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Solid‐State Sintering of YBa 2 Cu 3 O x in Different Oxygen Partial Pressures
Author(s) -
Poisl W. Howard,
Chaklader Asoke C. D.
Publication year - 1993
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.1151-2916.1993.tb03737.x
Subject(s) - sintering , activation energy , partial pressure , oxygen , isothermal process , materials science , ceramic , analytical chemistry (journal) , atmospheric temperature range , oxygen pressure , compaction , diffusion , mineralogy , metallurgy , chemistry , thermodynamics , composite material , physics , organic chemistry , chromatography
The effect of oxygen partial pressure, ranging from 0.001 to 1.0 atm, and temperature, in the range of 930°–955°C, on the solid‐state sintering kinetics of the superconducting ceramic YBa 2 Cu 3 O 7‐δ has been studied. Isothermal compaction rates between 930° and 955°C reached a maximum at some critical PO 2 (PO 2 CRIT ), with decreasing rates both above and below this oxygen partial pressure. This behavior was not observed for YBa 2 Cu 3 O 7‐δ sintered at 960°C, when a liquid phase is present. The activation energy for sintering above PO 2 CRIT has been estimated to be ∼190 kJ/mol, whereas below PO 2 CRIT it was found to be ∼130 kJ/mol. The oxygen ion diffusion was considered to be the rate‐determining step above PO 2 CRIT , while it is hypothesized that lattice strain caused by the formation of oxygen ion vacancies below PO 2 CRIT affected the rate of sintering.