Microstructure and ablation properties of ZrC nano-powder modified C/C-SiC composites
In order to improve the ablation resistance of C/C-SiC composites,ZrC nano-powder modified C/C-SiC composites were prepared by the reactive melt infiltration(RMI)with ZrC nano-powder and Si powder as raw materials.X-ray diffraction,scanning electron microscopy,and energy dispersive spectrometer were used to investigate the effects of ZrC nano-powder contents on the microstructure and ablation properties of C/C-SiC composites.The results indicate that with the increase of ZrC nano-powder content,the porosity of the composite increases,but the density changes little.Meanwhile,part of ZrC nano-powders are diffusely distributed in the SiC matrix,and part of them are agglomerated.After ablation for 30 s,when the mole fraction of ZrC nano-powder is 6％,the composite exhibits the lowest mass and linear ablation rates of 2.0 mg/s and 3.9 μm/s,respectively.And with the increase of ZrC nano-powder content,the content of ZrO2 formed during ablation increases,this leads to a notable enhancement in the pinning effect on SiO2,effectively improving the ablation resistance of C/C-SiC composites.
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