Sintering Behavior of LZS Glass-Ceramics

Abstract

Sintering and crystallization behaviors of a LZS glass-powder were investigated by means of thermal shrinkage, differential thermal analysis, X-ray diffraction as well as density and mechanical properties measurements. The melted glass, 9.56Li2O.22.36ZrO2.68.08SiO2(wt%) first was cast into water to provide a frit for milling. The milled glass powder (mean particle size 5.0 µm) was then uniaxially pressed at 100 MPa and the obtained samples were isothermally sintered in the 800-950°C temperature range in air for appropriated time intervals (15-120 min). Sintering was found to start at about 640°C and crystallization took place just after completion of sintering and was almost complete at 920°C. The glass powder compacts crystallized into lithium and zircon silicates so that glass-ceramics with relative densities between 84 and 99% were obtained reaching maximum hardness and bending strength values of 8 ± 0.5 GPa and 214 ± 20 MPa, respectively.