(1.School of materials Science and Engineering, Northwestern Polytechnical University, Xin 710072, China)(2 Xi’an Aerospace Composites Research Institute, Xin 710025, China.)
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DOI:
10.7502/j.issn.1674-3962.2013.11.03
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Abstract:
The quasi three dimension carbon/carbon-hafnium carbide-hafnium diboride杝ilicon carbide (3D C/C-HfC-HfB2-SiC) composites, which made use of a hybrid precursor contained polycarbosilane and organic HfB2 polymeric precursor 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 ablated samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis，respectively. The results show that C/C-HfC-HfB2-SiC composites with high density have wonderful anti-ablation properties. After ablation at 2300k (5wt.% H2O contained) for 600s via arc heated wind tunnel test, the mass loss and linear recession rate is as low as 1.22?0-6 g/(cm2穝) and 1.33?0-5mm/s, respectively. Density and temperature were two very important factors to anti-ablation of the composites. The linear recession rate of the composites decreased three orders of magnitude when density of the composites increased form 2.63g/cm3 to 3.75g/cm3. And the linear recession rate rised by one thousand times from 2300k to 2400k. 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