Color effects of novel flake α-Al2O3-based pearlescent pigments

In this work, the color effects of novel Fe2O3/flake α-Al2O3 pearlescent pigments prepared with different Fe salts and colorant dosages were investigated. First, Fe2O3/flake α-Al2O3 pearlescent pigments with hexagonal flakes were successfully prepared by liquid-phase deposition. Second, the color effects of these pearlescent pigments were systematically investigated by changing the Fe salt and its dosage. The surface morphology, elemental distribution, and phase structures of the pigments were comprehensively characterized by scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffractometry. The results show that the color intensity of the pigments is affected by the Fe salt and its dosage. In addition, pigments prepared from different Fe salts show different colors. The color of the pigments was found to gradually deepen with increasing colorant dosage, and the pearlescent pigments obtained showed rich color effects. Therefore, different colors can be obtained by varying the colorants and their dosage, and this in turn enables the controllable preparation of different colors. Finally, the possible formation mechanism of the color effects was considered. Due to the different hydrolysis ability of the different colorants, the amount of Fe(OH)3 generated by hydrolysis is different for each; thus, different coating ratios are obtained, resulting in different color effects. The results of this study provide a strong reference for the preparation of high-end pearlescent pigments and the modulation of their colors.