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Glassy Phase in Alumina–Silica Ceramic Shell Molds
Author(s) -
Zhou Wancheng,
Zhang Litong,
Fu Hengzhi
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.tb05445.x
Subject(s) - devitrification , mullite , materials science , crystallization , phase (matter) , chemical engineering , mineralogy , ceramic , analytical chemistry (journal) , composite material , chemistry , organic chemistry , chromatography , engineering
Variation of the amount and the composition of the glassy phase in high‐purity Al 2 O 3 ‐SiO 2 shell molds and the crystallization of the glassy phase have been studied. The results indicate that the two main modes of transformation from a glassy phase to a crystalline phase during firing are (1) formation of mullite through a chemical reaction and (2) devitrification of the glassy phase that comes from the original materials. The transformation is mainly influenced by the S/ ( A + S ) value ( A and S are the weight percentages of Al 2 O 3 and SiO 2 , respectively), the Na 2 O content, and the firing temperature. Low S /( A + S ), low Na 2 O, and high firing temperature are favorable to the transformation.