The thermal properties (glass transformation, T-g, softening, T-s, and exo-peak, T-p, temperatures), and the devitrification behaviour of glasses in the system CaO-Y2O3-SiO2 are reported The T-g, T-p and E(c) results can be explained on the basis of the increased structural rigidity when Ca+2 ions are substituted by Y+3 ions, with the formation of stronger bonds to the oxygen. For the molar ratio of Ca/Si = 0.7 or more, wollastonite is no longer formed; at the same time a new and as yet unidentified phase appears. Surface nucleation occurs preferentially, but, in finely powdered samples, which soften and sinter before devitrifying, surface nuclei behave virtually as bulk nuclei.
Thermal-properties and Devitrification Behavior of (2-x)cao-center-dot-x/3y(2)o(3)center-dot-2sio(2) Glasses / Costantini, Aniello; Branda, Francesco; A., Buri. - In: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY. - ISSN 0955-2219. - ELETTRONICO. - 15:(1995), pp. 1025-1029. [10.1016/0955-2219(95)00068-6]
Thermal-properties and Devitrification Behavior of (2-x)cao-center-dot-x/3y(2)o(3)center-dot-2sio(2) Glasses
COSTANTINI, ANIELLO;BRANDA, FRANCESCO;
1995
Abstract
The thermal properties (glass transformation, T-g, softening, T-s, and exo-peak, T-p, temperatures), and the devitrification behaviour of glasses in the system CaO-Y2O3-SiO2 are reported The T-g, T-p and E(c) results can be explained on the basis of the increased structural rigidity when Ca+2 ions are substituted by Y+3 ions, with the formation of stronger bonds to the oxygen. For the molar ratio of Ca/Si = 0.7 or more, wollastonite is no longer formed; at the same time a new and as yet unidentified phase appears. Surface nucleation occurs preferentially, but, in finely powdered samples, which soften and sinter before devitrifying, surface nuclei behave virtually as bulk nuclei.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
