材料期刊网

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360～650℃范围内的空气中的氧化性能.发现在360℃以下，试样未发生明显地氧化；在450～500℃恒温氧化后试样中发生C沉积；在600℃恒温氧化25 min后，试样完全氧化.对其进行了在250～850℃的空气中热重和差热分析结果表明，NbCx-C网状纤维在400℃以后开始明显地氧化并增重，480℃以后反应增重加速，570℃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20.6 mass％.

The oxidation character of NbC was studied from a thermoanalytical viewpoint first. The oxidation of NbCx(x = 0.98) -C three dimensional(3 -D) netted fibers was carried out isothermally at temperatures of 360 to 600℃ in air. It was found that no oxidation taken place below 360℃. Amorphous carbon was precipitated out during isothermal oxidation at 450 and 500℃ . The NbCx in sample was oxidized completely after isothermal oxidation at 600℃ for 25 minutes. The thermogravimetry (TG) and differential thermal analysis (DTA) on oxidation of samples was carried out at temperature of 250 to 850℃ at a heating rate of 10℃/min. in air. The results indicated that NbCx - C netted fibers were oxidized obviously above 400℃ in the air. The weight gain increased quickly at 480℃ and reached maximum at 570℃, and then decreased quickly. The reason is that carbon is oxidized continuously. According to the weight loss in the end, it was calculated that the amount of carbon contained in the sample was about 20.6 mass %.