轴棒法编织C/C复合材料的超声速火焰烧蚀性能

Ablation Properties of Axial Carbon Rod C/C Composites in High Velocity Oxygen Flame

关键词:  轴棒法  C/C复合材料  气氧/煤油  超声速火焰  烧蚀性能 

Key words:  Axial carbon rod  C/C composite material  GO₂/kerosene  High velocity oxygen flame  Ablation properties

摘要:

为了研究轴棒法编织、高压浸渍-碳化致密工艺(HPIC)及高温处理工艺制成的高密度的碳/碳(C/C)复合材料在火箭发动机中的烧蚀性能,使用气氧和煤油超声速(HVO)火焰对复合材料进行含铝工况烧蚀/侵蚀实验,烧蚀时间为30s；对比研究了复合材料在有、无含铝粒子侵蚀时烧蚀性能的差别；分别用扫描电镜、微CT和表面能谱分析了不同工况烧蚀表面的形貌和成分。结果表明,在不同的烧蚀工况下,材料的表面粗糙度不同,微观形貌和烧蚀率也有很大差异；复合材料在无粒子侵蚀工况下的线烧蚀率和质量烧蚀率的平均值分别是0.0318mm/s和0.0319g/s,烧蚀表面呈竹笋状和毛絮状,热化学烧蚀起主导作用；有粒子侵蚀时的线烧蚀率和质量烧蚀率的平均值分别是0.0516mm/s和0.0353g/s,烧蚀表面呈钝竹笋状,纤维从根部断裂,热化学烧蚀和机械剥蚀同时起作用；在纤维和基体表面有Al₂O₃粒子沉积；含铝烧蚀/侵蚀的线烧蚀率是不含铝烧蚀的1.6倍,质量烧蚀率的1.1倍。在烧蚀区的内部,基体碳受热后开裂,而碳纤维与基体碳间的界面相受热后无明显变化。 

Abstract:

In order to study the ablation properties of axial carbon rod carbon/carbon composites, which were prepared by high pressure impregnation/ carbonization(HPIC) and high temperature combined process, the gas O₂/kerosene high velocity oxygen(HVO) flame were used to ablate the composites. Different Al₂O_3particles were combined with the flame in different experiments, and the ablation duration time was 30s. The surfaces of the samples ablated in different conditions were investigated by using scanning electron microscopy, Micro-CT and energy dispersive spectroscopy. The results show that the micro-morphologies are different in different conditions.When no particles in the flame, the linear and mass ablation rates of C/C composites are 0.0318mm/s and 0.0319g/s, respectively.The surface comes into being bamboo shoot and floccule, and the thermo-chemical ablation plays a leading role. Whereas the linear and mass ablation rates are 0.0516mm/s and 0.0353g/s,respectively when Al₂O_3particles are combined in the flame. The surface comes into being thick bamboo shoot, and the fibres break off in bottom,while thermo-chemical ablation and particle erosions all play roles. Some Al₂O_3particles deposit on the surface. The linear loss rate is 1.6times to the no particles’ ablation, and the mass loss rate is 1.1times to the no particles’. Inside the ablation area, C matrix cracks in heat, while the interface is steady.