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

Abstract

PurposeThe 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/approachA 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.FindingsThe 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/valueThe arc-sprayed Al coating is remelted by CO2 laser, improving its microstructures and bonding mode with the substrate.