Preparation and characterisation of pigments based on mica coated with rare earth oxides

Abstract

Muscovite from a Brazilian natural source was beneficiated using knife mills and an ultrasound treatment. It was possible to achieve mica with a particle size of below 100 and above 45 lm and a thickness of between 0.5 and 1 lm. This product could be used for the synthesis of intensely coloured pearlescent pigments based on muscovite covered with rare earth oxides (CeO 2 , PrO 2 and Ce 0.95 Pr 0.05 O 2 ). Pigments were prepared by hydrolysis and characterised by X-ray diffraction, thermal analyses (thermogravimetric ⁄ differential thermal) and scanning electron microscopy (MeV). The colour of the resulting pigments was analysed using the CIELab method, including a pearlescence index, and it showed the following colours: mica-CeO 2 , yellow; mica-PrO 2 , black; mica-Ce 0.95 Pr 0.05 O 2 , orange.

Preparation and Characterization of La₂Ti₂O₇:Pr³⁺-Coated Pearlescent Pigment with Fluorescent

“…Usually, pearlescent pigment is prepared by chemical liquid phase deposition method, where the flakes materials are chose as the base and coated with one-layer or multi-layer of metal oxide with high refractive index, such as titanium dioxide, ferrous oxide, rare-earth oxides and so on [3,4]. As to fluorescent materials, they are mostly synthesized by the solid phase method.…”