Damage behavior of atomic oxygen on CVD SiC coating-modified carbon/carbon composite in low earth orbit environment  

作　　者：Guanghai Liu Laifei Cheng Xingang Luan Jiaxin Zhang 

机构地区：[1]Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University

出　　处：《Journal of Materials Science & Technology》2019年第12期2957-2965,共9页材料科学技术（英文版）

基　　金：funded by the National Natural Science Foundation of China (Nos. 51632007 and No. 51672218 and No. 51821091);the National Key R&D Program of China (Grant No.2017YFB1103500)

摘　　要：In this work, samples of carbon/carbon(C/C) and chemical vapor deposited(CVD) SiC-coated C/C samples were investigated to understand the AO damage mechanism in low Earth orbit(LEO) environment. The ground-based simulated atomic oxygen(AO) generator was employed. Results indicate that the CVD SiC coating exhibited improved radiation resistance properties against AO radiation as evidenced by a 16%better strength retention ratio, 60% less mass ablation, and increased strength stability. The magnitude of these influences affected the surface morphology, as observed by scanning electron microscopy(SEM)and surface resistance meter test results. The variations in the surface constituents were confirmed by X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) results. The main products left on surface after AO exposure are SiO2 and SiCxOyfilm. Additionally, Si atoms are found to be the preferential reacting element in the SiC coating, and this process is accompanied by graphite precipitation, grain growth, and crack necking. Also, the damage mechanism of the AO-exposed SiC coating was revealed and is discussed.In this work, samples of carbon/carbon(C/C) and chemical vapor deposited(CVD) SiC-coated C/C samples were investigated to understand the AO damage mechanism in low Earth orbit(LEO) environment. The ground-based simulated atomic oxygen(AO) generator was employed. Results indicate that the CVD SiC coating exhibited improved radiation resistance properties against AO radiation as evidenced by a 16%better strength retention ratio, 60% less mass ablation, and increased strength stability. The magnitude of these influences affected the surface morphology, as observed by scanning electron microscopy(SEM)and surface resistance meter test results. The variations in the surface constituents were confirmed by X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) results. The main products left on surface after AO exposure are Si O2 and SiCxOyfilm. Additionally, Si atoms are found to be the preferential reacting element in the SiC coating, and this process is accompanied by graphite precipitation, grain growth, and crack necking. Also, the damage mechanism of the AO-exposed SiC coating was revealed and is discussed.

关 键 词：CARBON/CARBON CVD SiC coating Low earth orbit Atomic oxygen EXPOSURE STRESS 

分 类 号：TB332[一般工业技术—材料科学与工程] TB306