低密度碳纤维复合材料耐高温抗氧化技术研究

High Temperature Oxidation Resistance of Low Density Carbon Bonded Carbon Fiber Composite

低密度碳纤维复合材料具有轻量化、耐高温、低热导等优异特性,在航空航天热防护领域有较大的应用潜力。为了提高低密度碳纤维复合材料高温抗氧化性能,本研究设计并研制了耐高温低密度抗氧化碳纤维复合材料。首先,采用气相沉积工艺对传统低密度碳纤维复合材料进行了强韧化处理,沉积210 h时后材料抗拉强度和抗压缩强度分别提高275%和341%。其次,采用刷涂浸渍和高温原位烧结方法设计并制备了双层超高温抗氧化涂层,采用高温马弗炉对材料在空气环境、不同温度下的高温抗氧化性能进行了测试。结果表明,在1700~1750℃考核条件下材料表现出优异的抗氧化性能,增重率为1.1×10^-5~1.5×10^-5 g/(cm^2·s),表面形成的致密氧化硅氧化膜和氧化铪镶嵌氧化硅氧化膜为材料提供了优异的抗氧化性能。

Low density carbon bonded carbon fiber(CBCF)composites are thought to be attractive candidates for thermal insulation applications in aerospace due to their unique properties such as low density,high temperature stability and low thermal conductivity.In the present work,an anti-oxidation low density carbon bonded carbon fiber composite was designed and fabricated for high temperature application.Firstly,PyC coating was deposited uniformly on the surface of carbon fibers to improve the mechanical properties of CBCF through CVI process.After deposited for 210 h,the tensile strength and pressure strength in thickness are increased by 275%and 341%,respectively.Then,a dual-layer coating was designed and prepared to improve the oxidation resistance of CBCF.High temperature oxidation properties at different temperatures were tested by a high temperature muffle furnace in air.The results show that the as-prepared oxidation coating can protect composites effectively under high temperature oxidation conditions.After oxidation at 1700~1750℃ for 300~360 s,the mass ablation rates are about 1.1×10^-5~1.5×10^-5 g/(cm2·s).The formation of a dense glass layer of SiO2 or SiO2 embedded with HfO2 is responsible for the good ablation resistant.