Preparation of high-performance bismuth yellow hybrid pigments by doping with inorganic oxides

Abstract

High-performance bismuth yellow hybrid pigments based on SiO2, Al2O3 and MgO were successfully fabricated by chemical precipitation followed by annealing at 700°C. Interestingly, the colors of the hybrid pigments depended on the oxide contents, and the optimal yellow value of +92.07 was obtained at an Al2O3/SiO2/MgO mass ratio of 1:0.375:0.750. X-ray diffraction results indicated the formation of pure monoclinic-scheelite-type BiVO4 with high crystallinity, suggesting that the incorporated Si, Al and Mg entered the crystal lattice of BiVO4. Doping with these elements effectively adjusted the band gap of BiVO4, and thus the color of the hybrid pigments could be easily controlled using these oxides. Furthermore, the hybrid pigments also exhibited good suspension properties and chemical stability in acid and alkaline solutions, water and ethanol. Importantly, these pigments were applied in high-grade automotive top finishes and exhibited excellent color and dispersion properties.