含先驱体聚合物浆料浇注成型制备SiC多孔陶瓷

Fabrication of Porous SiC Ceramics by Precursor Polymer-contained Slurry Slip Casting Method

采用SiC粉体与聚碳硅烷(PCS)为原料浇注成型低温烧结制备SiC多孔陶瓷,研究了PCS含量对SiC多孔陶瓷性能的影响。结果表明,PCS含量大于2wt%时可浇注成型,PCS经烧结后生成裂解产物将SiC颗粒粘结起来。所得SiC多孔陶瓷孔径呈单峰分布、孔径分布窄、热膨胀系数低、烧结过程中线收缩率小。随着PCS含量的增大烧成SiC多孔陶瓷的孔隙率降低,但强度显著提高。PCS含量为6wt%时多孔陶瓷的孔隙率、弯折强度和线收缩率分别为36.2%、33.8MPa和0.42%。

SiC micropowder and polycarbosilane （PCS） were adopted as the starting materials, shaped by the slip casting method and then sintered at low temperature to obtain porous SiC ceramics. Effect of PCS content on the properties of porous SiC ceramics was studied, Results show that the slurry can be shaped when the PCS content is over 2wt% and the SiC particles are bonded by PCS pyrolysis products. The as-fabricated porous SiC ceramics exhibit a unimodal and narrow pore size distribution, high fracture strength, low coefficient of thermal expansion, and small linear shrinkage of bodies during the sintering process. With the increase of PCS content, the porosity of the porous ceramics decreases, but the fracture strength increases remarkably. The porosity, fracture strength and linear shrinkage of porous SiC ceramics are 36.20% ,aa. 8MPa and 0. 42% respectively when PCS content is 6wt%.