Evaluation of the water absorption and pyroplastic deformation of alumina-strengthened porcelain with talc-addition

Abstract

The water absorption (WA) and pyroplastic deformation (PD) of alumina-strengthened porcelain with talc-addition is examined to develop porcelain with optimized properties for a wide range of firing temperatures. An increase in talc amount enhances the porcelain densification, i.e. decreases WA and the increase in sintering shrinkage which accelerates PD, because it leads to an increase in the amount of liquid phase with a low viscosity during firing. On the other hand, talc and Gairome clay addition yields rigid crystalline microstructures in the glass matrix of the porcelain, which suppresses PD. As a result, optimized properties, i.e. WA less than 0.5% and pyroplastic deformation index less than 1.5 × 10⁻⁶ mm⁻¹, are realized in porcelain with 2 mass % talc addition in a wide firing temperature range from 1240 to 1384 °C.