摘要
采用两步包埋法及料浆涂刷-烧结法在二维碳布叠层碳/碳复合材料表面依次制备了SiC/MoSi2-Si-Cr-B包埋涂层及磷酸盐玻璃外涂层,研究了其在950℃静态空气环境中自由状态的抗热震、防氧化性能及不同弯曲变形状态下的防氧化性能,并借助X射线衍射分析仪及扫描电子显微镜对涂层试样的组成成分及微观组织形貌进行了分析。结果表明:950℃自由状态下该涂层体系的氧化失重率为负值,抗热震、防氧化效果良好;磷酸盐玻璃层在950℃软化熔融呈粘流态,可填补涂层内的裂纹和孔洞,阻止氧的入侵,有效提高了涂层整体的抗热震及抗氧化性能;但弯曲变形状态下,涂层试样的氧化失重率随形变量的增加而提高,形变会在一定程度上降低碳/碳复合材料抗氧化涂层的保护效果,加速材料的氧化失效。
The compound coating composed of SiC/MoSi2-Si-Cr-B layer and phosphate glass outer layer was prepared on the surface of 2D carbon cloth laminated carbon/carbon composites by two-step pack cementation and slurry-sintering tech- niques. At 950℃, the anti-oxidation performance of coated samples was evaluated in free-state and states with different deformations, respectively. In addition, thermal shock test was also conducted from 950℃ to room temperature. The phase composition and microstructure of the as-prepared coating were characterized by XRD and SEM. The results show that the coating exhibits favorable thermal shock resistance and anti-oxidation properties, with a negative weight loss rate at 950℃. The phosphate glass will be melted into a viscous-flow state at 950℃. It could seal the cracks and holes, resul- ting in the improvement of the thermal shock and oxidation resistance of the compound coating. However, under the ben- ding state, the oxidation weight loss rate increases with the increase of deformation. The deformation will reduce the pro- tective effect of anti-oxidation coating to some extent, accelerating the oxidation failure of carbon/carbon composites.
出处
《中国材料进展》
CAS
CSCD
2013年第6期375-379,共5页
Materials China
基金
国家自然科学基金(51072166
51221001)
