射频直热法在碳纤维表面低温涂覆SiC涂层研究

SiC Coating on Surface of Carbon Fibers at Low Temperature by Radio-frequency Direct-heating Method

采用新型工艺射频直热法在碳纤维表面低温化学气相沉积SiC涂层,以达到节能、控制涂层厚度和降低成本的工业生产要求.利用XRD,EPMA,TEM研究了工艺与涂层结构关系、涂层的微观结构、拉伸和抗氧化性能.结果表明:SiC涂层在700～780℃发生结晶,提高温度或者减慢走丝速度,结晶更完善;低温沉积涂覆后纤维的拉伸性能基本不下降,低温抗氧化性能有所提高;样品的高温抗氧化性能并不理想,有待于进一步的工艺探索.

A new technology of radio-frequency （RF） direct-heating method was used to fabricate silicon carbide （SIC） coatings on the surface of carbon fibers （CF） at low temperature by chemical vapor deposition （CVD） in order to satisfy the industry production requirements for energy conservation, high thermal efficiency, Controllability of coating thickness and low cost. The correlation between technical parameters and coating structure, the microstructure of coatings, tensile strength and anti-oxidation performance was studied by XRD, EPMA and TEM. The results showed thatthe SiC coatings crystallized at 700-800℃ during deposition and the degree of crystallization improved with increasing temperature or decreasing running rate of the fibers. The tensile strength only had a slight drop and the anti-oxidation of CF was improved when the coatings were heated at low temperature. But a poor anti-oxidation happened when the coating was heated to high temperature. Technical parameters must he adjusted to obtain desired tensile strength and oxidation resistance performance.