Effect of crystallization heat treatment on the microstructure and biaxial strength of fluorrichterite glass-ceramics.

Abstract

The purpose of this study was to evaluate the effect of crystallization heat treatment on the flexural strength of potassium fluorrichterite glass-ceramics for biomedical applications. After melting and casting, discs were sectioned from the glass ingots, randomly divided into 10 groups, and heat treated at various temperatures ranging between 890 degrees C and 925 degrees C for various durations. One group was air-abraded after heat treatment. XRD revealed the presence of fluorrichterite and fluormica for all heat-treated groups. SEM confirmed the presence of both fluorrichterite and fluormica crystals. Crystal size increased with temperature and duration of the heat treatment. The mean flexural strength after air abrasion was not significantly different than that of the other groups except the group heat treated at 925 degrees C. The mean flexural strength was maximum after heat treatment at 900 degrees C for 1 h (497.6 +/- 25.5 MPa) and decreased linearly with the longer durations of heat treatment at 900 degrees C.