Friction-induced rapid restructuring of graphene nanocrystallite cap layer at sliding surfaces: Short run-in period
Friction-induced rapid restructuring of graphene nanocrystallite cap layer at sliding surfaces: Short run-in period
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摩擦引起的滑动表面石墨烯纳米微晶盖层的快速重组：磨合期短
DOI：
10.1016/j.carbon.2018.01.022
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发表时间：
2018
期刊：
影响因子：
10.9
通讯作者：
Diao Dongfeng
中科院分区：
文献类型：
--
作者：
Chen Cheng;Xue Peidong;Fan Xue;Wang Chao;Diao Dongfeng
非晶碳膜作为接触滑动表面的低摩擦保护涂层有着广泛的应用。然而在达到稳定的低摩擦状态之前，膜总是经历一个被称为“磨合”期的高摩擦期，有时需要数千次滑动循环，导致显著的能量耗散。在这里，我们报告了通过制造5-nm石墨烯纳米微晶覆盖层，非晶碳膜的磨合期可以大大缩短到22 ± 5个周期。盖层引起石墨烯纳米晶化转移膜的快速形成，其响应于短的磨合期。我们发现两个关键因素的快速形成转移膜。首先，帽层的耐磨性低于非晶碳，充当快速磨损的牺牲层。第二，转移膜的纳米化主要是由于摩擦诱导的石墨烯纳米微晶的重组，而不是摩擦诱导热。此外，覆盖有多层石墨烯微片的非晶碳膜的摩擦测试也证实了摩擦诱导的石墨烯片在滑动表面处的快速重构导致了短的磨合期。
Amorphous carbon film is vastly applied for low-friction protective coatings at contact sliding surfaces. However before reaching steady low friction status, the film always endures a high friction period known as the “run-in” period, sometimes taking thousands of sliding cycles, causing remarkable energy dissipation. Here, we report that the run-in period of amorphous carbon film could be drastically shortened to 22 ± 5 cycles by fabricating a 5-nm graphene nanocrystallite cap layer. The cap layer gave rise to rapid formation of graphene nanocrystallized transfer film, which responds to the short run-in period. We found two key factors for the rapid formation of transfer film. Firstly, the cap layer had lower wear resistance than the amorphous carbon, severing as a quick-wearing sacrificial layer. Secondly, the nanocrystallization of transfer film was mainly due to friction-induced restructuring of graphene nanocrystallite but not friction-induced heat. In addition, the friction test of amorphous carbon film covered with multilayer graphene micro-flakes also verified that friction-induced rapid restructuring of graphene sheets at sliding surfaces resulted in short run-in period.