Preparation and grain boundary chemistry of dense polycrystalline YBa2Cu4O∼8

Autor:	J. O. Scarbrough, G. C. Marsh, J. Brynestad, D. M. Kroeger, Robert K. Williams, R. A. Padgett, T. J. Henson
Rok vydání:	1991
Předmět:	Auger electron spectroscopy chemistry.chemical_compound Chemistry Hot isostatic pressing Electrical resistivity and conductivity Oxide Analytical chemistry General Physics and Astronomy Mineralogy Grain boundary Crystallite Microstructure Hot pressing
Zdroj:	Journal of Applied Physics. 69:2426-2430
ISSN:	1089-7550 0021-8979
Popis:	Dense polycrystalline samples of the compound YBa2Cu4O∼8, Y124, were prepared by a three‐step procedure. In the first step a mixture of Y2O3, CuO and BaO2 was reacted at 960 °C under an oxygen pressure of 55 bar. The compound did not sinter under these conditions but electrical resistivity and susceptibility measurements showed that the oxide mixture converted to Y124. In the second step densification was produced by hot isostatic pressing at 875 °C. This degraded the superconducting properties severely and a final high‐temperature anneal in pressurized oxygen was required to restore optimum properties. This anneal consisted of a one hour hold at 1010 °C in 40‐bar O2 followed by a 24‐h anneal at 950 °C in 55‐bar O2. After this treatment the samples were ∼90% dense, phase pure Y124. The maximum grain dimensions were about 10 μm, and Auger spectroscopy data were obtained on a fracture surface. These data showed that the grain boundary composition does not differ significantly from the bulk values.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b95a71902a42400410b0536f7365a5d6 https://doi.org/10.1063/1.348677 Zobrazit plný text záznamu