铌铪合金表面硅化物涂层的高温失效行为分析  

Failure behavior analysis of silicide coating on Nb-Hf alloy at surface high temperature

作　　者：潘兆义 赵青芮 王国强 蔡刚 宋国新 PAN Zhaoyi;ZHAO Qingrui;WANG Guoqiang;CAI Gang;SONG Guoxin(Xi'an Space Engine Company Limited, Xi'an 710100, China)

机构地区：[1]西安航天发动机有限公司,陕西西安710100

出　　处：《火箭推进》2019年第2期66-73,共8页Journal of Rocket Propulsion

摘　　要：铌铪合金为轨姿控液体火箭发动机推力室身部主要结构材料,在高温有氧的工作环境中易发生氧化粉化,必须在合金表面涂覆高温抗氧化涂层。通过分析铌铪合金表面硅化物涂层的高温氧化、高温热震、瞬时高温烧蚀和热试车行为,阐述高温条件下的氧化失效行为。试验结果为:涂层1 800℃以下氧化条件下,表面形成致密的二氧化硅氧化膜,使得涂层的氧化寿命大于2 h;1 800℃以上的超高温氧化条件下,高温热冲击作用,涂层内部形成大量的烧蚀型网格结构,表面未形成二氧化硅氧化膜,氧化寿命小于10 s;热试车考核中,涂层满足推力室外壁面温度1 350℃以下的使用工况,抗氧化能力较好,随着氧化温度升高,涂层高温抗氧化能力迅速衰减。Nb-Hf alloy is the main structured material of the trust chamber in orbit-attitude controlled liquid rocket engine.The Nb-Hf alloy is easily oxidized in high temperature and aerobic working environment, so it is necessary to coat the alloy surface with high temperature oxidation resistant.In this paper, the oxidation failure behavior of silicide coating on Nb-Hf alloy surface at high temperature is expounded by analyzing its high temperature oxidation, high temperature thermal shock, instantaneous high temperature ablation and hot test behavior.The test results are as follows: under the oxidation conditions below 1 800℃, a dense SiO 2 film is formed on the surface of the coating, so that the oxidation life of the coating is longer than 2 h;Under the ultra-high temperature oxidation condition above 1 800℃, a large amount of ablative grid structures are formed inside the coating due to high temperature thermal shock, and no silica oxide film is formed on the surface and the oxidation life is less than 10 s.In the hot test, the oxidation resistance of the coating is better when the outer wall temperature of the thrust chamber is below 1 350℃, while the oxidation resistance of the coating decreases rapidly with the increase of the coating temperature.

关 键 词：铌铪合金 硅化物涂层 瞬时高温 氧化行为 

分 类 号：V252[一般工业技术—材料科学与工程]