Effect of sealing treatment on corrosion behaviours of arc sprayed zinc coatings

Abstract

In this work, a simulated corrosion electrolyte was employed in order to assess the effect of sealing treatment on the corrosion resistance of arc sprayed zinc coatings in atmospheric environment. The microstructures and corrosion behaviours of unsealed and sealed coatings had been studied using scanning electron microscopy and electrochemical testing. Scanning electron microscopy observations revealed that the unsealed coating consisted of an outer coarse layer and an inner impact layer. As for the sealed coating, the sealing agent not only covered the surface but also permeated into the original microdefects on the outer coarse layer of the as sprayed coating. The results of electrochemical testing and corrosion morphology observations indicated that the corrosion resistance of the sealed coating was enhanced a great extent due to the blocking and shielding effect of the sealing layer.

The optimization of microbial influenced corrosion resistance of HVOF sprayed nanostructured WC-10Co-4Cr coatings by ultrasound-assisted sealing

“…Furthermore, the pores in the outer layer are obviously more than those in the inner layer, which may be attributed to the entrapped gases escaping within an extremely short time before the final process of rapid solidification [34] . In accordance with the findings of Li et al [35] , a difference in porosity and microcracks between the inner layer and the outer layer has been found to occur in the cross-section of arc sprayed zinc coating. As shown in Fig.…”

Microstructural and Corrosion Behavior of High Velocity Arc Sprayed FeCrAl/Al Composite Coating on Q235 Steel Substrate

“…The coating exhibited low corrosion resistance because of its structural imperfection that was exposed to the electrolyte. The pores and cracks in the coating caused by high porosity act as the channels for the Cl − ions to penetrate into the coating [38,39]. The presence of defects and pores in the coating allow electrolyte diffusion, thus promoting the failure of the protective coating.…”

Wear and corrosion of CoCrFeNiMnTix high entropy alloy coatings by laser cladding

“…Hence, surface modification techniques can effectively overcome these problems and prolong its life span in a cavitation/corrosion environment. A lot of studies have been done to improve the wear and corrosion resistance of 304SS using surface modification techniques, such as magnetron sputtering technology [1], laser surface modification technique [2], plasma spraying [3] and arc-spraying [4] etc. Wang et al [5] synthesised amorphous or nanocrystalline CrNbTiMoZr high entropy alloy films on silicon wafers and 304 stainless steel by DC magnetron sputtering.…”