Effects of RF magnetron sputtering power on the structure and nanohardness of high-entropy alloys (TiVCrNbSiTaBY)N hard coatings

High-entropy alloys (TiVCrNbSiTaBY)N hard coatings were deposited on silicon wafers and stainless steel plates using radio-frequency (RF) magnetron sputtering. The effects of RF power on the elemental composition , morphology, structure and nanohardness of coatings are evaluated. The coatings exhibit smooth surface with low roughness less than 1 nm. Higher RF power introduces more silicon into coatings and densifies the columnar structure . The coatings present nanocomposite structure of face-centered cubic phase and amorphous Si 3 N 4 . With increasing RF power, the content of amorphous phase rises and crystal grains are refined. The changes in structure lead to a tendency for nanohardness and elastic modulus of coatings to first increase and then decrease. The coating grown at 800 W has the highest nanohardness and highest elastic modulus of ∼38.1 GPa and ∼451.2 GPa, respectively. The strengthening mechanism is explained by the nanocrystal-TiN/amorphous-Si 3 N 4 model. The annealing treatment in air demonstrates that the coating exhibits excellent oxidation resistance at 800 °C.