论文部分内容阅读
为揭示具有良好高温(1300～1600℃)抗氧化性能的SiC-Glass涂层在中低温(500～1200℃)条件下的氧化防护性能,对SiC-Glass涂层碳/碳(C/C)复合材料的中低温氧化行为和机制进行了系统研究。结果表明,SiC-Glass涂层C/C复合材料的中低温氧化失重服从直线规律,但氧化机制存在温度依赖性,可分为2个区段:(1)低温区(500～800℃),氧化失重速率与温度服从Arrhenius关系,氧化主要受控于氧在涂层缺陷内的扩散速率;(2)在中温区(800～1200℃),氧化失重速率与温度不服从Arrhenius关系,氧化过程受氧在涂层缺陷中的扩散、SiC内涂层材料的氧化、Glass外涂层的部分熔融愈合等多种因素联合控制。对比分析表明,SiC-Glass涂层的中低温抗氧化性能不及其高温抗氧化性能优异。中低温下,涂层缺陷愈合不充分是导致这一现象的主要原因。
In order to reveal the oxidation protective properties of SiC-Glass coatings with high temperature (1300-1600 ℃) oxidation resistance at low and medium temperature (500-1200 ℃), the SiC / Glass coated carbon / carbon (C / C) The low temperature oxidation behavior and mechanism of the composites were studied systematically. The results show that the low and middle temperature oxidation weight loss of SiC-Glass coated C / C composites obeys the linear rule, but the oxidation mechanism is temperature dependent and can be divided into two sections: (1) low temperature (500 ~ 800 ℃) The rate of oxidation and weight loss follows the Arrhenius relation with temperature, and the oxidation is mainly controlled by the diffusion rate of oxygen in the coating. (2) In the medium temperature range (800-1200 ℃), the rate of oxidation and weight loss does not obey the Arrhenius relation with the temperature. Diffusion of oxygen in the coating defects, oxidation of the SiC inner coating material, partial melting healing of the outer glass coating and the like. The comparative analysis shows that the low-temperature oxidation resistance of SiC-Glass coating is not as good as its high temperature oxidation resistance. Under low temperature, inadequate healing of coating defects is the main reason for this phenomenon.