Effects of laser remelting on surface-interface morphologies, bonding modes and corrosion performances of arc-sprayed Al coating

Abstract

Purpose The purpose of this paper is to provide an experimental basis for studying the effects of laser remelting on the surface modification of arc-sprayed Al coating. Design/methodology/approach A layer of arc-sprayed Al coating on S355 steel was remelted with a CO2 laser, and the surface-interface morphologies, compositions of chemical elements and phases of Al coating were analyzed with scanning electron microscopy, energy disperse spectroscopy and X-ray diffraction, respectively. The effects of laser remelting on compositions of chemical elements and bonding performance of Al coatings were discussed. Findings The result shows that there are some pores existing on the Al coating surface after arc spraying, and the combination mode of coating interface is primarily composed of mechanical bonding. The pores on the Al coating reduce after laser remelting, which improves the compact performance, and the mechanical binding mode by arc spraying is changed into metallurgical bonding. The Fe and Al atoms at the coating interface are distributed with gradient, and the stratified enrichment is evident, which improves binding performance of the Al coating. The Al coating exhibits general corrosion before laser remelting and local corrosion after laser remelting, which improves the corrosion resistance of Al coating. Originality/value The arc-sprayed Al coating is remelted by CO2 laser, improving its microstructures and bonding mode with the substrate.

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“…The reduced porosity level of an arc-sprayed aluminium coating was also achieved by Wenming et al, who used a CO laser to re-melt the coating [61]. They also noticed that the re-melting of the coating changed the way the coating adhered to the substrate from mechanical to metallurgical bonding.…”

Application of zirconia thermal barrier coating on the surface of pulling-straightening roller

“…Munez et al verified that laser remelting can improve the quality of thermal spraying coating by reducing the coating porosity [5]. Liu et al revealed that, through laster remelting, the bonding of coating-substrate interface shifted from mechanical bonding to metallurgical bonding, and the coating had a stronger corrosion resistance [6]. Probing into the damage mechanism of TBCs after laser remelting, Fan et al concluded that the coating damages are related to the surface morphology and segmented cracks [7].…”

Characterization of Short Time Marine Corroded Surfaces

“…Corrosion studies usually focus on industrial standards of salt spraying tests and cyclic accelerated corrosion tests, 9 the load-bearing mechanical properties and the speed of corrosion. There are reports on the corrosion of sacrificial coatings, [10][11][12] and the "corrosion resistance" of the S355 steel through the rust surface coverage and electronic impedance of the steel rather than the surface chemical speciations. 13 Importantly the simulation tests are conducted over relatively long time periods (days, years, if not decades).…”