原位石墨烯复合铬基纳米结构涂层的构筑及减摩抗磨机理

Many fields of civil and defense industry need solid lubricant coating with good wear resistance and low friction coefficient. The traditional electrodeposited chromium coating has inadequate high temperature resistance, and its preparation process results in serious environmental pollution. A novel means for producing a new chromium base lubrication coating with good lubrication performance and perfect wear and high temperature resistance, i.e., combining the environmentally acceptable electrodeposition process based on trivalent chromium electrolyte and the in-situ composite technology of graphene prepared by electrochemical reduction, was proposed in this research. This method makes chromium base material as skeleton of the coating, and graphene as lubrication phase. Via electrochemical deposition/reduction method the second phase, i.e., graphene, was in-situ embedded in chromium coating just at the time of its formation by electrochemical reduction. Thus, a graphene/chromium base nano-structure composite coating with good lubrucation performance and wear resistance was fabricated. In this project, we will disclose the effect of preparing process conditions, electrolyte composition and etc. on the phase structure and tribological properties of the compostie coating, study its friction behavior and wear machanism, consequently laying a foundation for the development and application of the preparing technololy of the noval chromium base solid lubrication coating.

现代民用及国防工业的众多领域需要抗磨性好、摩擦系数低的固体润滑涂层。本项目针对传统电沉积铬涂层抗高温软化性能差、制备工艺严重环境污染等缺点，提出采用基于三价铬电解液的环保型电沉积方法和电化学还原石墨烯原位复合技术相结合的途径制备兼具减摩与抗磨性能、耐高温性良好的的新型铬基润滑涂层。该方法将铬基材料作为功能涂层的支撑骨架，将石墨烯作为润滑减摩相，通过电化学沉积/还原技术，使石墨烯第二相在电化学还原形成之时于原位镶嵌于铬基材料中，制备出具有铬基石墨烯复合纳米结构的抗磨减摩功能涂层。通过本项目的研究，认识和揭示制备工艺条件、电解液组成等因素对涂层微观物相结构和力学及摩擦学性能的影响，探究涂层的摩擦磨损行为和减摩抗磨机制，为新型铬基固体润滑涂层制备技术的发展和应用奠定基础。

本课题主要考察了原位石墨烯复合铬基纳米结构涂层的制备、结构和抗磨减摩行为及机制，着重研究了摩擦速度及磨损时间对该类复合涂层摩擦学性能与行为的影响，并同传统的硬铬涂层作了对比考察。研究表明，通过合理控制工艺条件，可制备出镶嵌有石墨烯纳米晶的原位复合石墨烯铬基纳米结构涂层；该类涂层的抗磨性与常规硬铬涂层在所考察的摩擦试验条件下不存在数量级的差异；在较低摩擦速度下，经热处理的复合涂层与常规硬铬涂层抗磨性相当，甚至略强，在较高速率下，其抗磨性则不及硬铬涂层；适度的低温热处理可显著改善涂层的性能；铬基涂层存在非常有趣的零磨损行为特性。然而我们也发现，在该类复合涂层与钢基底间存在界面层碳膜，如果能够将界面结合改为金属键合，复合涂层的机械性能将会大幅提高，本研究为该类涂层的研究和发展指明了方向。