(中南大學 輕質高強結構材料國防科技重點實驗室，長沙 410083)
摘 要: 為了實現(xiàn)C/C復合材料氧化防護，對材料表面進行900 ℃、5 min的預氧化處理，然后應用包埋法在C/C復合材料表面制備SiC-ZrC-ZrB2涂層。研究預氧化處理對材料微觀結構、抗氧化性能和彎曲力學性能的影響。結果表明：預氧化試樣涂層與基體間形成嵌入式過渡層結構，材料抗氧化性能得到改善，經(jīng)1500 ℃靜態(tài)氧化4 h和8 h后，質量損失率分別為5.73%和10.88%。材料抗氧化性能提升的主要原因是界面的“釘扎效應”和過渡層減小涂層與基體間的熱應力。預氧化涂層試樣氧化前后彎曲性能增強，經(jīng)1500 ℃靜態(tài)氧化2 h和4 h后，強度保持率分別為104.86%和71.70%，均高于未預氧化涂層試樣的。氧化后材料內部結構受損更少以及陶瓷相的增韌作用是預氧化試樣彎曲力學性能提升的主要原因。
關鍵字: 預氧化處理；SiC-ZrC-ZrB2涂層；抗氧化性能；抗彎強度
（National Key Laboratory of Science and Technology for National Defence on High-strength Structural Materials, Central South University, Changsha 410083, China）
Abstract:In order to protect C/C composites from oxidation, the pre-oxidation treatment at 900 ℃ for 5 min was applied to the surface of material, and then, the SiC-ZrC-ZrB2 coating was prepared on the surface of C/C composites by pack cementation. The effects of pre-oxidation treatment on the microstructure, anti-oxidation properties and flexural mechanical properties of the materials were investigated. The results show that the inlaid transition layer is formed between the coating and substrate in the pre-oxidized sample. The oxidation resistance of the materials is improved, and the mass loss of the materials after 4 h and 8 h oxidation at 1500 ℃ are 5.73% and 10.88%, respectively. The main reason for the improvement of the oxidation resistance of the composites is that the pinning effect of the interface and the transition layer relieves the thermal stress between the coating and substrate. The flexural properties of the pre-oxidized sample are enhanced. After 2 h and 4 h oxidation at 1500 ℃, the flexural strength retentions of samples are 104.86% and 71.70%, respectively, which are higher than those without pre-oxidation. The internal structure of the composites after oxidation is less damaged and the toughening of ceramic phase is the main reason for the improvement of the flexural mechanical properties of the pre-oxidized sample.
Key words: pre-oxidation treatment; SiC-ZrC-ZrB2 coating; anti-oxidation property; bending strength
