C/Si-C-N复合材料的制备及其氧化行为研究

采用CVI方法制备出了以Si-C-N陶瓷为基体以热解炭为界面的炭纤维增强陶瓷基复合材料(C/Si-C-N)。采用热重法研究了C/Si-C-N复合材料在空气中的氧化行为,并探讨了基体制备温度对复合材料抗氧化性能的影响。研究表明:不同温度下制备的复合材料,其氧化行为完全不同。高温下制备的C/Si-C-N复合材料其氧化失重随氧化温度的升高而持续增加;低温下制备的C/Si-C-N复合材料则其氧化失重先随温度的升高而增加,随后在800~1000℃之间随温度的升高而减小,接着又随温度的升高而增加。较高的制备温度可使复合材料在900℃以下温度区间的抗氧化性能得到提高,但却使900℃以上温度区间的抗氧化性能降低。

Fabrication and Oxidation Behavior of C/Si-C-N Composite

Carbon fiber reinforced Si-C-N matrix composite (C/Si-C-N) with a pyrolytic carbon (PyC) interlayer was fabricated by chemical vapor infiltration processing. The oxidation behavior of C/Si-C-N were investigated in air using thermogravimetry. The influence of the processing temperature on oxidation resistance of the C/Si-C-N composites was discussed. The results indicate that the C/Si-C-N composites prepared at different temperature have different oxidation behavior. The mass loss of C/Si-C-N prepared at higher temperature always increases with the increase of temperature. The mass loss of C/Si-C-N prepared at lower temperature firstly increases, then decreases between 800-1000℃, subsequently increases, with the increase of temperature. The higher processing temperature leads to the higher oxidation resistance of C/Si-C-N composites below 900℃, but make the oxidation resistance decrease above 900℃.