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Your search keyword '"Nishimoto, Masashi"' showing total 132 results
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132 results on '"Nishimoto, Masashi"'

19. Uterine rupture in intramural ectopic pregnancy: A case report

Author

Washio, Keiichi, primary, Komatsu, Masato, additional, Tomimoto, Masako, additional, Uchida, Akiko, additional, Sasagawa, Yuki, additional, Nishimoto, Masashi, additional, Nagamata, Satoshi, additional, Yamasaki, Yui, additional, Tanimura, Kenji, additional, and Terai, Yoshito, additional

Published
2023
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35. Effect of quenching in aqueous polyvinylpyrrolidone solutions on the microstructure and pitting corrosion resistance of AISI 1045 carbon steel.

Author

Nishimoto, Masashi, Muto, Izumi, Doi, Takashi, Kawano, Kaori, and Sugawara, Yu

Subjects
*PITTING corrosion, *CARBON steel, *CORROSION resistance, *CARBON steel corrosion, *MICROSTRUCTURE, *AQUEOUS solutions, *FERRITES, *POVIDONE
Abstract

Carbon steels are widely used as infrastructure components owing to their high strength, ductility, and weldability. However, as corrosion degrades critical infrastructure components, exploring the relationship between the microstructure and corrosion resistance of carbon steel is of particular interest in engineering. To analyze this relationship, it is first essential to evaluate the corrosion resistance of each microstructure in a carbon steel specimen with a single chemical composition to eliminate the effects of alloying elements. In this study, we compared the pitting corrosion resistance of four microstructures (water‐quenched martensite, tempered martensite, bainite and degenerate pearlite, and ferrite–pearlite) of an AISI 1045 medium‐carbon steel. The pitting corrosion resistances of the microstructures in near‐neutral pH solutions containing NaCl were ordered as follows: (high) water‐quenched martensite > bainite and degenerate pearlite > tempered martensite > ferrite–pearlite (low). Elucidating the effect of the microstructure on the pitting corrosion resistance may contribute to the development of corrosion‐resistant carbon steels with excellent mechanical properties. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Fabrication of a model specimen for understanding micro-galvanic corrosion at the boundary of α-Mg and β-Mg17Al12.

Author

Shao, Zheng, Nishimoto, Masashi, Muto, Izumi, and Sugawara, Yu

Subjects
ELECTROLYTIC corrosion, OPEN-circuit voltage, CATHODES, SURFACE analysis, CORROSION resistance, ANODES
Abstract

A model specimen with a single boundary of the α/β phase simulating Mg-Al alloys was successfully fabricated by spark plasma sintering. A small electrode area of α phase or β phase was prepared using the model specimen, and the OCPs (open-circuit potentials) of each phase and a small electrode area containing the α/β phase boundary in 0.1 M NaCl at pH 8.0 were compared: the β phase exhibited a higher potential, and the α phase showed a lower potential. The OCP of the small area containing the α/β phase boundary was the intermediate value of these phases. In a small area containing α/β phase boundary, discoloration and gas bubbles were observed on the α phase, but no bubble generation was detected on the β phase. The gas bubbles were initially generated on the α phase near the β phase, but as the discoloration (corrosion) of the α phase approached the β phase, the bubbles were generated on the β phase. In micro-galvanic corrosion of the α and β phases, the β phase did not always function as the preferred cathode. The α phase partially corroded (or discolored) and became the anodes, so that the surrounding areas were most likely to be the cathodes. When corroded areas (anodes) in the α phase approached the β phase, the β phase would become cathodes. In addition to the micro-galvanic corrosion mechanism, the role of Al in corrosion resistance at the α/β phase boundary was determined by surface analysis. [ABSTRACT FROM AUTHOR]

Published
2023
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