具有纳米核壳结构的碳基薄膜在固油复合体系中的自催化特性及摩擦学行为

The friction and wear of key components of domestic automobile engine lead to excessive energy consumption. This proposal report is about the investigation on a kind of novel carbon-based nanocomposite protective film that suitable for the key components. The special core-shell structure that composed of the encapsulated transition metal nanoparticles and onion-like carbon nanoshells can endow the carbon film with high hardness, high toughness, and excellent autocatalytic and self-lubricating properties. In the solid-oil compound system, the novel carbon film can show an outstanding tribological property, and the encapsulated transition metal nanoparticles can induce oil molecules transform into “carbon-rich tribofilm” and further reduce the system friction and wear, it will effectively avoid the unnecessary loss of carbon film and then ensure its long operating life. The so-called carbon-based nanocomposite film with core-shell structure can be deposited by magnetron sputtering equipped with the multiple doping means. As a research object, the mechanism of the influence of the element doping on the formation of special core-shell structure will be investigated. The relationship between the microstructure, mechanical properties, catalytic activity and tribological properties of carbon film will be established. The coupling mechanism between the film autocatalytic and self-lubricating properties in the solid-oil composite system will be also revealed. The goal of the proposal is to obtain the carbon-based nanocomposite film with superb mechanical properties, catalytic activity and tribological properties to protect the key components of domestic automobile engine, and to know how to design and apply this kind of film in the future.

本项目针对我国汽车发动机关键部件因摩擦磨损导致发动机耗能过大的问题，构建一种适用于关键部件的新型碳基纳米复合保护薄膜：由类洋葱纳米碳壳包裹过渡金属纳米粒子的特殊核壳结构可赋予薄膜高硬高韧以及优异的自催化自润滑特性。在固油复合体系中新型碳膜可充分发挥自身的低摩擦低磨损特性，同时包裹态过渡金属纳米粒子可诱导油分子向“富碳转移膜”转变，进一步减小体系摩擦磨损，有效避免碳膜的不必要损耗从而保障其长久运行寿命。本研究利用多元共掺杂与磁控溅射相结合，实现具有核壳结构的碳基纳米复合薄膜的可控制备；并探究薄膜生长过程中多元掺杂对特殊核壳结构形成的作用机制；建立碳基纳米复合薄膜中微观结构与力学、催化活性及摩擦学性能的关系；揭示固油复合体系中碳膜自催化性能与自润滑性能的耦合机制；最终为我国汽车发动机关键部件保护涂层的设计提供科学依据。

当前解决机械部件摩擦磨损问题最常见方案是油基润滑剂，但单一的油基润滑方法显然已经不能适应当前工业技术的快速发展。基于碳基、氮基及硼基等涂层材料发展起来的固液复合润滑体系有望在保护金属基板的同时，突破传统润滑方案的瓶颈，大大提高润滑系统的综合能力，也符合严格的环境限制。本项目发展了一系列由过渡金属和轻元素（C、N、B）组成的兼具高硬韧、低摩擦、耐磨损以及催化能力的防护涂层材料，实现了固液复合润滑体系性能的进一步提升：利用Ag掺杂并构筑固溶体结构的方式实现过渡金属氮化物涂层的机械强度和催化能力的双优化，从而在固油复合体系中发挥超低摩擦超低磨损特性；通过Ni掺杂并构筑非晶碳包裹Ni3C纳米晶的特殊核壳结构提升碳基涂层的力学性能并赋予其催化能力，Ni3C纳米晶具有优异的诱导周围“碳源”石墨化的天然优势，由此提升固油复合体系的整体摩擦学性能；以构筑类富勒烯结构和掺杂F元素的方式强化碳基涂层的力学和在固水复合体系中的摩擦学性能；通过调控微观结构中结晶相组成和比例实现过渡金属氮化物和硼化物的力学性能优化，并在固水复合体系中首次发现过渡金属硼化物涂层稳健的宏观超滑现象，通过摩后分析和模拟计算揭示了涂层超滑及超耐磨的原子级机制。以上结果发表于Advanced Science、Journal of Physical Chemistry Letters、Friction、Ceramics International和Surface & Coatings Technology等期刊上。