Superior Corrosion-Resistant Fe-Based Amorphous Alloy Coatings with Controllable Chemical Inhomogeneity by Electrochemical Etching

Abstract

This work investigated the strategies to manipulate the corrosion performance and the underlying mechanisms of thermal-sprayed Fe-based amorphous alloy coatings (AACs). Results unveiled that the chemical inhomogeneity of AACs was accompanied by structural defects (e.g. pores, intersplats, and crystals), which were susceptive to the pitting. The union of electrochemical etching and sealing enhanced the corrosion behavior of AACs, as the former enhanced the passivation performance via controlling the etchant and etching time to improve the chemical inhomogeneity, while the latter filled the structural defects to further overcome their damage to corrosion behavior. The electrochemical responses manifested that the optimal etching condition was to be etched in 1 mol/L HCl solution for 30 min. The superior corrosion-resistant Fe-based AACs herein significantly raised their application potential in corrosive environments.

Keywords: amorphous alloy coating, corrosion resistance, Passive film, chemical inhomogeneity, electrochemical etching, sealing