摘要
以不同用量的多官能巯基化合物与乙烯基硅氮烷预聚物组成液态光固化体系，经紫外光辐照后固化成聚合物陶瓷前驱体，后经1400℃无压热裂解制备氮化硅。采用热失重（TGA）分析陶瓷前驱体的热解特性，X射线衍射（XRD）分析热解后材料的相组成及晶态结构，场发射枪扫描电子显微镜（SEM）观察和表征材料的微观形貌。陶瓷前驱体在热解过程中分别在325—350℃和475—505℃出现两个失重峰，随着体系中巯基化合物含量的增加，前驱体的热解失重率增加，陶瓷收率降低，最终陶瓷的相对密度下降，结晶度增高，晶粒尺寸增大。经1400℃热解15h，得到部分α-Si3N4晶体；热解24h，得到大量α-Si3N4和少量β-Si3N4的材料，在空洞中发现富氮的细长纤状和片状晶体。
Silicon nitride ceramics were prepared by pyrolyzing the thiol-vinyl silizane polymer derived precurosors cured by UV. The pyrolysis behaviors of precurosors with different weight ratio of thiol to vinyl silizane were studied by TGA, and the ceramic phase com- positions and the microscopic structures of samples were characterized by XRD and SEM, respectively. The results showed that there were two peaks of rate of mass loss at 325 - 350℃ and 475 - 505℃ in DTA pattern, and the value of the peaks enhanced with increasing the amount of thiol compound. Moreover, the crystallinity, the size of grain increased and the relative density, the yield rate of the ceramic decreased with incorporating more thiol compound, α-Si3 N4 crystals were formed after pyrolysis under 1400℃ for 15h. α-Si3N4 could partially be converted into β-Si3N4 by prolonging pyrolysis time. The fiber-like and sheet crystals of nitrogen-rich SiN, were found in the holes of the microstructure.
出处
《航空材料学报》
EI
CAS
CSCD
2008年第6期88-92,共5页
Journal of Aeronautical Materials
基金
国家自然科学基金(20574056)
装备预研基金(9140A12070106HK0338)
西北工业大学博士论文创新基金(CX200614)
