Study on silica coated chrome oxide green pigment and its performance

Abstract

AbstractIn this study, sodium silicate (Na2SiO3) was used as the precursor of SiO2 to prepare Cr2O3/SiO2 composite pigments. First, using cetyltrimethylammonium bromide to surface modification of the chromium oxide green pigment to make the surface of the particles positively charged. The negatively charged SiO2 sol coats the surface of the pigment particles through electrostatic attraction. Then use HCl solution acid to precipitate SiO2, and finally get Cr2O3/SiO2 composite pigment. The structure of the modified pigment was analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size distribution analysis, and X‐ray diffraction (XRD) characterization. The influence of silica coating on the tinting strength, dispersibility of pigment in water, and hiding power of the chromium oxide green pigment were further investigated. The results demonstrate that SEM, TEM, and particle size analysis shows that this experimental method can obtain a good silica coating. When the coating quantity is 30%, the full coating of chromium oxide green by silica is achieved. According to the XRD analysis before and after the chromium oxide green coating, as the reaction temperature increases, the intensity of the SiO2 diffraction peak becomes larger and the crystallization effect becomes better. In the test of pigment performance, it can be concluded that the coloring power, hiding power, and dispersibility of Cr2O3/SiO2 composite pigments are better than those of uncoated chromium oxide green pigments.