Cold spray coating of AlCrCoFeNi high entropy alloy for corrosion protection of powder metal parts

Cold spray coating, also known as supersonic particle disposition, is a process that is applicable to corrosion resistance, dimensional restoration and wear resistance coatings. The unique ability to provide a corrosive resistant coating with convenience and environmental friendliness is the main attraction to cold spray coatings. In this study, a high entropy alloy with an equimolar composition of AlCoCrFeNi was cold sprayed on F-0008 powder metal part for surface modification and corrosion protection. The cold spray coating was performed at 600 °C in the air as well as in nitrogen atmosphere. To improve the surface coating, cold sprayed specimens were heat treated at 900 °C in argon atmosphere for 2 hrs. Corrosion testing was performed on assintered, cold-sprayed, and heat-treated specimens by exposing the specimens with salt-spray until corrosion state reaches ~ 50%, determined visually. Detailed characterization of the coating thickness, elemental analysis, and corrosion behavior of the specimens are reported in this paper.