基于氧扩散阻挡机制的耐高温自润滑TiAlSiN/a-C多层薄膜设计及其高温自润滑行为

Amorphous Carbon-based film(a-C) is widely used in aerospace,automobile engine, etc. However, as the service temperature is increasing, the high temperature self-lubricating performance need to be improved urgently for the temperature between 200 and 600 degree, and the high temperature self-lubricating mechanism also need to be researched deeply. It is discovered in our pre-research that the key of improving service temperature is the oxidation diffusion barrier mechanism of the continuous oxide layer on surface. According to this, based on the oxygen diffusion barrier mechanism of high temperature oxidation resistance film, this project will modify the microstructure of a-C film with the high temperature oxidation resistance film as oxygen diffusion barrier by the technology of physical vapor deposition. We will develop the preparation of TiAlSiN/a-C multilayer films, investigate the influence of duty cycle, element content, microstructure on the high temperature performance of TiAlSiN/a-C multilayer films, and finally to obtain the TiAlSiN/a-C multilayer films with excellent high temperature self-lubricating property. We will reveal the influence of oxygen diffusion barrier behavior, the oxidation rate constant Kp and the high temperature activation energy E of film on the high temperature self-lubricating performance; realize the diffusion behavior of oxygen to films in high temperature by using the moleculor dynamic simulation, provid scientific judgment for the quantitative evaluation and prediction of high temperature self-lubricating performance of films, establish eventually the high temperature self-lubricating theory based on the oxidation diffusion barrier mechanism of TiAlSiN/a-C films.

非晶碳基薄膜（a-C）广泛应用于航空航天、汽车发动机等领域，但随着使用温度的上升，亟需提高其200至600℃之间的高温自润滑性能，并且其高温自润滑机理也有待进一步深入研究。课题组前期的研究发现，表层致密氧化物层的氧扩散阻挡机制是提高a-C使役温度的关键。本项目采用物理气相沉积技术，以高温抗氧化薄膜的氧扩散阻挡机制为切入点，利用高温抗氧化薄膜作为a-C薄膜的氧扩散阻挡层，研究调制周期、元素含量、微观组织等对薄膜高温性能的影响，获得具有优良高温自润滑性能的TiAlSiN/a-C多层薄膜。揭示氧扩散阻挡行为及氧化速率常数、高温氧化活化能对TiAlSiN/a-C多层薄膜高温自润滑性能的影响规律，通过分子动力学模拟阐明氧原子在高温环境下向薄膜内部的扩散行为，为薄膜材料高温自润滑性能定量评价及预测提供科学判据，最终建立TiAlSiN/a-C薄膜基于氧扩散阻挡机制的高温自润滑理论。

非晶碳基薄膜（a-C）具有优良的常温摩擦学性能，但中高温下由于结构转变，其摩擦学性能变差。本项目采用物理气相沉积技术，以高温抗氧化薄膜的氧扩散阻挡机制为切入点，利用高温抗氧化薄膜作为a-C薄膜的氧扩散阻挡层，研究了调制周期、元素含量、微观组织等对薄膜性能的影响。发现C及Al的含量对薄膜摩擦学及高温抗氧化性能有较大影响。通过多层及梯度设计理念，获得了具有优良性能的TiAlSiN/a-C多层薄膜，实现膜基强结合及薄膜可控制备。利用热动力学方法将薄膜氧化过程用氧化速率常数Kp及氧化活化能E进行量化。对摩擦过程中接触界面的成分、结构等进行研究，并对薄膜自润滑机制进行了总结，为薄膜材料高温摩擦性能定量评价及预测提供了科学判据。