WANG Zicheng 1, RUAN Wanxing 1, GUO Xingzhong 1, YANG Hui 1, YANG Xinling 2, ZHENG Pu 2, GAO Lihua 2
(1. School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China; 2. Dongxin Seals Co., Ltd., Taizhou 317015, Zhejiang, China)
Abstract: Silicon carbide/graphite composite ceramic was prepared by liquid silicon infiltration processing using pure carbon powder as raw material, phenolic resin as binder, and polyvinyl alcohol as pore forming agent. The influence of polyvinyl alcohol (PVA) content on the sintering behavior and the microstructure of the ceramic was investigated. The results show that PVA volatilized during the sintering and generated the porous structures in the body, which was beneficial to the permeation of liquid silicon and the reaction between silicon and carbon powders to form the SiC/C composite ceramics. The sintering and mechanical properties of the SiC/C composite ceramic improved with the increase of PVA content. When 15% PVA was added, the properties of the SiC/C composite ceramics were the best. Whereas,the content of PVA did not affect the phase composition of the SiC/C composite ceramic. The resultant silicon carbide/graphite composite ceramic could be applied in the field of mechanical seals.
Key words: silicon carbide ceramics; carbon powder; reactive sintering; permeation