Ablation resistance and mechanism of SiC/ZrC-ZrB2 double layer coating for C/C composites under plasma flame  

等离子火焰下C/C复合材料的SiC/ZrC-ZrB2双层涂层的耐烧蚀性能及其机理

作　　者：LIU Han-zhou YANG Xin FANG Cun-qian SHI An-hong CHEN Lei HUANG Qi-zhong 刘汉周;杨鑫;方存谦;石安红;陈蕾;黄启忠(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;Science and Technology of Advanced Functional Composite Laboratory,Aerospace Research Institute of Materials&Processing Technology,Beijing 100076,China)

机构地区：[1]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China [2]Science and Technology of Advanced Functional Composite Laboratory,Aerospace Research Institute of Materials&Processing Technology,Beijing 100076,China

出　　处：《Journal of Central South University》2020年第9期2538-2547,共10页中南大学学报（英文版）

基　　金：Project(51304249)supported by the National Natural Science Foundation of China;Project(14JJ3023)supported by the Science Foundation of Hunan Province,China。

摘　　要：To improve the ablation resistance of carbon/carbon(C/C)composites,a SiC/ZrC-ZrB2 double layer coating was fabricated by pack cementation and slurry-sintering method.The ablation resistance of the SiC/ZrC-ZrB2 coating was tested under plasma flame above 2300°C.The results indicate that the SiC/ZrC-ZrB2 double layer coating exhibits superior ablation resistance than the ZrC-ZrB2 single layer coating.After being ablated under the plasma flame for 20 s,the mass and linear ablation rates of the ZrC-ZrB2 coating are 0.89 mg/s and 15.3μm/s,while those for SiC/ZrC-ZrB2 coating are 0.09 mg/s and 24.15μm/s,respectively.During ablation,the SiC inner layer can generate SiO2 glass and result in the formation of ZrO2-SiO2 molten film.Compared with the ZrO2 molten film formed on the ZrC-ZrB2 coating surface,the ZrO2-SiO2 molten film with lower oxygen diffusion rate and viscosity enables the SiC/ZrC-ZrB2 coating to have better self-healing ability.Therefore,the enhanced ablation resistance of the SiC/ZrC-ZrB2 coating can be attributed to the formation of dense ZrO2-SiO2 molten film under the plasma flame.为了提高碳/碳(C/C)复合材料的耐烧蚀性能,采用包埋法和料浆刷涂法制备了SiC/ZrC-ZrB2双层涂层。在2300°C以上的等离子火焰下测试了SiC/ZrC-ZrB2涂层的耐烧蚀性能。结果表明,SiC/ZrC-ZrB2双层涂层的耐烧蚀性能优于ZrC-ZrB2单层涂层。等离子火焰烧蚀20 s后,ZrC-ZrB2涂层的质量烧蚀率和线烧蚀率分别为0.89 mg/s和15.3μm/s,而SiC/ZrC-ZrB2涂层的质量烧蚀率和线烧蚀率分别为0.09 mg/s和24.15μm/s,烧蚀过程中,SiC内层产生SiO2玻璃相,形成ZrO2-SiO2熔融膜。与ZrC-ZrB2涂层表面形成的ZrO2熔融膜相比,具有较低氧扩散速率和黏度的ZrO2-SiO2熔融膜使SiC/ZrC-ZrB2涂层具有较好的自愈性。因此,SiC/ZrC-ZrB2涂层耐烧蚀性能的提高可归因于等离子烧蚀过程中形成的致密的ZrO2-SiO2熔融膜。

关 键 词：ablation pack cementation SLURRY SiC/ZrC-ZrB2 coating 

分 类 号：TB332[一般工业技术—材料科学与工程] TB306