Effect of Various Opacifiers on Color Parameters and Gloss of Glazed Tiles

This study was designed to compare the effect of various opacifiers of zircon and andalusite on color parameters and gloss of tile samples. Although zircon is one of the most important opacifying agents that applied to make the engobe opaque, it is interesting to find a cost-effective alternative for that in ceramic industry. At the present work, the whiteness degree was applied to determine the degree of opacification. The effect of used opacifiers on color appearance of glaze was studied by calculating the color parameters CIEL*a*b*color space. Besides, the parameters of specular gloss, reflection haze and distinctness of image were determined to show the effect of used opacifiers on geometric appearance of glaze. The results showed that the nature and particle size distribution of opacifier as well as the grinding of engobe before the andalusite application play important role. In addition, it was illustrated that using andalusite instead of zircon as opacifying agent is caused the color appearance of glaze to shift from white shade to yellowish one. The results of gloss, reflection haze and distinctness of image pointed out that the geometric appearance properties of glaze are mainly affected by its nature than the applied opacifier. The confirmation of the obtained results was checked with the optical microscopic images.