Preparation and characterization of a new lithium-containing glass-ceramic

The aim of this study was to compare the thermal properties and microstruct ure of a new lithium-containing glass-ceramic to those of a dental glass-ce ramic as control. The chemical composition of both control and experimental glasses was determined by electron microprobe analysis. The nucleation and crystallization temperatures were determined by differential thermal analy sis (DTA). The glass specimens were submitted to various heat treatments an d analyzed by X-ray diffraction (XRD) to determine the optimal conditions f or nucleation and growth of the crystalline phases. UV-visible spectroscopy was used to study the nucleation of both glasses. The microstructure of th e experimental glass-ceramic was investigated by scanning electron microsco py (SEM), transmission electron microscopy (TEM), and electron diffraction. Results showed that optimal crystallization of the experimental glass-cera mic was achieved after heat treatment at 950 degrees C for 30 min. The micr ostructure of the experimental glass-ceramic exhibited mica platelets rando mly oriented and highly interlocked. The mica was identified as taeniolite, a lithium-containing tetrasilicic fluormica. (C) 2000 Elsevier Science Ltd .