凝胶浇注结合固相烧结制备具有多级孔结构的碳化硅陶瓷

Porous SiC Ceramics with Multiple Pore Structure Fabricated via Gelcasting and Solid State Sintering

以Isobam作为胶凝剂,聚甲基丙烯酸甲酯（PMMA）作为泡沫稳定剂和造孔剂,结合固相烧结制备出具有多级孔结构的碳化硅陶瓷,并研究了PMMA添加量、球磨机转速以及烧结温度对多孔陶瓷结构及性能的影响。结果表明：当球磨机转速为220 r/min、烧结温度为2100℃时,随着PMMA添加量由5wt%增加到20wt%,发泡过程受到抑制,但是泡沫的稳定性增强,所得多孔陶瓷的气孔率在51.5%~72.8%之间,压缩强度介于7.9~48.2 MPa之间;当PMMA加入量为20wt%时,随着球磨机转速由220 r/min增大到280 r/min,加剧了浆料的发泡过程,2100℃烧结所得多孔陶瓷的气孔率逐步增大,气孔孔径变大;当球磨机转速为220 r/min,PMMA加入量为20wt%时,随着烧结温度的升高,气孔率逐渐降低,力学性能有所提高。

Porous Si C ceramics with multiple pore structures were fabricated via gelcasting and solid state sintering. A novel gelling agent of Isobam was applied and PMMA was used as both foam stabilizer and pore forming agent. The mechanical properties of porous Si C ceramics were investigated as functions of PMMA content, rotating speed of ball mill, and sintering temperature. With PMMA content increasing from 5wt% to 20wt%, the foaming effect was inhibited while the stability of bubbles increased. When the rotating speed was 220 r/min, the open porosities of the as-prepared Si C ceramics sintered at 2100℃ varied from 51.5% to 72.8%, and compressive strength varied from 7.9 to 48.2 MPa. With the rotating speed increasing from 220 to 280 r/min, the foaming effect was aggravated and the porosities of Si C ceramics sintered at 2100℃ increased. While the sintering temperature increasing from 2050 to 2150℃, the Si C ceramics prepared with PMMA content of 20wt% at rotating speed of 220 r/min decreased in the open porosities while increased in compressive strength.