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• AlCuNiTiZr high entropy alloy films deposited by magnetron sputtering • AlCuNiTiZr films showing excellent anti-corrosion properties • A scheme of a reasonable equivalent electrical circuit proposed In this study, corrosion-resistant AlCuNiTiZr high-entropy alloy (HEA) films were deposited by direct current magnetron sputtering. The films were found to be amorphous. Corrosion resistance of the films in 0.5 M H 2 SO 4 solution were investigated and compared with 316L stainless steel. The minimum corrosion current density of the HEA films was about one order of magnitude lower than that of 316L stainless steel. The inductively coupled plasma optical emission spectra showed that the concentrations of Cu, Ni, Ti and Zr ions in the corrosion solution were as low as 10−7 mol / L, while the concentration of Al ions was 7.5×10−6 mol / L. It is revealed that two passivation layers were formed on the surface from electrochemical impedance spectroscopy and equivalent electrical circuit, and the passivation layers resulted in protective effect on the AlCuNiTiZr HEA films in the sulfuric acid solution. [ABSTRACT FROM AUTHOR]

AlCu x NiTiZr 0.75 high entropy alloy (HEA) films were deposited by magnetron sputtering with an alloy target in combination with a pure Cu metal target. The purpose of this study was to reduce electrical resistivity of the HEA films while maintaining mechanical properties and corrosion resistance by adjusting Cu content of the HEA. We found that the AlCu x NiTiZr 0.75 HEA films were amorphous and displayed a homogeneous or columnar microstructure along the cross sections. The increase of Cu content changed the electronic structure of the HEA films, so that the resistivity decreased sharply to 66 μΩ·cm at x = 1.4. The hardness-to-elastic modulus ration H/E, an indicator of a material's ductility, attained the maximum value at x = 1.4. Although the corrosion current densities increased with x , they were all below 10−6 A/cm2 in 3.5 wt% NaCl solution, indicating good corrosion resistance. These findings assumably help expand industrial application of HEA films, particularly when conductivity is required for the functionality of the films. • Amorphous AlCuxNiTiZr 0.75 high entropy alloy films were deposited by co-sputtering. • AlCuxNiTiZr 0.75 films maintained high hardness and good corrosion resistance. • The electronic structure of AlCuxNiTiZr 0.75 films were changed, and the lowest resistivity was 66 μΩ·cm. [ABSTRACT FROM AUTHOR]