Corrosion protection of pure aluminium and aluminium alloy (AA7075) in salt solution with silane-based sol-gel coatings

摘要

Sol-gel films of tetraethoxysilane (TEOS), phenyltriethoxysilane (PTES) and phenyltrimethoxysilane (PTMS) were prepared on aluminium and aluminium alloy AA7075 and characterised. The corrosion inhibition properties of uncoated and coated specimens were evaluated with potentiodynamic polarisation scan, linear polarisation resistance and open circuit potential measurements. With scanning electron microscopy and optical microscopy effects of the sol-gel coating were shown. Weight loss measurements were performed at different pH-values. More hydrophobic coatings as PTMS show a considerably better corrosion inhibition capacity as compared to the capacity provided by less hydrophobic ones as TEOS and PTES.