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对NbC材料在空气中的氧化特性进行热力学分析 ,并采用恒温氧化法研究了NbCx(x =0 .98) -C网状纤维在 36 0～ 6 5 0℃范围内的空气中的氧化性能 .发现在 36 0℃以下 ,试样未发生明显地氧化 ;在 45 0～ 5 0 0℃恒温氧化后试样中发生C沉积 ;在 6 0 0℃恒温氧化 2 5min后 ,试样完全氧化 .对其进行了在 2 5 0～ 85 0℃的空气中热重和差热分析结果表明 ,NbCx -C网状纤维在 40 0℃以后开始明显地氧化并增重 ,480℃以后反应增重加速 ,5 70℃时增重达最大值 ,之后体系开始迅速减重 ,原因是C继续氧化 .据试样的最后失重值计算出其中含C量为 2 0 .6mass % .
The oxidation behavior of NbC in air was investigated. The oxidation behavior of NbCx (x = 0.98) -C mesh in air at 36 0-650 ℃ was investigated by the constant temperature oxidation method. It was found that the sample did not oxidize obviously below 36 0 ℃. After the isothermal oxidation at 45 0-500 ℃, C deposition occurred in the sample and the sample was completely oxidized after constant temperature oxidation at 600 ℃ for 25 min. The results of thermogravimetry and differential thermal analysis in air at 250 ~ 85 0 ℃ showed that the NbCx-C network fibers obviously oxidized and increased weight after 40 0 ℃, and the weight gain accelerated after 480 ℃, 5 At 70 ° C, the weight gain reached a maximum, after which the system started to lose weight quickly, because C continued to oxidize, and the C content was calculated to be 20.6% by mass based on the final weight loss of the sample.