C/C复合材料的SiC/Si-B4C涂层在500~1 500℃的抗氧化机制
Oxidation resistance of SiC/Si-B4C coating on C/C compositesat 500-1 500℃ in air

为提高C/C复合材料的宽温域抗氧化性能，开发了一种新型SiC/Si-B4C复合涂层，利用热重法对C/C复合材料的SiC/Si-B4C复合涂层进行氧化试验，研究了试样从室温到1 500℃的氧化行为，在1 500℃保温2 h后，试样增重仅为2.21%。分别对SiC、Si和B4C三种粉体进行了不同温度（500~1 500℃）的氧化试验，分析了涂层各组分的高温氧化行为，阐明了SiC、Si和B4C的有效抗氧化温域，通过氧化动力学计算得到SiC和Si的氧化活化能分别为196.7 kJ/mol和167.3 kJ/mol。结果表明，SiC/Si-B4C涂层中各组分的抗氧化性能形成了良好的协同作用，复合涂层具有良好的宽温域自愈合能力，在600~1 500℃范围内表现出良好的抗氧化性能。 In order to improve the oxidation behavior of C/C composites in a wide range of temperature, a new SiC/Si-B4C coating was developed. The oxidation resistant mechanism of the SiC/Si-B4C coated composites was studied by thermogravimetric analysis in the temperature range from room temperature to 1 500℃. After oxidation at 1 500℃ in air for 2 h, the mass gain of sample is 2.21%. The oxidation behaviors of SiC, Si and B4C were also studied in the temperature range from 500℃ to 1 500℃, respectively, and the effective oxidation resistant temperature ranges of SiC, Si and B4C were explained. By analyses of oxidation kinetics, activation energies for the oxidation of SiC and Si are 196.7 kJ/mol and 167.3 kJ/mol, respectively. Because of the synergistic oxidation resistant mechanism of SiC, Si and B4C, the SiC/Si-B4C coating shows self-healing ability and excellent oxidation resistance in the temperature range from 600℃ to 1 500℃. 国家重点基础研究发展计划973计划项目（2015CB655202）