Incorporation of Metal Oxides on Mica Flakes as Green Pearlescent Pigments: Preparation and Analysis

Pearlescent pigments represent a variety of pigments that can generate pleasant optical appearances in the system because of their ability of easy parallel orientation of a large number of platelet-like particles. In the present work, the green pearlescent pigments based on mica (biotite) and mica-titania flakes covered with a thin film of nickel oxide have been prepared by novel methods via the homogeneous precipitation of nickel acetate with sodium/potassium hydroxide, and in the presence of mica (biotite), titania, ammonium molybdate or mica-titania flakes. The synthesized pigments were characterized by means of X-ray diffractometery (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-Ray fluorescence (XRF) analyses. By comparing the XRD pattern of synthesized pigments with the mica based pattern, it is clear that the structure of the support does not change due to the layering on these bases. The XRF analysis shows that the nickel compound is layered well on the mica at 8.823 %. The quantity and quality of the pigments produced by methods 1 and 2 were approximately the same. Consequently, to make commercial savings, method 1 was recommended for the preparation of the metallic pearl pigments and mica was known as the best support for the production of the pearlescent pigments by the introduced method. Furthermore, the TGA/DSC curve showed that the introduced pigments were stable up to 200 °C. The results showed good chemical resistance and pearl luster effects for the produced pigments.