Microstructure and mechanical properties of FeCoCrNiAl0.1N high entropy alloy nitride coatings synthesized by cathodic arc ion plating using alloy target

Abstract

To promote the industrial application of high entropy alloy nitride (HEAN) coatings, the cathodic arc ion plating deposition process was explored to deposit FeCoCrNiAl0.1 N using casting HEA alloy targets. We investigated the impacts of nitrogen pressure and bias voltage on the microstructure, mechanical characteristics, and friction behaviors. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to analyze the microstructures. It was found that compositions for all coatings were uniformly and the coatings mainly consisted of FCC-HEA, CrN, AlN, and FeN phases. The nano hardness and plastic deformation resistance, characterized by nano-indentation, both increased with the nitrogen pressure and certain bias voltage (<150 V). Coating deposited with 2.0 Pa and 150 V presented the maximum hardness of 32.9 GPa and the highest H3/E2 value of 0.1 GPa. The hardening mechanism was focused. Coatings deposited with low nitrogen pressure presented better crack resistance under scratch load. The friction behaviors were presented based on the combined studies of friction curves, wear track profiles, and morphologies. FeCoCrNiAl0.1 N coatings revealed excellent wear resistance with relatively lower COF (ranging from 0.43 to 0.51).