CHEN Yang, HOU Yongzhao, FU Jie, ZHONG Cheng, ZHU Nannan, XUE Jing, WEN Guangwu
(School of Materials Science and Engineering, Shandong University of Technology, Zibo 255000, Shandong, China)
Abstract: SiO2 ceramic matrix composites (SiO2f/SiO2) were prepared through impregnation and cracking of silica sol as impregnation solution, with BN nano powder, polyimide (PI) and self-made polysiloxane (PSO) and quartz fiber as reinforcement agent. Pull-out behavior of the fibers with different interface protections was studied, while microstructure and mechanical properties of the composites were evaluated. It is found that PSO had good fluidity and infiltration effect (with a contact angle of < 30°). After curing at 90 ℃, the formation of amorphous SiO2 can be completed at above 600 ℃, with a ceramic yield of 83%. The presence of PI effectively enhanced the interface packaging, resulting in desired interface bonding strength. After six cycles of PSO impregnation-cracking, density of the SiO2f/SiO2 composite reaches 1.75 g·cm−3, with bending strength and elastic modulus at room temperature to be (61 ± 8) MPa and 7.1 GPa, respectively. The fibers are well protected by the matrix interface and there is obvious fiber pull-out.
Key words: SiO2f/SiO2 ; impregnation-cracking; polysiloxane; mechanical property