Decomposition behavior of high-Tc superconductor YBa2Cu3Ox in water

Autor:	Jun Takada, Naoichi Yamamoto, Masao Kiyama, Y. Miura, Hitoshi Kitaguchi, Yoichi Tomii, Akiyoshi Osaka, Teruyoshi Unesaki, Yoshio Oka
Rok vydání:	1987
Předmět:	Materials science Mechanical Engineering Metals and Alloys Inner core Analytical chemistry Mineralogy Electron microprobe Microstructure Decomposition Industrial and Manufacturing Engineering Autoclave Phase (matter) visual_art Materials Chemistry visual_art.visual_art_medium Ceramic Surface layer
Zdroj:	Journal of the Japan Society of Powder and Powder Metallurgy. 34:651-658
ISSN:	1880-9014 0532-8799
DOI:	10.2497/jjspm.34.651
Popis:	High-Tc superconductor YBa2Cu3Ox(x ≈ 6.8) reacts upon water to decompose. In order to clarify the process of decomposition, the microstructure of the YBC ceramics was studied by means of X-ray diffraction and EPMA after the reaction with water under autoclave and ambient conditions. Under the treatment in the autoclave above 100°C, the YBC ceramics were fully decomposed and Y(OH)3 or YOOH, Ba2+ and CuO were found in the solution. Due to the EPMA study on the samples treated under ambient conditions, three regions were confirmed in the grains: a) the inner core region without any interaction with water, b) the intermediate region of low Ba content surrounding the core, and c) the surface layer containing Y and Cu in the molar ratio Y/Cu=1/3 and very little amount of Ba. On these basis, it is concluded that the decomposition of the YBC ceramics is due to the diffuse-out of Ba cations to water and that the decomposition is not accompanied by the formation of Y2BaCuO5 phase.
Databáze:	OpenAIRE
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