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Rapid Formation of the 110 K Phase in BI‐Pb‐Sr‐Ca‐Cu‐O through Freeze‐Drying Powder Processing
Author(s) -
Song KangHo,
Liu Huakun,
Dou Shixue,
Sorrell Charles C.
Publication year - 1990
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.1151-2916.1990.tb09830.x
Subject(s) - sintering , mixing (physics) , phase (matter) , materials science , mineralogy , chemical engineering , freeze drying , liquid phase , analytical chemistry (journal) , metallurgy , chemistry , chromatography , thermodynamics , physics , organic chemistry , quantum mechanics , engineering
Three techniques for processing Bi‐Pb‐Sr‐Ca‐Cu‐O (BPSCCO) powders were investigated: dry‐mixing, sol‐gel formation, and freeze‐drying. It was found that sintering for 120 h at 850°C is required to form nearly single‐phase (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10‐y by dry‐mixing, whereas sintering for 30 h at 840°C was sufficient to form the 110 K (2223) phase when freeze‐drying was used. The sol‐gel route was found to be intermediate in efficiency between these two techniques. Freeze‐drying provided highly reactive, intimately mixed, and carbon‐free precursors. The presence of carbonates in the uncalcined powders was the major cause of phase segregation and sluggishness of the 110 K phase formation.