Corrosion behavior of HVOF sprayed 304 stainless steel coating on 6061 substrate in 3.5 wt% NaCl solution

Abstract

This study aimed to improve the corrosion resistance of lightweight material surfaces by applying a 304 stainless steel coating (304SSC) onto 6061 aluminum alloy using high-velocity oxygen-fuel (HVOF) spraying. The phase composition, microhardness, microstructure, and long-term corrosion behavior of the HVOF-sprayed 304SSC in 3.5 wt% NaCl solutions were analyzed through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and an automated micro-hardness testing system. The findings indicated that the corrosion resistance of the coatings improved as the number of deposited layers increased. Moreover, the coatings that displayed the highest resistance to chloride ion attack in long-term immersion experiments also effectively prevented galvanic coupling. The enhanced corrosion resistance was attributed to reduced porosity, increased densification, and enhanced mechanical stability of the coatings.