机械密封环端面梯度金刚石薄膜的沉积及耐磨减摩机理研究

In order to solve the problem of rapidly wear and low reliability of mechanical seal end faces in harsh media and working conditions, this project is focused on the deposition and tribological behavior of graded diamond films on mechanical seal end faces, in purpose of upgrading the property of end faces. This project contains four parts: firstly, the setup of closed-loop control system on deposition parameters, combined with the physical field simulation techniques based on the coupled thermo-hydro-mechanical model are used to deposit uniform diamond films on mechanical seals in large-scaled area. Secondly, the graded MCD/FGD/NCD/UNCD film is introduced to break through the performance limits of single-layered diamond film, combined with the control technology of residual inner stresses in diamond film, the smooth diamond films with excellent wear resistance and bonding strength is obtained on mechanical seals. Thirdly, the tribotests are adopted to study the tribo-film forming ability, wear mode and chemical reaction of diamond films in strong abrasive wear, acidic, alkaline and warm water media under varied working conditions, and obtain the universal tribological mechanism of diamond films. Fourthly, the dynamic mechanical sealing tests are conducted to clarify the relationship between the liquid media property, the sealing pair property, and the working condition, which can provide effective guide on the successful industrialization applications of diamond coated mechanical seals.

为解决苛刻介质工况环境中机械密封环端面易磨损和可靠性差的难题，以实现端面改性升级为目标，本项目对机械密封环端面梯度金刚石薄膜的沉积与耐磨减摩机理展开研究，主要包括四个方面：首先，通过沉积工艺参数闭环控制系统的开发，和基于流-固-热耦合模型的沉积区域物理场的仿真优化，实现密封环端面大面积金刚石薄膜的优质均匀沉积；其次，创新引入梯度MCD/FGD/NCD/UNCD薄膜，突破单层金刚石薄膜的性能局限，揭示金刚石薄膜残余内应力的形成机制与控制原理，实现在密封环端面高效沉积光滑、耐磨、且膜基结合紧密的金刚石薄膜；再次，采用摩擦试验研究薄膜在强磨粒磨损、酸性、碱性和温水介质及变工况条件下的摩擦成膜机理、磨损规律和化学反应，揭示苛刻介质工况环境中金刚石薄膜的普适性耐磨减摩机理；最后，通过机械密封试验阐明介质和配副密封材质特性与使用工况参数的内在关系，为金刚石涂层机械密封环的成功产业化应用提供有效指导。

为解决苛刻介质工况环境中机械密封环端面易磨损和可靠性差的难题，本项目通过开展均匀稳定大面积薄膜沉积系统的搭建，微纳米复合梯度金刚石薄膜的沉积，机械密封环端面金刚石抛光性能的研究，强磨粒磨损、和酸、碱性介质中金刚石薄膜摩擦学性能的研究，干摩擦条件下金刚石薄膜涂层机械密封环密封性能的测试，以及在铝矿浆输送泵上金刚石薄膜涂层机械密封环使用性能的评价六方面的工作，获得了金刚石薄膜涂层机械密封环的优化涂层和抛光工艺，阐明了金刚石薄膜在强磨粒磨损、酸性、碱性介质中的磨损机理，获得了配对微纳米复合梯度金刚石薄膜碳化硅机械密封环的密封性能最佳的结论。