研究了有涂层与无涂层的碳／碳复合材料的高温氧化行为。等离子喷涂的陶瓷涂层，在氧化温度不大于１０００℃条件下，对碳／碳复合材料有良好的保护作用，无涂层的碳／碳复合材料在６００～９００℃温度范围内的氧化机制相同；而有涂层时，氧化机制在７６０℃左右发生变化．碳毡增强碳基复合材料的氧化从表面碳毡开始，碳毡的氧化速率较基体碳的氧化速率大．
A ceramic coating consisting of ZrO2, Y2O3, SiO2 and B2O3 was prepared using plasma spraying onthe surface of carbon felt/carbon comosites. The coating remarkably improved the oxidation resistanceof the composite below 1000℃ in air. Careful observation of the microstructure of the composite afteroxidation revealed that oxidation started from carbon felt on surface and that the carbon felt was oxidized more rapidly than the carbon matrix. The relationship between in K and 1/T on Arrhenius plot wasexamined. The linear dependence from 600℃ to 900℃ for the uncoated specimens indicated that theoxidation process was governed by single mechanism. For the coated specimens the flection at 760℃InK ~1/T plot suggested a change of oxidation mechanism. Thus two dufferent activation energy valuescould be evaluated.A model that explains the oxidation behaviour of the coated carbon/carbon compositeis proposed.
参考文献
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