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Reaction and Fired‐Property Studies of Cordierite Compositions
Author(s) -
LAMAR R. S.,
WARNER M. F.
Publication year - 1954
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.1151-2916.1954.tb13995.x
Subject(s) - cordierite , talc , differential thermal analysis , crystallization , phase (matter) , mineralogy , perovskite (structure) , materials science , ceramic , thermal expansion , chemical engineering , chemistry , diffraction , crystallography , metallurgy , organic chemistry , physics , optics , engineering
Ceramic bodies approaching the theoretical composition of cordierite were prepared from mixtures of talc and clay; talc, clay, and varying amounts of MgCO 3 ; talc, clay, and alumina; and prochlorite and clay. Additions of BaCO 3 and PbSiO, were made. Differential thermal analysis and X‐ray diffraction methods were used in reaction studies of each composition. Bodies had thermal expansions from 0.344 to 0.109% (25° to 900°C.). BaCO 3 and PbSiO 3 affected thermal expansion. Dielectric properties were improved by additions of BaCO 3 and were markedly improved by additions of both BaCO 3 and PbSiO l . Cordierite started to crystallize at about 1250°. Additions of PbSiO 3 lowered this temperature about 50°C. With sufficient BaCO 3 , the Ba‐C phase, as described by Wisely, crystallized in place of cordierite. The crystallization temperature for the Ba‐C phase was about 1200°C. With insufficient BaCO 3 , both cordierite and Ba‐C formed. Additions of PbSiO 3 reduced the crystallization temperature of the Ba‐C phase by 50°C. and increased the glassy phase. Several of the compositions should haw considerable practical value.