Effect of Al content on wear and corrosion resistance of Ni-based alloy coatings by laser cladding

Inconel 625 + x Al (x = 0, 2.5, 5.0, 7.5, 10.0) alloy coatings were prepared by laser cladding. The addition of Al promoted the formation of the BCC phase, which changed the coating microstructure from an FCC + delta phase + Laves phase to FCC + BCC + delta phase + Laves phase. Inconel 625 + 2.5 Al alloy showed the greatest corrosion resistance among all samples. The formation of an Al2O3 film improved the corrosion resistance of the coating, but excess Al decreased the Cr2O3 content in the film, which decreased the corrosion resistance of the coating. Increasing the Al content aggravated the lattice distortion and improved the solid solution strengthening effect, while also increasing the amount of BCC phase, which improved the coating hardness. After adding Al, the Inconel 625 + x Al alloy coatings displayed strong plastic deformation resistance, and their wear resistance was improved due to the presence of a hard phase.

Automated summary

The addition of Al promotes the formation of the BCC phase, improving corrosion resistance of the coating, but excess Al can decrease the corrosion resistance. Increasing Al content can enhance coating hardness and aggravate lattice distortion.