(中南大学 轻质高强结构材料国防科技重点实验室，长沙 410083)
摘 要: 为了实现C/C复合材料氧化防护，对材料表面进行900 ℃、5 min的预氧化处理，然后应用包埋法在C/C复合材料表面制备SiC-ZrC-ZrB2涂层。研究预氧化处理对材料微观结构、抗氧化性能和弯曲力学性能的影响。结果表明：预氧化试样涂层与基体间形成嵌入式过渡层结构，材料抗氧化性能得到改善，经1500 ℃静态氧化4 h和8 h后，质量损失率分别为5.73%和10.88%。材料抗氧化性能提升的主要原因是界面的“钉扎效应”和过渡层减小涂层与基体间的热应力。预氧化涂层试样氧化前后弯曲性能增强，经1500 ℃静态氧化2 h和4 h后，强度保持率分别为104.86%和71.70%，均高于未预氧化涂层试样的。氧化后材料内部结构受损更少以及陶瓷相的增韧作用是预氧化试样弯曲力学性能提升的主要原因。
关键字: 预氧化处理；SiC-ZrC-ZrB2涂层；抗氧化性能；抗弯强度
（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
