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Further Investigation of the Stabilization of β‐Cristobalite
Author(s) -
Thomas Elizabeth S.,
Thompson John G.,
Withers Ray L.,
Sterns Meta,
Xiao Yuehui,
Kirkpatrick R. James
Publication year - 1994
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.1151-2916.1994.tb06956.x
Subject(s) - tridymite , cristobalite , crystallography , phase transition , phase (matter) , fourier transform infrared spectroscopy , chemistry , materials science , mineralogy , chemical engineering , thermodynamics , metallurgy , organic chemistry , quartz , physics , engineering
Chemical stabilization of β‐cristobalite has been achieved using two methods: (1) incorporating “stuffing” cations Na, Ca, Cu, and Sr into the cavities in the tectosilicate framework, as previously reported, and (2) without “stuffing” cations, by substituting AlPO 4 into the framework. XRD, TEM, FTIR, DSC, and solid‐state variable‐temperature 29 Si NMR confirm that stabilization occurs by both methods. Dynamic disorder, characteristic of the β‐cristobalite structure above the α↔β phase transition, was observed via TEM in the NaAlO 2 ‐, CaAl 2 O 4 ‐, and CuAl 2 O 4 ‐stabilized cristobalites at room temperature. For AlPO 4 ‐stabilized material intergrowths of AlPO 4 regions with a tridymite‐type structure suppress the β‐ ↔α‐cristobalite phase transition.