A5059795699- Hydrogen embrittlement and corrosion behaviors in metals
- Corrosion Behavior and Inhibition
- Microstructure and Mechanical Properties of Steels
- Nuclear Materials and Properties
- Metal Alloys Wear and Properties
- Concrete Corrosion and Durability
- Non-Destructive Testing Techniques
- Fatigue and fracture mechanics
- Material Properties and Failure Mechanisms
- High-Temperature Coating Behaviors
- Metallurgy and Material Forming
- Welding Techniques and Residual Stresses
- Analytical Chemistry and Sensors
- Magnetic Properties and Applications
- Advanced Chemical Physics Studies
- Optical Coatings and Gratings
- High Temperature Alloys and Creep
- Advanced Materials Characterization Techniques
- Photonic Crystals and Applications
- Electrochemical Analysis and Applications
- nanoparticles nucleation surface interactions
- Gas Sensing Nanomaterials and Sensors
- Anodic Oxide Films and Nanostructures
- Thermography and Photoacoustic Techniques
- Experimental and Theoretical Physics Studies
Tohoku University
2020-2025
Institute for Materials Research, Tohoku University
2021-2023
Tokyo Institute of Technology
2019-2021
Materials Science & Engineering
2019
The microscopic hydrogen diffusion in UNS S32750 super duplex stainless steel was analyzed using a polyaniline-nickel-based video imaging system. flux the body-centered-cubic ferrite (α) phases larger than face-centered-cubic austenite (γ) phases, causing from α to γ phases. order of as follows: (high) center > near α-γ boundaries (low). grain size also affected distribution. A small phase led large around phase, because effect outflux increased with decreasing distance boundary.
Hydrogen, the key element for solving major environmental issues, exhibits rapid diffusion and localization in lattice defects of metals, which leads to embrittlement. However, microstructure-hydrogen interactions metallic materials are poorly understood. Therefore, a technique capturing microstructure-dependent hydrogen real-time has long been targeted by researchers. Here, we successfully visualized preferential at grain boundaries (GBs) pure Ni using video imaging system. A thin...
Local hydrogen entry under a NaCl droplet on Fe sheets was analysed by employing hydrogenochromic sensor and electrochemical permeation tests. Large crystallographic pits barely promoted entry, because pitting proceeded at potentials higher than the potential of evolution reaction. Hydrogen accelerated acidification an island-like rust layer. The layer became thick in its outer regions, mainly owing to severe corrosion alkalisation around rust-formed area. prominent after disappearance...
In this study, we investigated the hydrogen absorption behavior of pre-rusted steel in an NaCl droplet by measuring permeation current and corrosion potential. To prepare steel, a 30-μL 0.1-mol/dm3 solution was placed on surface exposed to wet-dry cyclic conditions changing relative humidity (RH) repeatedly from 40% 95% at constant rate 27.5%/h 298 K. The potential were measured during drying electrolyte using electrochemical test Kelvin probe (KP) technique, respectively. shifted negative...
To investigate hydrogen absorption behavior into carbon steel during corrosion in an aqueous sodium chloride (NaCl) droplet, a simultaneous measurement system of the potential, Ecorr and permeation current, iper was developed using Kelvin probe (KP) technique Devanathan–Stachurski (DS) method, respectively. This outputs interrelation between throughout drying process NaCl droplet. Our results showed that occurred when shifted less noble direction under wet conditions, ceased at higher...
Abstract Hydrogen is one of the key elements for economy based on renewable and sustainable resources. Because a very low concentration hydrogen in metallic structural materials often causes embrittlement decreases their mechanical property, there great interest development an inexpensive versatile sensor metals with high sensitivity spatial resolution. Here, real‐time visualization atomic state metal has been successfully achieved using hydrogenochromic consisting conventionally fabricated...
In this study, pH measurement was performed in a thin electrolyte droplet with thickness <1000 µm by the of equilibrium electrode potential an Sb/SbxOy used as sensor. The evaluated using Kelvin probe (KP) technique. To investigate response Sb droplet, dependency Volta difference between and gold wire KP on measured. had linear respect to buffer solution pH, independent thickness. This result indicates that technique, combined electrode, is sensitive ≥50 µm. technique also applied measure...
The effects of residual stress on the hydrogen embrittlement behavior a tempered martensitic steel sheet with 1-GPa-class tensile strength stretch-formed by hemisphere punch simulating press-formed automotive structural parts were investigated. Cracking specimen induced potentiostatic charging was initiated in foot impression and propagated to radial direction both toward hillside plain. mixture quasi cleavage intergranular fractures observed whole through fracture surface. Residual...
To evaluate the susceptibility of steels to hydrogen embrittlement, it must be charged and have its content controlled before any mechanical testing. In this study, permeation tests an iron sheet were performed during potentiostatic charging in various solutions containing ammonium thiocyanate obtain a guideline for efficient wide range contents. As polarization potential shifted negative direction, current increased becoming almost constant. all cases, besides when aqueous sodium hydroxide...
The effect of iron rust on hydrogen uptake into steel during corrosion under an aqueous NaCl droplet was investigated. Pre-rusted obtained by exposing a coupon to natural environmental conditions for 1 month at the Choshi site Japan Weathering Test Center. that formed partly removed, and model rust/steel samples differing in area ratios rusted bare were prepared. permeation current potential simultaneously measured Devanathan-Stachurski (DS) method Kelvin probe technique, respectively. As...