Corrosion Protection on the Surface of Waterborne Aluminum Pigments by Sol-Gel Method

Abstract

The aluminum pigments were coated with SiO₂ by sol-gel method using tetraethoxysilane as precursors to improve their stability. The effects of formulation factors, such as dosage of tetraethoxysilane, water and ammonia solution, reaction temperature and reaction time on the corrosion protection efficiency and coater gloss were investigated. The results showed that under the optimum conditions, the corrosion protection efficiencies reach 98.9 % and 99.1 % in acid media of pH 1 and alkaline media of pH 11, respectively and the coater gloss is 86.5. By the characterization of scanning electron microscopy, Fourier transformation infrared spectroscopy and X-ray diffraction, SiO₂ was proved to be coated on the surface of the as-prepared waterborne aluminum pigments and the reaction conditions were optimized.