INFLUENCE OF SUBSTRATE TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF CoCrFeNiNbx HIGH ENTROPY ALLOY COATINGS

This work studies the effect of the substrate temperature on the microstructure and properties of CoCrFeNiNbx high entropy alloy (HEA) coatings fabricated by magnetron sputtering. The results indicate that all three CoCrFeNiNbx HEA coatings were composed of a simple FCC solid solution with a columnar structure. As the substrate temperature increased, Nb content in the FCC matrix increased while the grain size first decreased and then increased. Accordingly, CoCrFeNiNbx HEA coatings exhibited an increasing micro-hardness and a decreasing fracture toughness with the increasing substrate temperature. Moreover, CoCrFeNiNbx HEA coating deposited at 200(degrees) had better corrosion performance, which was due to its better surface quality and denser columnar structure compared to the other two coatings.