类金刚石碳基（DLC）薄膜具有优良的自润滑性能，其作为一种宏观固体超滑涂层具有广泛的应用前景。然而，真空环境、极端载荷及异质界面配副等苛刻工况条件下DLC薄膜寿命会显著下降，潮湿氛围、极端高温和低温对DLC薄膜自润滑行为存在着不利影响。上述不足限制了DLC薄膜在航天领域等极端工况下的应用，而通过薄膜的结构调控以匹配极端工况下超滑界面所需自润滑结构的建立条件是解决上述问题的关键。为此，论文进行了以下研究工作： 首先，基于甲苯的离子束沉积工艺，以不同的沉积偏压制备了不同结构的高含氢、高sp2杂化比例DLC薄膜；探究了沉积离子能量对薄膜元素成分、成键结构及纳米力学性能的影响机理；结合亚表层注入理论，揭示了离子能量诱导的生长模式演化对薄膜纳米结构及力学性能调控的关键作用。其次，探究了薄膜成键结构对其真空摩擦特性的影响规律，发现了高含氢、类石墨化转移膜对其自润滑的关键作用；揭示了薄膜元素成分、成键结构及力学性能对超滑转移膜建立及结构演化的影响规律；提出了碳离子亚表层注入阈值能量诱导的最优超滑性能薄膜结构；实现了薄膜10-8 mm3N-1m-1量级超低磨损率的真空、重载超滑。然后，探究了极端接触应力对薄膜自润滑性能的影响规律，揭示了接触应力诱导的界面成键结构及剪切应力演化行为；提出了类聚合物结构、高含氢类石墨结构、金属亚微米颗粒及碳化物纳米晶对薄膜超滑的影响机理；实现了薄膜4.9 GPa极端接触应力、轴承钢配副工况下的真空超滑。最后，探究了不同环境氛围、高温及超低温等复杂工况下薄膜的自润滑性能；综合验证了其在10-5~104 Pa空气压力范围、30~573 K宽温域范围内的超滑或准超滑性能的鲁棒性。综上所述，本论文从离子能量诱导的薄膜结构演化和转移膜结构演化角度建立了沉积工艺与超滑的关系；揭示了薄膜内在特性与外部极端工况对其超滑的影响机理；实现了薄膜真空磨损率2~3数量级的降低以及目前报道的最高碳基薄膜超滑接触应力，并验证了其在宽泛氛围、宽温域工况下的自润滑能力，为航天领域先进自润滑碳基薄膜的设计提供了新的思路。
Diamond-like carbon (DLC) films have excellent self-lubricating properties and have a wide application prospect as a macroscopic solid superlubricious coating. However, the lifetime of DLC films decreases significantly under harsh working conditions such as vacuum environment, extreme loads, and heterogeneous interface mating. Moreover, humid atmosphere, extreme high and low temperatures can also hamper the self-lubricating ability of DLC films. These deficiencies limit the application of DLC films under extreme conditions in the aerospace field. How to adjust the film structure to match the required self-lubricating structural evolution of the sliding interfaces under extreme operating conditions is the key to solve these problems. To this end, the following studies are conducted in this paper:Firstly, based on the ion beam deposition method of toluene ions, highly hydrogenated, sp2-rich DLC films with varied structures were prepared by adjusting the deposition bias voltage. The influencing mechanisms of deposition ion energy on the elemental composition, bonding structure and nano-mechanical properties of the films was investigated. The ion energy-induced growth mode evolution governed the nanostructure and mechanical properties of the films and the sub-implantation effect played a key role in deciding the film structure.Secondly, the influence of the bonding structure of the films on their vacuum tribological properties was investigated, and the key role of hydrogen-rich, graphite-like transfer film on self-lubrication behavior was uncovered. The comprehensive influence of film elemental composition, bonding structure and mechanical properties on the establishment of superlubricious transfer film was revealed. Sub-implantation threshold energy-induced optimized superlubricious film structure was found, and stable superlubricity under vacuum, high load was achieved with ultra-low wear rate at the magnitude of 10-8 mm3N-1m-1.Then, the influence of extreme contact pressure on the self-lubrication performance was investigated, and a four-stage model of contact pressure-induced interface structure and shear stress evolution was established to describe the role of polymer-like structure, high hydrogen-containing graphite-like structure, metal submicron particles and carbide nanocrystals on transfer films. Ultra-high Hertz contact pressure of 4.72 GPa was achieved under vacuum, bearing steel matting condition.Finally, the self-lubricating performance of DLC was investigated under different gaseous atmospheres, high and ultra-low temperatures. The results indicated that superlubricity or quasi-superlubricity can also be achieved under the air pressure range of 10-5~104 Pa, wide temperature range of 30 K~573 K.In summary, this study establishes the link between deposition parameters and superlubricity from the perspective of ion energy-induced internal structure evolution of films and their structure evolution towards transfer film. The influencing mechanisms of the intrinsic film properties and external extreme conditions on superlubricity was revealed. Based on this, 2~3 order of magnitude reduction in vacuum wear rate was realized and the highest contact pressure for superlubricity ever reported was achieved. The robust of self-lubricating ability was verified under a wide range of atmospheres, temperatures and current carrying conditions. These findings can provide new knowledge for the design of advanced carbon-based self-lubricating films for space applications.
