Porcelain tile microstructure: implications for polishability

The present study examines the influence of porcelain tile microstructure on tile polishability and polishing efficiency. A range of different fired porcelain tile microstructures was obtained by varying the quartz particle size and content in the starting composition, and the peak firing temperature.The polishability of these porcelain tile specimens was evaluated with a tribometer designed to simulate the industrial polishing operation, using cement-matrix silicon carbide abrasive tools. The wear rates of both the tile samples and the abrasive tools were measured. A new parameter, termed ‘polishing efficiency’, was defined as the ratio of tile specific wear rate to pin specific wear rate.Quartz particle size and content in the starting composition, as well as peak firing temperature, strongly affected the fired tile microstructure, and hence the polishability. When the firing temperature lies below the optimum value (at which porosity is minimised) the polishing efficiency increases, while the polished surface quality decreases (i.e. porosity rises). Quartz particle size and content should be minimised in the starting composition to achieve maximum polished surface quality and polishing efficiency.