C/C复合材料在再入模拟环境中烧蚀性能研究

Ablation Characteristics of C/C Composites In Reentry Simulation Conditions

关键词:  轴棒法C/C复合材料  再入  热等离子体  烧蚀率  微观形貌

Key words:  Axial carbon rod C/C composite material  Reentry  Thermal plasma  Ablation rate  Micromorphology

摘要:

为了研究轴棒法编织的高密度碳/碳(C/C)复合材料在再入飞行时的烧蚀性能,采用热等离子体地面模拟再入烧蚀系统对C/C复合材料进行烧蚀试验。试验中分别采用氮气(N2)、氧气(O₂)和空气作为工作气体,对比研究C/C复合材料在不同环境中的烧蚀率和烧蚀性能。结果表明,三种情况下试样的烧蚀率和微观形貌有很大差异；纯氧气时氧化反应的线烧蚀率和质量烧蚀率分别为0.0423mm/s和0.0451g/s,大于纯氮气时氮化反应的0.0314mm/s和0.0338g/s,也大于空气成分时复合反应的0.0215mm/s和0.0208g/s；在试样烧蚀的热影响区发生轻微开裂；三种工况下的烧蚀机理不同,分别是碳的升华、碳的氧化和碳氮反应的某种组合。

Abstract:

In order to study the ablation characteristics of axial carbon rod C/C composites,the ablation experiments were conducted by reentry simulation condition ablation system based on thermal plasma. The nitrogen(N2),oxygen(O₂)and air were taken as the operation gases,and the ablation characteristics and ablation rates of the specimens in different conditions were compared. The results show that the micro-morphologies and the ablation rates are different in three operation gases conditions. The linear and mass ablation rates are listed as follows: oxidation of O₂(0.0423mm/s and 0.0451g/s)> nitridation of N2(0.0314mm/s and 0.0338g/s)> composite reactions of air (0.0215mm/s and 0.0208g/s). There are some tiny cracks in thermal influencing areas,and the ablation mechanisms of the C/C composites in three operation gases conditions are differents. They are some combinations of sublimation of carbon,carbon oxide and carbon nitrogen reaction.