A comparative study of thermodynamic and high-temperature tribological properties of ZrCN coatings and Ti60 substrate using first-principles calculations and experimental methods

Abstract

To improve the mechanism and high temperature wear resistance of Ti60 substrate, ZrCN coating and Ti60 substrate were systematically studied by combining the first-principles calculation and double glow plasma surface alloying methods. The coating exhibited gradient changes in composition and structure. The hardness of the coating was determined to be approximately 17.4 GPa, about four times higher than that of the substrate. The interfacial adhesion strength of the coating reached 4.49 J/m², corresponding to its good crack propagation resistance (CPRs = 385). The coating significantly reduced wear rates at high temperatures compared to the substrate, with values of approximately 7.7 × 10⁻⁵ mm³ · N⁻¹ m⁻¹ at 500 °C, 3.3 × 10⁻⁵ mm³ · N⁻¹ m⁻¹ at 600 °C, and 7.5 × 10⁻⁵ mm³ · N⁻¹ m⁻¹ at 700 °C, respectively. These improvements were attributed to the coating's good mechanical and thermal stability, including strong bonding strength, a low thermal expansion coefficient, and low Gibbs free energy. In addition, the formation of a tribo-layer and interlayer nitrides, consisting of ZrO₂, Ti₂ZrO, (Zr, Ti)O₂, and TiN phases at high temperatures, further enhanced its superior performance.