C／C 复合材料 ZrB2-SiC 基陶瓷涂层制备及烧蚀性能研究

摘要

To improve the ablation resistance, ZrB2-SiC coatings were prepared by two-step slurry painting on C/C com-posites.The ZrB2-SiC-ZrC transition layer was prepared by reactive sintering, then ZrB2-20%SiC-5%Si3N4、 ZrB2-15%SiC-20%MoSi2、 ZrB2-15%SiC-20%TaC outer coatings were prepared on it .The ablation test was conducted under oxy-acetylene torch at 2 500 ℃ for 60s.X-ray diffractometry and scan electron microscopy were employed to investigate the microstructure and ablation mechanism .The results show that the transition layer has a good combination with the matrix , and no obvious lamination appeared when connected to the outer layer.Owing to the effect of Si3N4 and MoSi2 as sintering aids, the structure of ZrB2-20%SiC-5%Si3 N4 and ZrB2-15%SiC-20%MoSi2 outer coating is quite dense.Coating ZSS and ZSM showed better ablation resistance .The linear ablative rate and mass ablative rate of coating ZSS and ZSM were 0.075 mm/s, 0.0081g/s and 0.018 mm/s, 0.0064g/s respectively.The coating ZST does not show effective oxidation protection because of its loose structure , and it caused the burning through of the coating .%为提高C/C复合材料的抗烧蚀性能，采用两步刷涂-烧结法制备了 ZrB2-SiC 基陶瓷涂层。首先利用反应烧结制备ZrB2-SiC-ZrC过渡层，并在此基础上制备了ZrB2-20％SiC-5％Si3 N4、 ZrB2-15％SiC-20％MoSi2、 ZrB2-15％SiC-20％TaC 3种外涂层。利用 XRD和扫描电镜研究了涂层的相组成和显微形貌，并采用氧乙炔焰烧蚀仪测试了涂层在2500℃、60 s的抗烧蚀性能，探讨了涂层的高温烧蚀机理。结果表明：利用反应烧结制备的过渡层与基体结合紧密，且与外涂层无明显分层现象，起到了良好的过渡作用；由于 Si3 N4及 MoSi2起到了烧结助剂作用，使 ZrB2-20％SiC-5％Si3 N4、 ZrB2-15％SiC-20％MoSi2外涂层结构较为致密； ZrB2-20％SiC-5％Si3 N4、 ZrB2-15％SiC-20％MoSi2涂层表现出了较好的抗烧蚀性能，其中 ZrB2-20％SiC -5％Si3 N4涂层线烧蚀率及质量烧蚀率分别为0.075 mm/s、0.0081 g/s， ZrB2-15％SiC-20％MoSi2涂层线烧蚀率及质量烧蚀率分别为0.018 mm/s、0.0064 g/s，而ZrB2-15％SiC-20％TaC涂层由于结构较为松散，未能起到有效的氧化防护，导致涂层被烧穿。