Wang Jia, Zhang Kan, Wang Fuguo, Zheng Weitao
State Key Laboratory of Superhard Materials, Department of Materials Science, Key Laboratory of Automobile Materials, MOE, Jilin University Changchun 130012 P. R. China
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences Lanzhou 730000 P. R. China
RSC Adv. 2018 Mar 23;8(21):11388-11394. doi: 10.1039/c8ra00580j. eCollection 2018 Mar 21.
Surface energy is essential to the friction properties of materials, but until now the investigating scope for DLC films has still been narrow. In this paper, we try to expand the surface energy scope of DLC films to their limits by surface modification and study their influence on friction properties. In this case, we not only control the surface energy of DLC films but also manipulate that of the counter balls, by using piranha etching and octadecyltrichlorosilane (OTS) modification. The surface compositions, wettabilities and friction properties of DLC films and counter balls were investigated. The results indicate that the surface energies of DLC films and counter balls can be adjusted successfully in the ranges of 31.2 to 73.73 mJ m and 15.69 to 72.93 mJ m, respectively. The frictional tests show that all the as-modified DLC films retain relatively stable friction curves, which derive from their good load-carrying and wear-resistance capabilities. Specifically, the DLC-OH covered with vast oxygen-containing groups shows poor frictional properties, owing to its high surface energy and strong adhesion. In contrast, the DLC-OTS exhibits amazing friction reduction properties, due to its ultra-low surface energy and special film structure.
表面能对材料的摩擦性能至关重要，但迄今为止，类金刚石碳（DLC）薄膜的研究范围仍然狭窄。在本文中，我们试图通过表面改性将DLC薄膜的表面能范围扩展到极限，并研究其对摩擦性能的影响。在这种情况下，我们不仅控制DLC薄膜的表面能，还通过使用硫酸-过氧化氢混合溶液蚀刻和十八烷基三氯硅烷（OTS）改性来操控配对球的表面能。研究了DLC薄膜和配对球的表面成分、润湿性和摩擦性能。结果表明，DLC薄膜和配对球的表面能分别可以成功地在31.2至73.73 mJ/m²和15.69至72.93 mJ/m²范围内进行调节。摩擦测试表明，所有改性后的DLC薄膜都保持相对稳定的摩擦曲线，这源于它们良好的承载能力和耐磨性能。具体而言，覆盖有大量含氧基团的DLC-OH由于其高表面能和强附着力而表现出较差的摩擦性能。相比之下，DLC-OTS由于其超低表面能和特殊的薄膜结构而表现出惊人的减摩性能。
