基于铝酸锶的润滑特性探索新型高温自润滑复合材料的摩擦行为

Aiming at the continuous lubricating properties of high temperature self-lubricating materials suitable for wide temperature and temperature cycle tribological application in modern aviation and advanced jet engines, the friction behaviors of new high temperature self-lubricating composites based on the lubrication function of strontium aluminate were investigated. In the view of the method for the formation of the lubricating substance by solid phase reaction, by using Powder metallurgy-Vacuum sintering technology, through the regulation of the content of SrCO3 and sintering process, a series of NiCr-Al2O3 cermet self-lubricating composites containing single or two or more different stoichiometric strontium aluminum were prepared according to the decomposition characteristics of SrCO3 at high temperature. The effect of sizes, distribution and morphologies of strontium aluminate on the composites structure, mechanical properties and tribological properties would be investigated. The interactive influence of the phase composition, surface structure and grain reorientation on the friction surfaces under different temperature on the tribological properties of the composites would be revealed. The interaction of strontium aluminum and temperature-induced tribochemical effects on the formation of friction layers and the transfer films would be explored to clarify the lubricating and wear mechanisms in a wide temperature range. The design and principles of the continuous lubricating composites in a wide temperature based on formation of the lubricating substance by solid phase reaction would be built and the key preparation technology of the composites would be established as well. The study will be expected to provide a scientific basis and theoretical guidance for new high temperature self-lubricating composites.

针对航空航天等领域急需的高温润滑材料的宽温域和温度循环下连续润滑问题，开展基于铝酸锶的润滑特性探索新型高温自润滑复合材料的摩擦行为研究。采用粉末冶金真空热压烧结技术，基于固相反应生成润滑物质的思路，借助碳酸锶（SrCO3）的高温分解特性，通过SrCO3含量和烧结工艺的调控，制备一系列的含有单一或两种以上不同化学计量比铝酸锶的NiCr-Al2O3金属陶瓷自润滑复合材料。深入研究铝酸锶的尺寸、分布和形态对材料组织结构、力学性能和摩擦学性能的影响，揭示不同温度下摩擦表面的相组成、结构、晶粒取向等与材料润滑性能之间的相互关系规律，探讨铝酸锶和温度诱导的摩擦化学反应产物的交互作用对摩擦层和转移膜形成的影响机制，阐明材料的宽温域连续润滑和抗磨机理，提出通过固相反应生成润滑物质实现润滑功能的复合材料设计构筑原则和依据，并形成关键制备技术，为新型高温自润滑复合材料的研制提供科学依据和理论指导。

通过烧结温度和SrCO3含量的调控，基于SrCO3和Al2O3之间的固相反应，研究了不同化学计量比铝酸锶及其复配（monoclinic-SrAl4O7、SrAl12O19、monoclinic-SrAl4O7/ orthorhombic-SrAl4O7、orthorhombic-SrAl4O7、SrAl12O19/Sr4Al14O25、SrAl12O19/ Sr4Al14O25/Sr4Al2O7、Sr4Al14O25/Sr4Al2O7）对NiCr-Al2O3复合材料的组织结构、硬度及宽温域摩擦学性能的影响，结合不同温度下磨损表面的组成成分，探索了不同化学计量比铝酸锶及其复配与摩擦化学反应产物之间的交互作用对摩擦层及转移膜形成的影响机制，并探讨NiCr相，Al2O3相和不同化学计量比铝酸锶及其复配之间的相互关联，阐明不同温度下磨损表面的组成成分、摩擦化学与摩擦学性能的演变规律，揭示了不同温度下含有不同化学计量比铝酸锶及其复配的NiCr-Al2O3复合材料的摩擦磨损机理，提出通过固相反应生成润滑物质实现润滑功能的复合材料设计构筑原则。本项目所得的基于固相反应制备的不同化学计量比铝酸锶及其复配的高温润滑机理，对于航空发动机相关运动部件的室温-高温连续润滑问题的研究具有重要的实际价值和理论意义，为新型高温自润滑材料的研制提供科学依据和理论指导。