Catalytic synthesis of hematite-mica pearlescent pigments using a low-temperature method

A novel low-temperature method is described for the direct synthesis of Fe2O3/mica pearlescent pigments with ferric chloride as a precursor and trace Fe(II) as a catalyst which does not require any calcination step. The as-synthesized pigments are characterized in detail by means of different techniques including X-ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy, and colorimetry. The influence of various factors on the transformation from Fe(OH)(3) coating layer to crystalline hematite coating layer is investigated, respectively. Furthermore, this paper studies several critical technological parameters pertaining to the influences on morphology and color properties of the pigments such as the coating temperature and the pH value.