3D-C_f/SiC复合材料抗高温氧化涂层结构设计与自愈合机理

Structure design and self-sealing mechanism of anti-high temperature oxidation coatings of 3D-C_f/SiC composites

为了提高3D-Cf/SiC复合材料耐高温氧化性能,采用CVD和粉末烧结技术相结合依次在其表面制成CVD-SiC粘接层—自愈合功能层—CVD-SiC耐冲蚀层等抗高温氧化涂层。运用TG、SEM和TEM等手段研究了自愈合机理。结果表明,抗高温氧化涂层自愈合机理主要是B4C和MoSi2等氧化增重形成在高温下可流动的玻璃相,玻璃相充填材料裂纹和空隙有效地阻碍氧气渗透。因而3D-Cf/SiC复合材料具有较好的耐高温氧化性能。

In order to increase anti-high temperature oxidation properties of 3D-Cf/SiC composites,oxidation resistant coatings,including a chemical vapor deposition （CVD）SiC bonding layer,a self-sealing active layer and a CVD-SiC erosion resistant layer,were prepared on carbon fiber reinforced silicon carbide （3D-Cf/SiC）com-posites by CVD and powder sintering technology.TG,SEM and TEM were used to research self-sealing mechanism of the coating.The results show that the self-healing mechanism of the coating was mainly that flowing glass phases oxidized of B4 C and MoSi2 fill in material cracks and pores,and block off the passage of oxygen at high temperature.So 3D-Cf/SiC composites have good high temperature oxidation resistance properties.