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Effect of Oxygen Loss on Densification When Hot Isostatic Pressing YBa 2 Cu 3 O 7−δ
Author(s) -
Niska John,
Loberg Bengt,
Easterling Kenneth
Publication year - 1989
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1989.tb07691.x
Subject(s) - hot isostatic pressing , tetragonal crystal system , orthorhombic crystal system , materials science , oxygen , superconductivity , hot pressing , phase (matter) , pressing , mineralogy , metallurgy , composite material , microstructure , crystallography , crystal structure , condensed matter physics , chemistry , physics , organic chemistry
Hot isostatic pressing of the high‐T c superconductor YBa 2 Cu 3 O 7−δ can lead to loss of oxygen and transformation of the material from the high‐T c orthorhombic phase to the nonsuperconducting tetragonal phase. It is shown that glass encapsulation helps retain the orthorhombic structure, whereas steel encapsulation resulted in formation of the tetragonal phase. Reasons for this phenomenon are discussed. The equilibrium oxygen gas pressure for the oxygen decomposition reaction in YBa 2 Cu 3 O 7 , however, prevents full densification of this material in glass when employing hot isostatic pressing conditions of 200 MPa and 845°C.