Sintering and crystallization behaviour of nanostructured glass-ceramic glazes derived from industrial solid wastes

摘要

Nanostructured glass-ceramic glazes with smooth and glossy surface textures were synthesized from coal fly ash and blast furnace slag by a simple sintering process. Sintering and crystallization behaviours of the glass-ceramic glaze obtained were investigated by x-ray fluorescence (XRF), differential thermal analysis and thermogravimetry (DTA/TG), powder x-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive x-ray detector (EDX). The results revealed that the amount of main crystalline phases changed with varying sintering temperatures and approached saturation at 1160°C. The main crystalline phase of the glass-ceramic glazes sintered at 1160°C was anorthite, and the anorthite phase content increased with increasing holding times at the crystallization temperature of 956°C. The glass-ceramic glaze obtained had a high Vickers hardness of 9-69 GPa, negligible water absorption, good adherence to the ceramic support, a thermal expansion coefficient of 7.6 x 10~(-6) °C~(-1) and admirable suitability to industrial rapid sintering. The good distribution of spherical anorthite crystals with a uniform size of about 250 nm was responsible for the excellent properties. A possible crystallization mechanism for this glass-ceramic glaze is proposed.