Structure and properties of reactively-sputtered AlxCoCrCuFeNi oxide films

Hex-element AlxCoCrCuFeNi (x = 0.5, 1, 2) metallic and oxide films were deposited by sputtering homogeneous alloy targets in argon and argon–oxygen plasma, respectively. The metallic films are primarily composed of simple face-centered and/or body-centered cubic phases, while the oxide films comprise only a cubic-spinel crystalline phase. The aluminum content plays an important role in the structure and properties of both the metallic and the oxide AlxCoCrCuFeNi films. The lattice constant increases for both the face-centered and the body-centered cubic metallic phases while it decreases linearly for the spinel phase with increasing x value. The oxide films are nanocomposite in nature and their film hardness is enhanced by both aluminum and oxygen content with the highest hardness of 22.6 ± 1.6 GPa being achieved in this series of films.