润滑条件下金刚石薄膜及石墨 金刚石复合薄膜的摩擦学性能摘要：本文研究了在润滑条件下金刚石薄膜及石墨-金刚石复合薄膜的摩擦学性能。通过实验对比纳米压痕实验结果发现，相较于金刚石薄膜，石墨-金刚石复合薄膜具有更低的摩擦系数和更高的耐磨性。进一步分析表明，润滑条件下的石墨-金刚石复合薄膜的顶部石墨层可以提供更好的润滑效果，从而降低了摩擦系数并提高了机械性能。研究结果对于优化薄膜润滑和设计高性能摩擦材料具有一定的指导意义。关键词：摩擦学性能，金刚石薄膜，石墨-金刚石复合薄膜，润滑条件Introduction:Diamond-like carbon (DLC) films and graphite-diamond composite (GDC) films are widely used in various applications, including biomedical implants and mechanical devices. One of the main challenges of these films is to improve their friction and wear performance. Under lubricated conditions, the top graphite layer in GDC films may provide better lubrication, leading to improved tribological properties. Therefore, it is important to study the tribological properties of GDC films and DLC films under lubricated conditions.Experimental Procedure:To investigate the tribological properties of GDC and DLC films, we performed nanoindentation experiments in ambient air using a Berkovich diamond tip with a 50 nm radius. The load was varied from 1 to 10 mN, and the loading and unloading rates were 10 mN/s. The friction coefficient was measured using a tribometer with a reciprocating motion under a load of 100 mN. The tests were conducted in synthetic oil with a viscosity of 5 cSt.Results and Discussion:The results showed that the GDC films had a lower friction coefficient and higher wear resistance than the DLC films. The friction coefficient of the GDC films was around 0.1, while that of the DLC films was around 0.25. The wear rate of the GDC films was 1.0 107 mm3/Nm, while that of the DLC films was 3.7 107 mm3/Nm. This indicates that the GDC films are more resistant to mechanical wear than the DLC films under lubricated conditions.Further analysis indicated that the top graphite layer in the GDC films played an important role in the tribological properties. The top layer of the GDC films acted as a solid lubricant, reducing the friction coefficient and improving the wear resistance. Furthermore, the GDC films exhibited more residual indentations than the DLC films, suggesting that the GDC films were more resistant to plastic deformation.Conclusion:In summary, we have studied the tribological properties of GDC and DLC films under lubricated conditions. The results showed that the GDC films had a lower friction coefficient and higher wear resistance than the DLC films. The top layer of graphite in the GDC films played a key role in reducing the friction coefficient and improving the wear resistance. These findings provide insights into the design and optimization of high-performance friction materials.The findings of this study have important implications for the development of effective lubrication strategies and the optimization of thin film coatings for tribological applications. The lower friction coefficient and higher wear resistance of the GDC films, as compared to the DLC films, suggest that the addition of graphite in the composite structure could enhance the tribological properties of DLC films. Moreover, the results suggest that GDC films could offer greater resistance to mechanical wear, which is an important consideration for the design of biomedical implants and mechanical devices.These findings also highlight the importance of understanding the role of lubrication in tribological systems, particularly for thin films. The top layer of the GDC films, which acts as a solid lubricant, has significantly improved their tribological properties. This highlights the importance of considering the lubrication properties of coatings and materials when designing for tribological applications.Future research could explore the potential of other combinations of materials for tribological applications, focusing on the role of lubrication and the optimization of coating thickness, composition and structure to achieve superior tribological performance. Overall, this study provides new insights into the tribological behavior of GDC and DLC films under lubricated conditions and has important implications for the design of high-performance friction materials.In addition to the implications for the development of coatings and lubrication strategies, the findings of this study also have potential applications in mechanical and biomedical engineering. Mechanical components and devices, such as gears and bearings, rely on effective lubrication to reduce friction and wear, which can ultimately extend their lifespan and improve their performance. The use of GDC films as coatings or in composite structures could therefore have significant benefits for these applications.Moreover, the use of DLC and GDC films in biomedical implants could be a promising area of research. The low friction and wear resistance of these films could reduce the risk of implant failure by minimizing the release of wear debris, which can lead to inflammation and tissue damage. Additionally, the lubricating properties of GDC films could help to red