不同热解碳界面层厚度 C/ZrC-SiC 复合材料烧蚀性能及其机理

Composites of C/ZrC-SiC with pyrolytic carbon (PyC) interlayers of different thickness, namely, S5-C/ZrC-SiC, S15-C/ZrC-SiC, S30-C/ZrC-SiC, and S50-C/ZrC-SiC were prepared by adjusting the deposition time. The variation of density, microstructure and ablation properties of C/ZrC-SiC composites with interlayer PyC of different thickness was systematically studied. The results show that with the increasing thickness of interlayer PyC, the density and porosity of C/ZrC-SiC composites decrease, but the content of the pioneer impregnation pyrolysis ZrC matrix decreases first and then increases. As for 20 s short time oxyacetylene ablation, S30-C/ZrC-SiC composites presents the best ablation performance, and its mass ablation rates and linear ablation rates are -0.84 mg/s and 3.00 μm/s, respectively; while for 60 s long time cycle ablation test, S15-C/ZrC-SiC composites has the best ablation performance, and its mass ablation rates and linear ablation rates are 1.22 mg/s and 3.80 μm/s, respectively. The mechanism for the 20 s oxyacetylene ablation of C/ZrC-SiC composites may be ascribed to mechanical erosion, while for the second 60 s oxyacetylene ablation of C/ZrC-SiC composites, the ablation mechanism may be described as that the ablation process changes from mechanical erosion to thermo-physical and thermo-chemical ablation.