Non-isothermal crystallisation of SiO2-MgO-K2O-3CaO center dot P2O5 glass studies by impedance spectroscopy

authors	Queiroz, CM; Fernandes, MHV; Frade, JR
editors	Vilarinho, PM
nationality	International
journal	ADVANCED MATERIALS FORUM III, PTS 1 AND 2
author keywords	glass crystallisation; electrical conductivity; impedance spectroscopy; whitlockite
abstract	Impedance spectroscopy was used to monitor the non-isothermal crystallisation of a phosphate phase in bulk samples of a glass with the molar composition 0.45SiO(2)-0.36MgO-0.09K2O-0.1(3CaO(.)P(2)O(5)), intended for biomedical applications. The K+ alkali ions are probably the main charge carriers in glass of this composition [I]. Impedance spectra were obtained as a function of temperature, following non-isothermal heat treatments at 2 degrees Cmin(-1). It is shown that suitable analysis of impedance spectra can be used to evaluate the crystallization peak of a orthophosphate phase, Ca9MgK(PO4)(7). Results obtained by this method are comparable to those obtained by differential thermal analysis (DTA) of the corresponding glass frits. Impedance spectroscopy is thus suitable to study the crystallization of bulk samples, and can be used both with variable temperature and under isothermal conditions.
publisher	TRANS TECH PUBLICATIONS LTD
issn	0255-5476
year published	2006
volume	514-516
beginning page	1078
ending page	1082
web of science category	Materials Science, Multidisciplinary
subject category	Materials Science
unique article identifier	WOS:000238056400215