Effects of alumina and white fused alumina addition on technological properties of transparent floor tile glazes

Abstract

In ceramic tile manufacturing, α-Al2O3 is the main type of alumina used in ceramic body and glaze formulations. It acts as an opacifer in porcelain tile bodies and as a matting agent in glazes. White fused alumina (WFA) is produced by fusing calcined alumina in an electric arc furnace under carefully controlled conditions. It is generally preferred in ceramic foor tile glazes in order to increase abrasion resistance. The aim of this study was to establish a better understanding of how alumina and WFA addition afects the thermal behavior, microstructural evolution and aesthetic properties of transparent foor tile glazes. The results showed that both alumina and WFA increased the sintering and melting temperatures of the standard commercial glaze. Corund was detected in the main phase with WFA addition in tile glazes. There were no other crystalline phases formed since WFA did not react with glassy phase. This behavior can be attributed to higher refractoriness of fused alumina. Smoother surface and homogenous structure were observed in the glazes with WFA addition. However, anorthite and corund phases were detected in the glazes with alumina addition. High crystallization glazes with rough surfaces were observed in these glazes. Alumina was found to be more efective to increase opacity and reducing glossiness compared WFA addition.