Preparation and characterization of colored aluminum pigments Al/SiO2/Fe2O3 with double-layer structure

Gold-colored aluminum pigments with double layer structure Al/SiO2/Fe2O3 were prepared successfully through coating Fe2O3 layer on aluminum flake by traditional wet chemical method. The reaction conditions were optimized according to the coating efficiency (CE), percentage of coating (PC) and flop index (FI) values. It was found that at the optimum conditions, the coating efficiency, percentage of coating and flop index values are 95.51%, 31.43% and 13.92 respectively. SEM and AFM were used to characterize the surface morphology of the Al/SiO2/Fe2O3 pigments and the results show that the surface has a heterogeneous nanoparticle layer and the average roughness is 34.8 nm. The optical properties were investigated in detail by using the five angleʹs spectrophotometer revealing that Al/SiO2/Fe2O3 pigments have angle-dependent optical effects and at least have three different colors from the five angles.