Non-Isothermal Crystallisation of SiO2-MgO-K2O-3CaO·P2O5 Glass Studies by Impedance Spectroscopy


Article Preview

Impedance spectroscopy was used to monitor the non-isothermal crystallisation of a phosphate phase in bulk samples of a glass with the molar composition 0.45SiO2–0.36MgO– 0.09K2O–0.1(3CaO⋅P2O5), intended for biomedical applications. The K+ alkali ions are probably the main charge carriers in glass of this composition [1]. Impedance spectra were obtained as a function of temperature, following non-isothermal heat treatments at 2°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.



Materials Science Forum (Volumes 514-516)

Edited by:

Paula Maria Vilarinho




C. M. Queiroz et al., "Non-Isothermal Crystallisation of SiO2-MgO-K2O-3CaO·P2O5 Glass Studies by Impedance Spectroscopy", Materials Science Forum, Vols. 514-516, pp. 1078-1082, 2006

Online since:

May 2006




[1] C.M. Queiroz, F.M. Figueiredo, M.H. Fernandes and J.R. Frade: Phys. and Chem. of Glasses Vol. 45 (2004) (N. º 2), p.71.

[2] A.L. Oliveira, J.M. Oliveira, R.N. Correia, M.H.V. Fernandes and J.R. Frade: J. Amer. Ceram. Soc. Vol. 81 (1998), p.3270.

[3] C.M. Queiroz, M.H. Fernandes and J.R. Frade: Phys. and Chem. of Glasses, Vol. 43C (2002), p.281.

[4] C.M. Queiroz , S. Agathopoulos, J.R. Frade and M.H.V. Fernandes: Mater. Sci. Forum, Vols. 455-456 (2004), p.383.

[5] C.M. Queiroz, J.R. Frade and M.H.V. Fernandes: Key Engineering Mater., Vols. 254-256 (2004), p.155.

[6] C.M. Queiroz, M.H.V. Fernandes, J.R. Frade, Isothermal crystallisation of a glass from the 3CaO. P2O5-SiO2-MgO-K2O system studied by impedance spectroscopy, (submited to Trans Tech Publications, Switzerland, 2005).

[7] J.A. Augis and J.E. Bennett, J. Therm. Anal., 1978, 13, 283-92.