Microstructure and antibacterial properties of AlCrTiZrWN high-entropy alloy nitride synthesized using HiPIMS under various N2/Ar flow ratios

Abstract

This paper reports on the use of high-power impulse magnetron sputtering (HiPIMS) to deposit (AlCrTiZrW)Nx high-entropy alloy (HEA) nitride films to a thickness of 1 μm on SKH-9 high-speed steel, SUS304 stainless-steel, and Si wafers. The primary aim was to elucidate the effects of N2/Ar flow ratio (from 10/100–150/100 sccm) on the structure of the resulting materials and antibacterial properties. Co-sputtering was performed using multiple simultaneous targets to overcome the difficulties in manufacturing HEA targets at industrial scales. XRD analysis revealed a FCC structure with (111) orientation under nitrogen gas flow of 70 sccm. Increasing the nitrogen flow to 90 sccm shifted the preferred orientation to the (200) direction. The highest water contact angle (113°) and highest hardness value (27.6 GPa) were achieved under a nitrogen flow of 70 sccm, while the best Rp value (22.7 × 105 Ω‧cm2) was achieved under 110 sccm. The antibacterial performance of the coated samples exceeded that of uncoated SUS304 stainless-steel. Overall, the incorporation of nitrogen had positive effects on HEA film properties.