In order to address the weaknesses of poor corrosion resistance of hydraulic cylinder piston rods, we have developed a surface protection strategy for titanium aluminum nitride coatings by filter cathode vacuum arc (FCVA) technology. The optimization and regulatory mechanism of N₂ flow rate on the microstructure, mechanical, and electrochemical oxidation behaviors have been emphasized. The results indicated that all coatings revealed a nanocrystalline amorphous composite structure dominated by an fcc TiAlN phase. However, the solid solution content, growth orientation, and grain size could be controlled by the nitrogen flow rate, thereby achieving optimized hardness, adhesion strength, corrosion, and oxidation resistance. Specifically, with the increase in the N₂ flow rate, the solid solution content continued to rise, while the crystal orientation transformed from the (111) to the (200) plane, and the grain size initially increased and then decreased. As a result, mechanical properties, including hardness, toughness, resistance to plastic deformation, and adhesion strength, displayed a trend of initially increasing and then decreasing. The corrosion failure of coatings was linked to surface defects controlled by the N₂ flow rate, rather than the composition and phase structure. The coating displayed superior corrosion resistance at low N₂ flow rates due to fewer macroscopic particles and pore defects. This study provides valuable insights into the corrosion behavior of an aluminum titanium nitrogen coating, providing crucial guidance for coating design in harsh environments.

Lubrication performance is a critical index determining the service performance of self-lubricating ceramic cutting tools, but the coupling between mechanical properties, lubrication, and wear makes the lubrication effect challenging to predict. In this paper, WC-cBN-MoS₂ self-lubricating ceramics with 15 vol% MoS₂ and a range of mechanical properties (Vickers hardness: 10.33–20.22 GPa; fracture toughness: 1.8–5.95 MPa·m^1/2) were fabricated by high-pressure sintering. A lubricating particle release model is established to analyze the contributions of matrix deformation and surface wear to lubricant release. It is found that matrix deformation alone cannot extrude lubricating particles to the surface; instead, wear is the primary mechanism supplying particles to the friction interface. The lubricating film, containing both ceramic matrix debris and lubricating particles, exhibits characteristics of multi-media powder lubrication, with film thickness increasing linearly with applied load and sliding speed. The friction coefficient shows a non-monotonic relationship with load and speed, attributed to the coexistence of powder lubrication within the film and quasi-boundary lubrication at the upper interface. A predictive model is established based on the superposition of these two mechanisms, and its predictions agree well with experimental measurements. This work clarifies the multiple lubrication mechanisms of self-lubricating ceramics and provides a quantitative framework for predicting their tribological performance.