Nb-Si基合金是最具潜力作为制造1200℃以上航空发动机叶片的金属基结构材料，但高温抗氧化性差是制约其工程应用的主要瓶颈问题，迫切需要开展高温防护涂层的失效及热防护机理研究。本项目针对新一代燃气涡轮发动机用1200℃以上超高温涂层，研究Mo-Si-B涂层的相平衡关系与相转变特征，以及合金化元素对相组成和相稳定性的影响规律，阐明温度、氧化及互扩散对Mo-Si-B涂层的成分及微观组织的影响机制；研究温度、涂层成分及微观组织结构演变对涂层高温氧化热力学与动力学、氧化膜的组织结构、内应力及其破坏与再生等影响规律，涂层服役过程中互扩散区的组织演变规律，提出Nb-Si合金表面Mo-Si-B高温防护涂层失效机理及涂层材料/Nb-Si基合金体系中合金元素热扩散与阻扩散机理；揭示复合涂层在抗氧化和抑制元素互扩散等功能实现机制，提出超高温合金表面长寿命防护功能的涂层材料与结构的设计理论与方法。

Nb–Si based alloys are great potential structural materials for aero-engine blades at temperatures above 1200°C. However, a major barrier to the high temperature applications of the Nb–Si based alloys is their poor oxidation resistance. Therefore, it is required to investigate failure and thermal protection mechanism of the coating on the Nb-Si based alloys. The aim of the study is to investigate the phase equilibrium, phase transitions of the Mo-Si-B coating, as well as the effect of adding alloying elements of the coating on the phase composition and stability. The impact of oxidation and mutual diffusion on the coating composition and microstructure will be explored. The influence of temperature, coating composition and microstructure evolution on thermodynamics and kinetics of the coating, oxide microstructure, internal stresses, destruction and regeneration of the oxide formed on the coating will be studied. Coating failure mechanism will be proposed. Microstructure evolution of the mutual diffusion zone and diffusion mechanism will be clarified. The oxidation resistance mechanism and diffusion inhibition mechanism will be revealed. This project lays the foundation for developing the material and structure design theory and method for the protective coating on Nb–Si based alloys