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Transformation of Quartz to Tridymite in the Presence of Binary Silicate Liquids
Author(s) -
MADDEN GERALD I.,
VLACK LAWRENCE H.
Publication year - 1967
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.1151-2916.1967.tb15146.x
Subject(s) - tridymite , cristobalite , eutectic system , metastability , silicate , quartz , transformation (genetics) , phase (matter) , isothermal process , mineralogy , thermodynamics , nucleation , chemistry , stishovite , materials science , chemical engineering , crystallography , metallurgy , organic chemistry , microstructure , biochemistry , gene , physics , engineering
The isothermal transformation rates for quartz to tridymite were studied in the presence of binary silicate liquids between the eutectic temperature and 1470°C. Oxide pairs included Na 2 O‐SiO 2 , PbO‐SiO 2 , FeO‐SiO 2 , and Cu 2 O‐SiO 2 . Micrographic and X‐ray analytical procedures were used. Transformation was most rapid at intermediate temperatures, thus providing typical TTT curves. The rates increased as the liquid contents of the binary pairs were increased. Transformation was more rapid for the pairs which had higher SiO 2 contents in their equilibrated liquids. Transformation proceeded as a solution‐reprecipitation reaction. Initially, metastable cristobalite precipitated more rapidly than the tridymite; however, it redissolved and eventually disappeared, leaving only tridymite as the solid phase. An empirical equation was adapted to the transformation.