Ceramic pigments obtained by sol-gel techniques and by mechanochemical insertion of color centers in Al2O3 host matrix

Nanocrystalline pigments for ceramic glazes were obtained by mechanochemical insertion of Fe and Ti in an alpha-Al2O3 host matrix (Fe and Ti oxides were reduced by high energy milling with metallic Al with subsequent formation of additional Al2O3 by oxidation of Al(0)). The powders were characterised by XRD, laser granulometry and by surface area and porosity measurements. Sol-gel techniques were also used in order to obtain pigments with pure Al2O3 and Cr or Fe/Ti-doped Al2O3. Pigments were prepared using Al(III)-alkoxides or Al(III)-inorganic salts, obtaining products with different characteristics. Pigments were studied by XRD, surface area and porosity measurements and by the analysis of electrochemical reactivity in aqueous suspensions. Colouring properties of pigments obtained by mechanomaking and by sol-gel techniques were tested in ceramic glazes and their properties were also analysed by insertion in ceramic bodies for glazed gres (porcelain) technology. 23 refs.