Non Conventional Powder Processing of Cr-Doped Sphene Pigments

The present study is focused on spray and freeze drying procedure for the preparation of Cr-doped sphene pigments (CaSn1-xCrxSiO5, CaTi1-xCrxSiO5) from an aqueous solution of precursor salts plus further calcining the resulting powders. The evolution of the present crystalline phases with applied thermal treatments has been studied by X-Ray Powder Diffraction (XRPD) and thermal analysis (DTA/TG). The powder morphology and chemical composition were analyzed by (SEM). The behaviour of the chromium ion was analyzed by ultraviolet and visible spectroscopy (UV/VIS). The colour efficiency of pigments was evaluated by colorimetric analysis (CIE L*a*b system).