Effect of feldspar particle size on the porous microstructure and stain resistance of polished porcelain tiles

The final porosity of porcelain tiles results from the incomplete densification of the material during the stages of processing. The use of raw materials such as feldspar, with a high potential for forming liquid phase during sintering, contributes to eliminate porosity when a suitable heating cycle is employed. This paper presents the results of a study that investigated the effect of the particle size distribution (PSD) of feldspar on the formation of pores in the green compact and the final product, using stain resistance as an evaluation parameter of surface porosity. To this end, the feldspar used in a standard paste of technical porcelain was milled under different conditions to produce the desired changes in its PSD. The groundbreaking results indicate that slight changes in the milling conditions of feldspar can significantly alter the porous microstructure of the material and the stain resistance of the polished tile surface.