Low water absorption and pyroplastic deformation of alumina‐strengthened porcelain with petalite and Gairome clay

The pyroplastic deformation (PD) of porcelain is a key issue for reducing production loss. In this study, material design to realize both low a water absorption (WA) and low PD in alumina-strengthened porcelain, which have a trade-off relationship, was proposed. In this porcelain material design, a rigid microstructure composed of entangled needle-like mullite crystals is formed by the addition of Gairome clay, which has the positive effect of suppressing PD but negatively affects densification. This was balanced by the controlling the amount and viscosity of the liquid phase in the porcelain fired at elevated temperatures with optimized quantities of added petalite and Gairome clay to obtain a low WA and low PD. As a result, a WA below 0.5% and PD index below 1.5 x 10(-6) mm(-1)in a wide firing temperature range from 1194 to 1384 degrees C were obtained for porcelain containing Amakusa clay at 37.8 mass%, Gairome clay at 17.0 mass%, petalite at 13.7 mass%, and alumina at 31.5 mass%.