FeCrAl coatings usually possess high wear and corrosion resistance and can be applied to steel substrates to improve their surface properties. Al on the other hand has good corrosion properties and high strength to weight ratio. Arc spraying provides a possibility of using two dissimilar wires to form a pseudo-alloy coating that possesses combined individual properties. In this study, the FeCrAl and Al wires were sprayed simultaneously as the anode and cathode, respectively to obtain FeCrAl/Al composite coating deposited on Q235 steel substrate. The microstructure and wear properties of the as-sprayed coatings were studied and compared with the annealed coatings.

It was found that the as-sprayed coating had a dense lamellar structure with alternating FeCrAl and Al splats. The microhardness of the as-sprayed coating comprised of hard FeCr splats and ductile Al splats. The as-sprayed coating had a porosity of 4.7% and microhardness of 494 HV_0.1. Compared with the as-sprayed coating, the annealed coatings had a lower porosity and the highest adhesion strength obtained was approximately 29.96 MPa, for the coating annealed at a temperature of 300 ℃. This was attributed to the densification and sintering process that improved the compaction of the coating structure. At temperature of 500 ℃, the FeAl intermetallic compounds formed at the splat interfaces. The annealing temperature influenced the microstructure of the composite coating while the microhardness became more uniform and slightly increased with temperature but decreased with further increase in temperature at 700 ℃. Wear resistance of the as-sprayed and annealed coatings was significantly higher than that of the substrate. The dominant wear mechanism of the coatings was splat delamination and plastic deformation.