Active corrosion protection coating for ZE41 magnesium alloy created by combining PEO and sol-gel techniques

Abstract

An active protective coating for ZE41 magnesium alloy was produced by sealing an anodic layer, loaded with 1,2,4-triazole, with a sol-gel film. An anodic oxide layer was formed using PEO in a silicate-fluoride alkaline solution. This thin (1.8 μm) porous PEO layer was impregnated with corrosion inhibitor 1,2,4-triazole and sealed with a silica-based sol-gel film modified with titanium oxide. For the first time it was demostrated that this relatevelly thin PEO-based composite coating reveal high barier properties and provide superior protection against corrosion attack during 1 month of continuous exposure to 3% NaCl. Scanning vibrating electrode technique showed sharp decrease (100 times) of corrosion activity in micro defects formed in 1,2,4-triazole doped composite coating, when compared to blank samples.