Effect of Soaking Time on the Crystal Size and Microstructure of Willemite Crystal Glazes

Abstract

This research aimed to study the effect of soaking time on the crystal size and microstructure of willemite crystal. The glaze mixtures were glazed on the samples of clays and fired at temperatures of about 1250°C. Later, the temperature was decreased to 1100°C and was soaked at this level for 2, 3 and 4 hours for crystallization and the growing of crystal. The mineral composition of the glaze mainly contained of willemite and quartz. The microstructure of the glazed crystals after sintering was needle shaped and had spherical growth. The effect of soaking time on the crystal size of willemite was observed. The crystal size was increased when soaked at 2, 3, and 4 hours, respectively.