Effect of bias voltages on microstructure and mechanical properties of (AlCrNbSiTi)N high entropy alloy nitride coatings deposited by arc ion plating

Abstract

(AlCrNbSiTi)N coatings were prepared by arc ion plating at a bias voltage in the range of −50 to −200 V. The as-deposited coatings were all found to have a face-centred cubic structure and exhibit columnar crystal. Si₃N₄ is distributed in the columnar grains in the form of a network, which separates the columnar grains into fine grains. Si₃N₄ presents a crystalline state and grows coherently with the surrounding grains to form a nc-(AlCrNbTi)N/nc-Si₃N₄ nanocomposite structure. The coating with the finest mechanical characteristics was applied at −200 V. The hardness, elastic modulus and wear rate are 34.76, 425 GPa and 0.82 × 10⁻⁹ mm³ N⁻¹  m⁻¹, respectively. Based on the outstanding mechanical performance of the coating, it is concluded that the (AlCrNbSiTi)N protective coating has a broad range of potential applications.