Effect of cordierite crystallization on the water absorption and pyroplastic deformation of an alumina-strengthened porcelain that contains fine talc

摘要

The effect of cordierite crystallization on the densification and pyroplastic deformation (PD) of alumina-strengthened porcelain that contains talc is examined herein. During firing at a relatively low temperature below 1200 °C, the addition of fine talc powder with a mean diameter of approximately 7 μm is more effective in promoting the liquid phase sintering of the porcelain through an increase in the amount of the low-viscosity liquid phase due to Mgsup2+/sup doping than the addition of a coarse talc powder with a mean diameter of approximately 14 μm. Beyond the firing temperature, cordierite crystallization that is accelerated by the fine talc addition suppresses the PD of the porcelain through a decrease in the amount and an increase in the viscosity of the liquid phase due to the transfer of Mgsup2+/sup from the liquid to the cordierite crystals. As a result, a decrease in the water absorption (0.5%) and PD index (1.5 × 10sup?6/sup mmsup?1/sup) is realized for the porcelain with 32 mass % addition of the fine talc powder over a relatively wide firing temperature range from 1194 to 1336 °C.