CrN/CrSiN multilayer coatings with different Si contents (Si-5, Si-10, Si-15) were fabricated by arc ion plating. The microstructure, mechanical properties, electrochemical performance and tribocorrosion behavior of the coatings were investigated systematically. The coatings were mainly composed of CrN phase. With increasing Si content, grain refinement and diffraction peak broadening of CrN were observed, while no significant changes in coating hardness or adhesion strength were detected. Electrochemical measurements revealed that the densification of the coatings was improved by Si doping, which consequently led to an increase in pore resistance (R_f) with higher Si content, while the charge transfer resistance (R_ct) was reduced. The Si-15 coating exhibited the lowest R_ct value of 1.08 × 10⁴ Ω·cm². Compared with the CrN coating, the tribocorrosion resistance was improved through the adoption of the Si doping multilayer structure. However, the performance was not linearly enhanced with increasing Si content. The Si-15 coating presented the highest tribocorrosion rate of 1.81 × 10^–6 mm³/(N·m) among the CrN/CrSiN multilayer coatings. It was found that excessive Si content enlarged the potential difference between the coating and substrate, which exacerbated galvanic corrosion at the interface and consequently degraded the tribocorrosion performance. Finally, the tribocorrosion failure mechanism of the CrN/CrSiN coatings was discussed.

The effects of RF plasma treatments using different gases (Ar, O₂, and N₂) and processing parameters on the surface wettability of polyethylene terephthalate (PET) films were systematically investigated. Atomic force microscopy (AFM) and X–ray photoelectron spectroscopy (XPS) were employed to characterize the evolution of surface topography and chemical composition. While all treatments enhanced hydrophilicity, the magnitude of improvement and the governing mechanisms were gas-dependent. Among them, O₂ plasma treatment exhibited the most pronounced effect: under optimal conditions (20 W, 80 s), the water contact angle (WCA) was reduced to 3.7°, indicating a superhydrophilic surface. This enhancement was primarily attributed to a substantial increase in surface oxygen content (O/C ratio) and the incorporation of strongly polar oxygen-containing functional groups, such as C=O and COOH. N₂ plasma offered moderate improvement via nitrogen-containing groups, while non-reactive Ar plasma relied primarily on physical etching, yielding the smallest enhancement. Analysis revealed that wettability evolution was dominated by increased polar surface energy from chemical functionalization, with surface roughness playing a synergistic role. These results demonstrate that optimizing plasma gas and parameters effectively controls PET wettability through the coupled regulation of surface chemistry and topography.