Synthesis and characterization of the pearlescent pigments based on mica deposited with SiO2, AlN and TiO2: First report of its dielectric properties

SiO2, AlN and TiO2 deposited mica based pearlescent pigments were synthesized by using the chemical reduction method in aqueous solution. The optical and dielectric properties of mica@SiO2, mica@AlN, and mica@TiO2 were investigated. The comprehensive analysis of the obtained pigments was evaluated by determining their thermal, optic and dielectric properties. The surface structure, bonding, and phase properties were obtained by field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD), respectively. The thermal and optical properties were determined by thermogravimetric analysis (TGA) and UV-vis absorbance spectra. For the first time, the dielectric and electromagnetic wave absorption properties of pearlescent pigments were investigated. The mica@TiO2 pigment exhibited higher UV-vis absorption than those of mica@SiO2, and mica@AlN. Besides, the presence of TiO2 has tremendously increased the dielectric values. The electromagnetic (EM) wave absorption of mica@TiO2 achieved a minimum R-L, value of -16.7 dB at a thickness of 3.4 mm. This study presented a new report for dielectric and EM absorption of mica@SiO2, mica@AlN, and mica@TiO2 pigments.