Optimizing substrate bias voltage to improve mechanical and tribological properties of ductile FeCoNiCu high entropy alloy coatings with FCC structure

• Published in: Journal of alloys and compounds 2024-11, Vol.1004, p.175972, Article 175972
• Main Authors: Jiang, X., Zeng, X.K., Xie, W., Liu, M., Leng, Y.X.
• Format: Article
• Language: English
• Subjects: Bias voltage; High entropy alloy coatings; Magnetron sputtering; Mechanical properties; Tribological properties
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.175972

Conventional hard coatings are limited in their tribological applications due to their high brittleness. High-entropy alloy (HEA) coatings, which combine high toughness and hardness, represent a new class of tribological coatings with great potential. The microstructure and stress state of HEA coatings can be significantly affected by the deposition parameters of magnetron sputtering, which can regulate their mechanical and tribological properties. In this study, DC magnetron sputtering with varying substrate bias voltages was used to deposit FeCoNiCu HEA coatings with an FCC single phase structure on 316 stainless steel. The microstructure, mechanical, and tribological properties of these coatings were studied in detail. The residual tensile stress of the coatings decreases, while toughness and hardness increase as the bias voltage increases. The coatings exhibited optimal toughness, highest hardness (11.3 GPa), and the lowest wear rate (as low as 6.01 × 10−5 mm3/N·m) when the bias voltage was set to −200 V. The formation of a metal oxide adhesion layer during friction improved the tribological properties of the coatings. This study demonstrates that optimizing the deposition bias voltage is an effective way to improve the mechanical and tribological properties of high-entropy, face-centered cubic alloy coatings, which are intrinsically tough and ductile. •The ductile FeCoNiCu high-entropy alloy coating with FCC structure was deposited.•Coatings exhibit high hardness, good toughness and self-sustaining properties.•Effect of bias voltage on structure, mechanical and tribological properties of coatings was studied.•Lowest wear rate of −200 V coatings is attributed to the combination of high hardness and good toughness.