Characterization of Pearl Luster Pigments

Abstract This paper presents current developments in pearl luster pigments. After a short introduction on the application of pigments, the synthesis and characterization of a ZrO₂/SiO₂ based pearlescent pigment will be described. The applied methods for characterization were ex situ x‐ray diffraction (XRD) of dried and calcined pigment powders, in situ XRD in a temperature range from 100°C up to 850°C and transmission electron microscopy (TEM) of thin cross‐sections. The XRD measurements were used for phase analysis, determination of cell parameters and average crystal grain sizes. A special preparation method was developed for TEM cross section specimens for platy like pigment particles. The microstructure, the interface between substrate and coating material and the particle sizes are described with high resolution TEM pictures of cross section specimens. The basic interest is the behaviour of the zirconium dioxide coating during sintering in order to achieve a condensation of the film without any further crystal grain growth.