利用自建的可控气氛感应加热超高温氧化装置研究了ZrC、ZrC-TaC颗粒增强石墨基复合材料在1900和2100℃下空气及0.2×103Pa的纯氧气中的氧化行为.结果表明,石墨以及颗粒增强石墨基复合材料的径向线度随氧化时间直线减小,在1900和2100℃下的氧化烧蚀速率:石墨为3.4和4.3 mm/s,C-ZrC为1.9和2.4 mm/s,C-ZrC-TaC为1.4和2.0 mm/s.添加增强相后使得石墨在1900和2100℃的空气中氧化540 s后烧蚀速率分别降低了60%和54%.在2100℃下,C-ZrC在0.2×103Pa O2中的氧化速率是其在空气中的2倍多.综合考虑材料的氧化动力学规律以及氧化温度、气氛的总压及氧分压的影响,提出了超高温氧化边界层扩散控制模型.%The oxidation resistance of ZrC and ZrC-TaC reinforced graphite was tested at 1 900℃ and 2 100℃ in air and 0.2×105 Pa pure oxygen by using an ultra-high temperature oxidation facility with induction heating. The experimental results indicate that the radius of the cylinder graphite and graphite-based composites decreased with oxidation time linearly. The corresponding ablation rate is 3. 4/4. 3 mm/s for graphite, 1. 9/2. 4 for C-ZrC and 1. 4/2.0 for ZrC-TaC/C- ZrC-TaC at 1900℃ and 2 100℃ , respectively. It is found that the samples encountered more severe oxidation under pure oxygen environment. For example , the oxidation rate of C-ZrC in pure oxygen is more than twice of that in air at 2 100℃ . An oxidation model with oxygen inward diffusion through boundary layer as predominant step is proposed to explain the oxidation law and the influence of temperature, total gas and oxygen partial pressure.
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