宽温域自适应TiCN基金属陶瓷润滑体系构建及调控机理

High speed dry cutting is an important means to realize the development of high efficiency, precision and green manufacturing. However, the high demand for wear resistance and self-lubrication performance of the cutting tool in the wide temperature range limited the developing of the technology. In this work, we used TiCN-based cermet, a common cutting tool material, as matrix to form new kind of composite to realize adaptive lubrication in a wide temperature range. An Ag@SiO2 core-shell structure microcapsule, prepared by sol-gel method, was used to control the Ag phase diffusion rate. The mechanical properties of the composite were investigated without sacrificing the self-lubrication performance. Effects of size, surface morphology and shell wall thickness on the broken behavior of the microcapsule were studied with different force or heat stimulations. The adaptive mechanism of the composites with the formation of oxide lubricating film, from the oxidization of Ag with Mo2C and VC in high temperature, was also studied. The controllable release rate of Ag was helpful to increase the service life of the composites under the thermal-cycle working condition. Thereby, this project provides a new method to develop self-lubricating composites in a wide temperature range. The composites are prospected to improve the performance and service life of aerospace high-temperature lubricating components and high-speed dry cutting tool materials.

高速干切削技术实现加工制造向高效、精密、绿色方向发展的重要手段，而刀具材料的高温耐磨性和宽温域连续自润滑性能是限制该技术进一步推广的瓶颈之一。本项目基于溶胶凝胶法制备Ag@SiO2核壳结构纳米微胶囊技术，将其与切削刀具材料TiCN基金属陶瓷进行复合，研制具有宽温域自适应且润滑相扩散速率可控的新型TiCN基复合材料体系，探索力学性能和宽温域自润滑协同提高的材料制备方法；揭示微胶囊尺寸、表面形貌及壳壁厚度与力/热刺激下的壳壁破裂行为的内在关联，实现摩擦中对银单质的可控释放；探讨Ag与金属陶瓷基体中Mo2C、VC在摩擦氧化下的宽温域自适应润滑机制，实现宽温域下金属陶瓷的自适应连续润滑；阐明Ag可控释放与材料在高低温循环工况下材料使用寿命的对应关系。本项目开发的宽温域连续自润滑体系可为航空航天高温润滑部件及高速干切削刀具材料的优化设计和性能提升提供新思路。

TiCN基金属陶瓷具有强度高、红硬性好、耐磨损等优异性能，成为制备耐磨部件的重要材料，然而其自润滑性较差，宽温域工况下的摩擦磨损问题成为限制其广泛应用的瓶颈。本项目从研制新型TiCN基金属陶瓷入手，以金属Ag、BaF2和纳米金刚石为润滑添加剂，采用放电等离子烧结技术，制备了TiCN-MoC-Ni-Ag、TiCN-MoC-Ni-BaF2、TiCN-MoC-Ni-Ag-BaF2和TiCN-WC-Ni-ND四组TiCN基复合材料体系，并对其微观结构、力学性能和宽温域摩擦学性能进行分析测试，揭示了TiCN基金属陶瓷的高温磨损行为和不同润滑相在宽温域工况下的润滑机理，阐明了不同润滑添加剂的适宜工作温度，提出了不同润滑相在宽温域下的协同润滑作用机制，开发了具有宽温域自润滑性能TiCN-基的金属陶瓷材料。本项目共发表SCI收录论文7篇，申请并授权中国发明专利2件。本项目研究结果将促进具有宽温域自润滑TiCN基金属陶瓷的研制，为宽温域自润滑金属陶瓷在航空航天、高速干切削刀具等行业中的工程化应用提供理论和实践指导。