Deposition behaviour of FeCrMnNiCo coatings deposited using mechanically alloyed powder: Comparing Cold Spray, HVOF, HVAF, and Laser Cladding processes

This study examined the characteristics of mechanically alloyed (MA) Cantor alloy powder and the coatings produced from it using various deposition techniques, including cold spray (CS), high-velocity oxy-fuel, high-velocity air-fuel, and laser cladding (LC). Microstructure analysis of the MA powder revealed an irregular morphology and incomplete elemental mixing. The microstructure of the CS coating displayed an FCC crystal structure, with some XRD peaks corresponding to BCC phases due to the presence of unmixed elements. In contrast, all other coatings also exhibited oxides alongside FCC and BCC phases, with the LC coating containing a higher concentration of oxides. These coatings demonstrated high density and diverse microstructures, with CS coatings demonstrating effective transfer of powder microstructure. The CS coating had the highest hardness (679 ± 17 HV 0.1 ) due to the retention of deformed microstructure from the powder, whilst the LC coating had the lowest hardness (215 ± 10 HV 0.1 ). CALPHAD calculations using Thermo-Calc suggest that the presence of oxides in the coatings could be thermodynamically feasible, depending on the conditions. Deposition efficiency varied significantly among the methods, with LC achieving the highest efficiency (63 ± 6 %) and CS the lowest (14 ± 1 %). • MA powder displayed irregular morphology and incomplete elemental mixing • CS coating had an FCC structure with some BCC phases from unmixed elements • LC coating showed more oxides and had the lowest hardness among coatings • CS coating retained deformed microstructure, resulting in highest hardness • LC achieved the highest deposition efficiency, whilst CS had the lowest