超润滑碳基薄膜摩擦界面处剪切、重杂化及吸附钝化机制研究

Carbon-based films have attracted substantial scientific and technological attention in recent years because they has unique physical, mechanical, and tribological properties which make it an outstanding as a solid lubricant for a variety of industrial applicationsn from micro electro mechanical system (MEMS) to macro machines mechanical components. Due to the structural diversity, test conditions and environmental sensitivity of friction and wear behavior of the carbon-based films, it restrict the people to understanding of the tribological mechanism, so greatly limits its application. Base on theoretical analysis and our previous research results, the research project, from the point of view of micro/nano scale third body of carbon-based film between the sliding contact interface. Focus on the interfacial processes occurring throughout sliding such as plowing, interface shearing, rehybridization，the formation and structure of antifriction tribolayer, summarize the general and individual factors that influence the tribological behavior of the carbon-based films. Reveal the relationship between the physical and chemical characteristics of antifriction tribolayer and ultralow friction. Especially the typical physical and chemical structure of the low-shear non-stoichiometric hydrocarbon antifriction tribolayer and chemical interaction with the environment atmosphere (adsorption, passivation, desorption, etc.) of the superlow frictional carbon-base films under the self-mated sliding. Put forward the schemes to construction of superlow frictional surface, significantly reduce the friction coefficient and the way to realize superlow friction. It provides an important theoretical support for practical application of super lubricating carbon-based thin film.

碳基薄膜具有独特的物理、机械及摩擦学性能，是从微观尺度的微机电系统到宏观尺度的机械部件都具有广泛应用的固体润滑材料，在学术界和工业界均引起了极大的关注。由于碳基薄膜结构的多样性及摩擦磨损行为对测试条件和环境气氛的敏感性制约了对其摩擦机理的认识，极大的限制了其实际应用。本项目在理论分析和前期研究成果的基础上，从碳基薄膜的摩擦接触面间微纳尺度三体磨损的角度出发，关注不同摩擦条件下滑动界面处犁沟、界面剪切、重杂化、减摩摩擦层的形成及结构，归纳出影响薄膜摩擦学行为的共性和个性因素，揭示碳基薄膜减摩摩擦层的物理化学特质与超低摩擦之间的关系。特别是自配滑动下超润滑碳基薄膜滑动界面处低剪切非化学计量比碳氢减摩摩擦层的物理化学结构及与环境气氛之间的化学互作用（吸附、钝化和解吸等），提出显著减小摩擦以及构筑超润滑碳基薄膜的途径和实现超润滑的方案，为超润滑碳基薄膜的应用提供重要的理论支持。

DLC薄膜摩擦学性能对环境的敏感性极大的制约其发展和应用。因此，系统、深入地探讨多气氛下DLC薄膜表界面引起的物化特性变化，对设计、制备具有高可靠性和低环境敏感性DLC固体润滑薄膜具有重要意义。（1）采用脉冲等离子辉光放电合成了新型无定形碳纳米胶囊。在没有外部加热的中等电子束辐射下，实现了高能碳团簇自发转变成金刚石纳米颗粒，而周围类富勒烯碳基质保持几乎不变。该发现为在低温度下实现碳同素异形体之间的相变提供了一个很有前景的方法。（2）采用高频脉冲等离子体增强化学气相沉积，通过调节沉积参数，对含氢DLC薄膜微结构进行有效调控。结果表明，当沉积偏压逐渐增大时，薄膜微观结构发生“非晶-类富勒烯-非晶”的演变。（3）基于负偏压对薄膜结构的影响，在含氢DLC薄膜中主动设计类富勒烯（FL）微结构，获得了在高真空具有长磨损寿命的类富勒烯碳氢（FL-C:H）薄膜。通过考察薄膜稳态摩擦过程中的界面结构，建立了FL-C:H薄膜界面石墨化相变与磨损寿命之间的联系。与非晶碳氢薄膜相比，FL结构在剪切应力下破裂，为纳米石墨晶提供成核中心，形成纳米石墨晶/非晶结构摩擦膜。（4）考察了无/含氢DLC薄膜在不同相对湿度下的摩擦行为，探讨了吸附水分子对无/含氢DLC摩擦行为的影响机制。低湿度下，摩擦系数的主导因素为固-固接触，无氢DLC需克服较大的界面结合能，摩擦系数较高（0.19）；含氢DLC对应较小的界面结合能，摩擦系数较低（0.06）。高湿度下，无/含氢DLC表面所吸附水分子之间的氢键是影响摩擦系数的主导因素，无/含薄膜需克服的界面结合能均为约-47.31kJ/mol，两者摩擦系数十分接近（~0.15）。（5）研究了不同气氛下吸附分子对含氢DLC薄膜摩擦行为的影响规律。当分子吸附在摩擦界面形成较低的界面结合能时，摩擦系数较低；相反，则摩擦系数较高。通过含氢DLC薄膜自配副在干燥氮气下的超滑结果（摩擦系数0.009）进行了实验验证。基于此，提出了表面氢诱导氢键模型的摩擦学机制。项目执行期间在Nano Energy，Small，J. Mater. Chem. A，Adv. Mater. Interfaces，Phys. Chem. Chem. Phys.等期刊发表SCI论文19篇（其中影响因子10以上的6篇，封面论文2篇，邀请综述1篇，高倍引论文1篇），申请国家发明专利2件。已完成项目的各项内容。