Effect of LZSA glass-ceramic addition on pressureless sintered alumina. Part I: Grain growth

Abstract

The aim of this study was to evaluate the effect of an 11.6Li2O-16.8ZrO2-68.2SiO2-3.4Al2O3 (LZSA) glass ceramic on the grain growth of alumina obtained by pressureless sintering. Three contents of the LZSA glass ceramic (7, 15, and 21 vol%; mean particle size of 1.52 μm) and three types of alumina (mean particle sizes of 0.5, 1.7, and 2.8 μm) were used. The powder compositions were formed by cold pressing. The samples (5 mm × 5 mm × 13 mm) were sintered in an optical dilatometer. The grain size and morphology were evaluated by scanning electron microscopy. The results show that elongated alumina particles were obtained for the investigated composites compared with pure alumina because of the LZSA addition. The grain growth of alumina was less pronounced at higher LZSA contents. High relative densities were obtained for higher LZSA contents at lower temperatures and holding times compared with pure alumina.