Double-layer modification of water-based aluminum with SiO₂ and polyacrylic acid by sol-gel process and in situ polymerization

Abstract

A double-layer aluminum consisting of an aluminum core and a shell of SiO₂ and polyacrylic acid was synthesized. This modified aluminum was used to improve the corrosion resistance and dispersive property of aluminum in waterborne media. TEM, FTIR, XPS, and EDX determination showed that PAA and SiO₂ were coated on the surface of aluminum. Evolved hydrogen detection showed that the corrosion resistance of composite particle had been markedly improved. Maximum corrosion inhibition efficiency of SiO₂ coated aluminum (SiO₂@Al) was 95.1% while that of double-layer coated aluminum (PAA/SiO₂@Al) was 98.8%. Meanwhile, polyacrylic acid layer improved the agglomeration of aluminum significantly. According to the dispersibility test, the particle size of 50% volume fraction [d(0.5)] of aluminum, SiO₂@Al and PAA/SiO₂@Al were 42, 53, and 34 μm, respectively.

Keywords

flaky aluminum / water-based pigments / polymer coating / alkaline corrosion

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