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2223 Phase Formation in Bi(Pb)─Sr─Ca─Cu─O: III, The Role of Atmosphere
Author(s) -
Chen Yan Ling,
Stevens Ronald
Publication year - 1992
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.1151-2916.1992.tb05553.x
Subject(s) - oxidizing agent , annealing (glass) , sintering , phase (matter) , materials science , atmosphere (unit) , oxygen , analytical chemistry (journal) , precipitation , atmospheric temperature range , reducing atmosphere , argon , superconductivity , mineralogy , metallurgy , chemistry , thermodynamics , environmental chemistry , physics , organic chemistry , quantum mechanics , meteorology
The formation of second phases during the preparation of the 2223 phase and their stability in the Bi system under various annealing temperatures and atmospheres have been studied. The 2201 precipitates developed at ∼830°C, and their conversion to the 2223 phase can be completed in the temperature range 810°C ≤ T < 830°C. A Ca 2 PbO 4 ‐like phase can precipitate from the liquid phase at ∼830°C during cooling. A (Sr,Ca) 14 Cu 24 O 41 phase is usually found accompanying the synthesis of the 2223 phase. This secondary phase is stable in an oxidizing atmosphere but can be eliminated by annealing under a low oxygen atmosphere or by choosing a suitable starting composition and set of sintering conditions. The precipitation of Ca 2 PbO 4 ‐like phase can be avoided by using a relatively fast cooling rate. Unlike the YBa 2 Cu 3 O x superconductor, the 2223 phase can be stable under a wide range of atmospheres, such as argon, air, and oxygen.