多孔碳化硅复合陶瓷的制备与性能研究

Study on Synthesis and Properties of Porous SiC Composite Ceramics

以SiC粉和铝矾土为原料,石墨为造孔剂,通过干压成型,在空气气氛中烧结,制备了莫来石结合碳化硅多孔陶瓷。研究了其物相组成、微观结构、孔径分布、显气孔率和抗弯强度。结果表明:气孔主要来自于SiC颗粒的堆积间隙以及石墨的燃烧分解。在高温下,铝矾土与SiC氧化生成的SiO2原位反应,生成莫来石。石墨含量对多孔陶瓷的气孔率、抗弯强度以及孔径分布都有重要影响。石墨含量10 wt%,1400℃下烧结,保温3 h,制备的SiC多孔陶瓷的显气孔率为44.9%,抗弯强度高达41.0 MPa。

Mullite bonded SiC porous ceramics were fabricated through an in-situ reaction technology by using bauxite, SiC and graphite as raw materials. The green bodies were molded by pressing and sintered in air. The phase composition, microstructure, flexural strength, open porosity and pore size distribution were investigated. According to the results, the pores were produced by the stacking of SiC particles and burning out of graphite. Under high temperature, SiO2 obtained by the oxide of SiC could reaction with bauxite to form mullite. Graphite content has great impact on the flexural strength, open porosity and pore size distribution of the porous ceramics. The samples with 10wt% graphite content sintered at 1400 ℃ for 3 h have an open porosity 44.9% and flexural strength 41.0 MPa.