二硫化钼(MoS₂)薄膜是一种性能优异的润滑材料, 但在高温条件下容易氧化成MoO₃, 极大降低润滑性能。为提高MoS₂薄膜的力学性能和高温摩擦学性能, 该文采用直流磁控和高功率脉冲复合溅射技术制备了掺杂非晶碳的MoS₂-C复合薄膜, 并研究了非晶碳掺杂及含量对MoS₂薄膜的微观结构、力学性能和摩擦学性能的影响。结果表明：MoS₂-C复合薄膜表现出(002)晶面的择优取向, 非晶碳的掺入使其具有致密的结构, 同时呈现较低的表面粗糙度。掺杂合适含量非晶碳的MoS₂-C复合薄膜纳米硬度和弹性模量分别达到5.50和82.53 GPa; 膜基结合力达到8.30 N, 约为纯MoS₂薄膜的3.6倍。MoS₂及MoS₂-C复合薄膜在室温下的摩擦学性能表现不佳, 这主要是由于空气水分子对摩擦界面MoS₂层间的侵入和氧化。MoS₂-C复合薄膜在真空环境下的摩擦学性能得到提升, 主要是由于隔绝了氧气的侵蚀。100~300 ℃高温条件下, MoS₂-C复合薄膜摩擦系数低于纯MoS₂薄膜。特别在300 ℃下, 纯MoS₂薄膜迅速发生失效, MoS₂-C复合薄膜仍具有较低的摩擦系数和较长的磨损寿命, 这主要是由于碳的掺入有效抑制了MoS₂在高温环境下的氧化, 从而提升了薄膜在高温环境下的耐磨性和承载能力。

Objective: Molybdenum disulfide (MoS₂) is a multifunctional material primarily used in lubrication, electronics, and catalysis. MoS₂ films are widely utilized in the aerospace industry due to their excellent lubrication properties. These films are applied in aircraft landing gear, engine components, and moving parts of spacecraft to ensure efficient operation and minimize frictional wear. However, under high-temperature conditions, MoS₂ films are susceptible to oxidation into molybdenum trioxide, significantly degrading their lubricating performance and restricting their applicability in high-temperature environments. Methods: Herein, MoS₂ films were enhanced by doping them with amorphous carbon to improve their mechanical properties and high-temperature tribological performance. Using direct-current magnetron sputtering, medium-frequency magnetron sputtering, and high-power pulsed composite sputtering techniques, MoS₂-C composite films were fabricated. The effects of doping amorphous carbon and its concentration on the microstructure, mechanical properties, and tribological performance of MoS₂ films were thoroughly investigated. Results: The results revealed that the MoS₂-C composite films exhibited a preferential orientation of the (002) crystal plane. Amorphous carbon incorporation into the MoS₂ matrix resulted in a dense and uniform structure while reducing surface roughness. This structural modification enhanced the mechanical and tribological properties of the films. Doping MoS₂-C composite films with an optimal amount of amorphous carbon significantly improved their mechanical properties. Their nanohardness and elastic modulus reached 5.50 and 82.53 GPa, respectively, while substrate adhesion strength increased to 8.30 N, approximately 3.6 times higher than that of pure MoS₂ films. These improvements suggest that amorphous carbon addition enhances the mechanical strength and durability of the films. At room temperature, both MoS₂ and MoS₂-C composite films exhibited poor tribological performance, primarily due to the infiltration of moisture molecules from air into the MoS₂ interlayers. This results in MoS₂ oxidation, compromising the lubrication properties of the films. Meanwhile, the tribological performance of MoS₂-C composite films substantially improved in a vacuum environment, attributed to the isolation from oxygen, preventing oxidation and allowing the films to maintain their lubricating properties. Under high-temperature conditions (100 ℃-300 ℃), MoS₂-C films outperformed pure MoS₂ films by maintaining a lower friction coefficient. MoS₂-C films with 37.41% atomic percentage of carbon exhibited the lowest wear rate of 9.75×10^-8 mm/(N·m) while showing a friction coefficient of 0.008 at 200 ℃, which is the lowest value among all samples. Notably, at 300 ℃, pure MoS₂ films quickly failed due to oxidation, whereas MoS₂-C composite films retained a lower friction coefficient and longer wear life. This improvement is primarily attributed to the incorporation of carbon, which effectively inhibits MoS₂ oxidation in high-temperature environments. Conclusions: MoS₂-C composite films exhibit enhanced wear resistance and load-bearing capacity at elevated temperatures. These findings suggest that doping amorphous carbon into MoS₂ films significantly improves their tribological and mechanical properties, especially under high-temperature conditions. MoS₂-C composite films demonstrate excellent wear resistance and prolonged service life, making them promising for high-temperature lubrication applications. By optimizing the carbon content, it is possible to further enhance the high-temperature lubrication performance of MoS₂ films while maintaining their excellent mechanical properties. This provides new possibilities for developing advanced tribological coatings that effectively perform under harsh operating conditions.