Inhomogeneity of porcelain body formed by pressure casting method

Abstract

Kutani ware is characterized by its overglaze decorating style using Japanese colors. In Kutani industry, it is empirically known that Japanese colors have the tendency of peeling off more often when the body is formed by pressure casting method. In this study, inhomogeneity of porcelain body is examined after measuring the body with applying a X-ray fluorescence analysis to detect the change of chemical composition in the layers from the surface to the center of the body. Converting the obtained values of chemical composition into mineral composition, it was found out that the body formed by pressure casting method becomes highly inhomogeneous; high amounts of clay minerals was observed at the surface and at 1040 μm from the surface, a composition almost the same as the slip within a layer 300-960 μm from the surface, and less clay minerals in the center layer. The result of this experiment also shows that it is possible to improve the homogeneity of the body by controlling the water content of the slip in order to achieve a less mobility of the clay particles.