HfC涂层性能研究和制备工艺

Research on HfC Coating Performance and Preparation Process

碳基复合材料(C/C、C/SiC)具有高比强度、高比模量、低密度、低热膨胀系数、耐腐蚀、耐热震的优良高温力学性能,被认为是最有前景的高温结构材料之一。但碳基复合材料一般在500℃开始发生氧化,而且存在较大孔隙率,无法实现高压密封,这极大地限制了碳基复合材料应用前景。在高温高压气流冲刷环境下,超高温陶瓷基保护涂层可以有效地抑制碳基复合材料(C/C、C/SiC)中碳成分的降解,工件在极端环境下可以更加稳定地工作,延长使用寿命。其中碳化铪(HfC)的熔点高达3890℃,为已知单一化合物中熔点最高者,热导率仅为5.6 W/(m·K),维氏硬度高达26 GPa,耐烧蚀性好,同时还具有低导热系数、低氧扩散系数、低表面蒸汽压。作为火箭喷嘴和鼻锥等极端耐热部件的抗氧化烧蚀涂层已获得应用。综述了超高温陶瓷HfC涂层材料的研究背景、基本性质、制备工艺、抗氧化/烧蚀机理和热膨胀系数(CTE)失配问题,并指出了超高温陶瓷HfC涂层材料目前存在的挑战,同时对未来的发展趋势做出了展望。

Carbon-based composite materials(C/C,C/SiC)have high specific strength,high specific modulus,low density,low thermal expansion coefficient,corrosion resistance,thermal shock resistance,and are considered as one of the most promising high temperature structural materials.However,carbon-based composites generally begin to oxidize at 500℃,and have large porosity,which cannot achieve high pressure sealing,which greatly limits the application prospects of carbon-based composites.Under the environment of high temperature and high pressure air scour,ultra high temperature ceramic base protective coating can effectively inhibit carbon composite material(C/C,C/SiC)in the degradation of carbon composition.The melting point of hafnium carbide(HfC)is as high as 3890℃,which is the highest in the known single compound,the thermal conductivity is only 5.6 W/(m·K),Vickers hardness is as high as 26 GPa,good ablative resistance,but also has low thermal conductivity,low oxygen diffusion coefficient,low surface vapor pressure.Oxidation resistant ablative coatings have been used as extremely heat resistant components such as rocket nozzles and nose cones.In this paper,the research background,basic properties,preparation technology,ablation mechanism and coefficient of thermal expansion are summarized.The current challenges of ultra temperature ceramic HfC coatings are pointed out,and the development trend of ultra temperature ceramic HfC coatings is forecasted.