Evolution of binary Fe2O3/SiO2 coating layers on the surfaces of aluminum flakes and the pigmentary performances

Binary Fe2O3/SiO2-coated aluminum pigments were prepared by chemical liquid deposition method using tetraethyl silicate (TEOS) and FeCl3 as the precursors of SiO2 and Fe2O3, respectively. The chemical structure and the evolution mechanism of the binary Fe2O3/SiO2 coating layers were investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, and scanning electron microscopy techniques. The binary Fe2O3/SiO2 coating layers were anchored at aluminum flake surfaces via SiOAl and FeOSi bonds. The anticorrosive performance of the SiO2-coated aluminum flakes was significantly improved as compared with the naked aluminum flakes, indicating that SiO2 coating layers were densely and tightly formed on the surfaces of aluminum flakes. The pigmentary performances of the binary Fe2O3/SiO2-coated aluminum samples were analyzed by CIE, showing that yellow and red colored aluminum-based pigments were achieved by varying the Fe2O3 loading on SiO2-coated aluminum flake substrates.