Effect of Microcracks on the Corrosion Behaviour of Fe-based amorphous coatings in Chloride Solutions

摘要

In this paper, the influence of microcracks on the corrosion behaviour of Fe-based amorphous coatingon 304 stainless steel in 3.5 wt.% NaCl solution was investigated. Results show that microcracksdeteriorate the corrosion resistance. The corrosive solution can penetrate into the microcracks,resulting in the direct corrosion of the substrate. Furthermore, the pitting potential of the substrate atthe coating–substrate interface is apparently lower than that of the uncoated substrate, which isascribed to the crevice corrosion caused by through-microcracks. As a result, the coated substrate ismore prone to corrosion than the uncoated substrate. The microcracks can be effectively sealed byaluminium phosphate sealant, which improves the protectiveness of amorphous coating.