Sol-gel coatings with hydrothermal hydroxylation as pre-treatment for 2198-T851 corrosion protection performance

2198-T851 alloy samples were anodized in tartaric-sulfuric acid (TSA) and pretreated by hydrothermal hydroxylation, then protected by application of a hybrid sol-gel coating. The sol-gel coating was prepared using a solution obtained tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). The morphology and thickness of the film were evaluated by field emission scanning electron microscopy (FE-SEM). The corrosion resistance and corrosion mechanism of the film were analyzed by electrochemical testing and Long-term corrosion resistance testing. The results show that the sol-gel film preparing with hydrothermal hydroxylation as pre-treatment were smooth and dense. The treatment with hydrothermal hydroxylation and the hybrid sol-gel improved barrier properties and long-term corrosion resistance of 2198-T851 alloy.