Lightening of alumina-strengthen porcelain by controlling porosity

Tableware of alumina-strengthened porcelain are heavy and may break by mechanical impact other tablewares consisting of quartz-base porcelain due to its elevated specific gravity, depending on or-alumina content. Starch particles were introduced as temporary organic additives into the starting slurry for alumina strengthened porcelains, and the effect of size distribution of isolated pores and porosity formed in the fired bodies was examined, in order to decrease the specific gravity with minimum strength degradation. In glazed bodies added with 11.5 mass% of corn starch particles finer than 20 mu m, a bending strength of 180 MPa was obtained, despite a decrease of about 18% in bulk density, and the density coincided with those of ordinary quartz-base porcelains, 2.35 x 10(3) kg . m(-3).