Structural Modulation and Tribological Behavior of Cr-Based Coatings Deposited by Arc Ion Plating

Severe surface wear serves as a critical factor that limits the service life and operational reliability of precision mechanical components, whereas protective coatings offer an effective approach to mitigate surface wear and prolong the service life of mechanical parts. Although multiple studies focus on Cr-based coatings, the systematic correlation between coating microstructure and tribological properties remains unclear. Herein, Cr, CrN, CrN/Cr multilayer, and gradient CrN coatings are deposited on CrNi3MoVA steel by arc ion plating, and their tribological behaviors are systematically evaluated through sliding tests, three-dimensional wear-track profilometry, and SEM/EDS characterization. The results reveal a pronounced dependence of wear resistance on coating architecture, with the gradient CrN coating exhibiting the most stable and uniform wear behavior with the lowest material loss during sliding service. The superior wear resistance stems from the gradual compositional and microstructural transition from metallic Cr to ceramic CrN, which achieves uniform stress transfer, alleviates stress concentration, and suppresses crack initiation and damage propagation. The wear mechanism of the gradient CrN coating is dominated by mild adhesive wear, accompanied by slight tribo-oxidation, interfacial material transfer and minor third-body abrasive wear. This study demonstrates that gradient structure design provides an effective strategy for improving the structural stability and tribological durability of Cr-based coatings and offers a promising approach for surface wear protection and service life extension of precision mechanical components.