Volume 1 Issue 3
Authors: Hiroaki Onoda; Takeshi Sakumura
Abstract: In this paper, we report the preparation of trivalent iron phosphates in aqueous solution and its use as inorganic yellow pigment. Because cerium phosphate is insoluble in acidic and basic solution, the substitution of cerium cation was tried to improve the acid and base resistance of iron phosphate pigments. The cerium substituted iron phosphates were prepared from phosphoric acid, trivalent iron nitrate, and ammonium cerium nitrate solution. The influence of tetravalent cerium cation was studied on the chemical composition, particle shape and size distribution, specific surface area, color, acid and base resistance of the precipitates and their thermal products. The cerium ratio in precipitates was lower than that in preparation process. Samples had a certain degree of amorphous phase in spite of the Fe/Ce ratio, the addition of H2O2, and the heating temperatures. The color of these phosphate pigments was from dark yellow to brownish yellow. The acid resistance of iron phosphate prepared with H2O2 improved by the substitution with cerium.
Keywords: Iron Phosphate; Pigment; Cerium Substitution; Acid and Base Resistance