Abstract: The aim of the optimization of the technological process was to coat the surface of the pigment in a controlled manner and to supress photoactivity in the titanium dioxide (TiO₂) pigment. As part of this research, a systematic approach to TiO₂ pigment surface treatment with alumina was conducted. Surface treatment with alumina plays a significant role in the improvement of TiO₂ properties (e.g. weather resistance and photostability).This research encompasses a raw material analysis and process conditions study. Sodium aluminate and aluminium sulphate were used as a source of alumina hydroxide. The effectiveness of surface treatment was determined using scanning-transmission (STEM) and transmission (TEM) electron microscopy. The photoactivity of pigmentary TiO₂ was determined before and after surface treatment. A controlled surface treatment process resulted in pigmentary TiO₂ particles with uniform amorphous layers, which supressed the photoactivity of the pigment.

Keywords: Titanium dioxide, Surface treatment, Coatings, Alumina, Photo activity.