Synthesis of Cobalt-Substituted Manganese Phosphate Purple Pigments.

Some manganese phosphates are known as violet pigments. In this study, pigments in which manganese was partially replaced with cobalt and aluminum was replaced with lanthanum and cerium were synthesized with a heating method to obtain pigments with a more reddish color. The obtained samples were evaluated in terms of chemical composition, hue, acid and base resistances, and hiding power. Among the samples examined, the samples obtained in the Co/Mn/La/P system were the most vivid. The brighter and redder samples were obtained by prolonged heating. Furthermore, prolonged heating improved the acid and base resistance of the samples. Finally, the substitution of manganese for cobalt improved the hiding power.