基体改性C／C—HfC—HfB2-SiC复合材料抗烧蚀性能研究

以碳化铪有机前驱体、硼化铪有机前驱体和聚碳硅烷混合溶液为浸渍剂，采用化学气相渗透（CVI）和液相浸渍-裂解（PIP）T艺制得了准3DC／C-HfC-HfB2-SiC碳陶复合材料。采用电弧风洞结合扫捕电子显微镜（SEM）和X射线衍射分析（XRD）对复合材料的结构及氧化失效行为进行了初步探讨。结果表明，高密度的基体改性C／C．HfC—HfB2-SiC复合材料具有良好的抗烧蚀性能，复合材料在2300K／600S电弧风洞（含水5％）试验条件下的质量烧蚀率和线烧蚀率分别仅为1．22×10^-6g／（cm^2·s）和1．33X10^-5mm／s。密度和温度对复合材料抗烧蚀性能影响较大，密度从2．63g／cm^3增加到3．75g／cm^3时，复合材料在2300K条件下的线烧蚀率降低了3个数量级，当温度从2300K升高的2400K时，高密度复合材料的线烧蚀率增加了约1000倍，烧蚀过程中较高密度的复合材料表面容易形成更为致密的氧化膜是其具有良好的抗氧性能的重要因素。

Ablation Behaviors of Matrix Modified C/C- HfC-HfB2 -SiC Composites

Abstract： The quasi three dimension carbon/carbon-hafnium carbide-hafnium diboride-silicon carbide （3D C/C-HfC- HfB2-SIC） composites, which made use of a hybrid precursor contained polycarbosilane and organic HfB2 polymeric pre- cursor and organic HfC polymeric precursor, were prepared through chemical vapor infiltration （CVI） and then treated by precursor infiltration and pyrolysis （PIP） process. The components and microstructures of the ab/ated samples were char- acterized by scanning electron microscopy （SEM） and X-ray diffrac, tion （XRD） analysis, respectively. The results show that C/C-HfC-HfB2-SiC composites with high density have wonderful anti-ablation properties. After ablation at 2 300 K （ 5 % H2 0 contained） for 600 s via are heated wind tunnel test, the mass and linear ablative rate is as low as 1.22 x 1 0 -6 g/（cm2 · s） and 1.33 x 10-5 ram/s, respectively. Density and temperature were two very important factors to anti-abla- tion of the composites. The linear ablative rate of the composites decreased three orders of magnitude when density of the composites increased from 2.63 g/cm3 to 3. 75 g/cm3. And the linear recession rate rised by one thousand times from 2 300 K to 2 400 K. It is found that during ultra-high temperature stage, a high density membrane could easier got on the surface of the high density composites. It could effectively cover the ablation surface and therefore promote its anti-ablation property.