitor growth process alloys. Thus, thickness alloy drastically reduced addition Ni(II) solution....
By using phase-field computer simulations, we have investigated the effects of coherent strain due to phase separation in olivine-type LiFePO4. In this system, elastic-strain energy lattice mismatch between LiFePO4 and FePO4 phases accompanied by insertion extraction Li ions is considered play a crucial role kinetics during charge/discharge process. The present micromechanics simulations reveal several significant features LiFePO4/FePO4 system accompanying strain, such as retardation...
The synthesis process of Co–Ni alloy nanoparticles via electroless deposition in ethylene glycol (EG) was electrochemically investigated. Insufficient thermodynamic data for organic solvents prevented us from calculating the oxidation–reduction (redox) potentials Co(II)/Co and Ni(II)/Ni redox pairs solvents. In present work, however, EG were determined by using voltammetry combined with quartz crystal microbalance. cyclic voltammograms, current cobalt on substrate much higher than that...
The effect of shot peening and subsequent low-temperature annealing (SP treatment) on hydrogen embrittlement in tempered martensitic steel was investigated comparing the typical charging methods, constant current controlled cathodic test combined cyclic corrosion (CCT). entry behavior evaluated by permeation technique visualization using secondary ion mass spectrometry. SP treatment improved resistance both methods. On other hand, different depending method. suppressed because compressive...
The synthesis process of cobalt nanoparticles via electroless deposition in ethylene glycol (EG) was investigated by electrochemical quartz crystal microbalance (QCM). oxidation–reduction potential the Co(II)/Co redox pair EG could not be thermodynamically calculated because insufficient thermodynamic data organic solvents. We experimentally determined cyclic voltammetry combined with QCM. reaction start and end points were also effect nucleating agent on behavior particle size distribution examined.
The formation of Fe-Co nanoparticles and nanowires via electroless deposition under a magnetic field was electrochemically investigated by an in-situ mixed potential measurements, quartz crystal microbalance measurement, cyclic voltammetry. These electrochemical measurements revealed that the in metallic salt solution is due to disproportionation reaction Fe(II). Addition hydrazine results nucleation growth particles. rate becomes lower at higher concentration Fe(II) owing catalytic activity...
The effect of Ta addition on the pitting corrosion resistance duplex stainless steels was investigated in both cases without and with deoxidization/desulfurization by Al Ca. improved two proposed mechanisms. For Ca, MnS inclusions which act as initiation sites are modified to electrochemically-stable (Ta,Mn) oxysulfides. (CaS (Al,Ca)oxides) coated stable Ta-containing nitrides resulting suppression propagation.
耐孔食性に優れる二相ステンレス鋼の開発には，孔食の起点となる介在物の制御が重要である．本研究では，元素添加による介在物改質に着目し，代表的な孔食起点であるMnSを例に，耐孔食性向上技術の探索を行った．その結果，Taを添加した二相ステンレス鋼は優れた耐孔食性を示すことが見出された．Ta添加による耐孔食性向上メカニズムは，孔食起点となるMnSが電気化学的に安定なTa‐Mn‐S‐Oに改質されたことに起因すると推察された．
In order to clarify the mechanism of hydrogen embrittlement in high strength steel, it is necessary evaluate local concentration stress and strain fields where considered occur. There are several ways visualize hydrogen, but SIMS advantageous that can detect directly without reaction. this study, visualization accumulated field was tried using SIMS. Hydrogen flux intensity bent portion U-bend specimen, gradient exists, changed according gradient, higher on outside bending than inside, with...
耐局部腐食性に優れる二相ステンレス鋼の開発には，局部腐食の起点となる介在物の制御が重要である．本研究では，Ta添加による介在物改質がスーパー二相ステンレス鋼のすきま腐食に及ぼす影響について調査した．その結果，Ta添加により耐すきま腐食性は向上することが明らかになった．Taを含有しないベース鋼に見られたMnSはすきま腐食試験後に溶出しており，これがすきま腐食の起点になっていることが示唆された．一方，Ta添加鋼では，すきま腐食起点となるMnSの一部がTaを含む酸硫化物（Ta‐Mn‐S‐O）に改質されており，これはMnSの溶解が見られた試験溶液への浸漬後でも変化が見られないことから，電気化学的に安定であることが明らかになった．Ta添加による耐すきま腐食性向上メカニズムは，MnSの一部がTaを含む酸硫化物に改質され，すきま腐食の起点が減少したことに起因すると推察された．
Vanadium carbide (VC) in high strength steels is divided into two types, i.e., finely formed precipitated VC and coarsely undissolved VC. The behavior of hydrogen trapped at the types has been investigated using thermal desorption analysis (TDA). Specimens containing different amounts V (0, 0.10 0.15 %) were prepared. with 0 % (QT) quenched 900 ☐ tempered 600 ☐. Some specimens are denoted here as (Q). Hydrogen was charged by immersion a NH4SCN aqueous solution analyzed TDA. end temperatures...
二相ステンレス鋼は高耐食性・高強度を有するが，塩化物イオン濃度の高い環境中では介在物（MnS）を起点として孔食が発生する．本報では実製品レベルのS量を有するスタンダード二相ステンレス鋼を用いて，Ta添加量が腐食挙動に及ぼす影響について検討した結果，0.06 mass％以上Taを添加すると耐孔食性が向上することを見出した．
The formation of nickel nanowires by electroless deposition was electrochemically investigated an in-situ quartz crystal microbalance measurement combined with mixed potential measurement. These electrochemical measurements revealed that the control a terminal point reaction is critical for nanowires. has been controlled adjusting concentration sodium hydroxide and trisodium citrate. Based on mechanism nanowires, 100-370 nm in diameter several dozen μm length were successfully prepared...
The formation process of Co, Ni, Co-Ni alloy nanoparticles by electroless deposition in nonaqueous solution (ethylene glycol: EG) was electrochemically investigated. When the solvent decomposes during cathodic reduction relatively-less noble metals (Co, Fe, etc.) , current is hardly measured from total voltammetry because large contribution decomposition solvent. In this work, Co and Ni evaluated a weight change due to metal on quartz crystal microbalance electrode. substrate much higher...
自動車用鋼板の高強度化に伴い水素脆化が懸念される.本研究では,1500 MPa級の高張力鋼板をU曲げ形状で大気腐食環境下に暴露し,水素脆化特性を評価した.曲げ部の半径が5 mm,10 mm,15 mm,負荷応力が1300 MPa,1500 MPaの条件において,銚子36ヶ月,宮古島海岸12ヶ月で水素脆化による割れは生じなかった.一方,宮古島海岸20ヶ月で割れが確認された.宮古島海岸24ヶ月で板を貫通する腐食が生じたことから,割れは腐食減肉により生じたと考えられる.
Abstract not Available.
High strength steel sheets are increasingly being used due to the growing need improve fuel efficiency by reducing vehicle weight. Steel usually as automotive parts formed pressing, etc., and complicated strain is generated in sheet after forming. This thought affect occurrence of hydrogen embrittlement. In this study, a new embrittlement evaluation method using forming limit diagram was devised. A with level adjusted 1470 MPa prepared for uniaxial, plane biaxial modes, stress were applied...
The effect of blasting on hydrogen analysis was investigated with the aim establishing a method for precisely measuring that entered steel in corrosive environment. existing states specimens blasted under various conditions were analyzed using thermal desorption and visualization by secondary ion mass spectrometry. phenomenon entry into demonstrated first time. It should be noted is remarkable case specimen large specific surface area, becomes an inhibitory agent measurement content steel....