先驱体转化制备ZrO_2改性SiC陶瓷的氧化行为研究

Oxidation Behavior of ZrO_2-doped Silicon Carbide Ceramics by Precursor Infiltration Pyrolysis Technique

采用先驱体转化法,以聚碳硅烷、二乙烯基苯和正丁醇锆为原料高温裂解制备了ZrO2改性的SiC陶瓷材料,结合XRD,SEM和EDS能谱等测试方法,研究ZrO2的添加对材料氧化行为的影响。结果表明:ZrO2引入后,SiC陶瓷材料在1600℃开始氧化,表面生成了SiO2阻氧层阻止气体逸出,宏观上形成气泡,到1700℃材料氧化较严重,表面变得凹凸不平,出现较多空洞,并且存在一定程度的失重;1700℃氧化后,含ZrO2的材料表面和内部均有一定程度的氧化,表面的主要成分为SiO2,内部有部分SiC发生了氧化,两种材料氧化层呈梯度分布;在高温氧化过程中,ZrO2会发生由四方相向单斜相的相变,SiC对ZrO2的相变具有抑制作用,而材料氧化后生成的SiO2则无法抑制ZrO2的相变。

ZrO2 modified silicon carbide（SiC） ceramics was fabricated with polycarbosilane, divinyl- benzene and zirconium n-butoxide by precursor infiltration pyrolysis technique, and oxidation behavior was investigated by means of XRD, SEM and EDS. The results showed that after impregnation of ZrO2, the SiC ceramics began to be oxided at 1600°C, and bubbles appeared on the surface because of SiO2oxidation resistant layer formed. When oxided at 1700°C, the ceramics showed severe oxidation, with serval pit at the surface and a certain mass loss; both of the surface and inner of the ceramics were oxided after oxidation at 1700°C ,and the mostly component of the surface was SiO2 ,meanwhile, SiC in the inner was partly oxided to SiO2, both of the oxidation layers of the two ceramics were gradient; The transformation from the tetragonal phase to the monoclinie phase of ZrO2 happened at high temperature during oxidation, the existence of SiC can prevent this phase transformation while SiO2 can＇t.