聚碳硅烷粘结法低温制备碳化硅多孔陶瓷

POROUS SILICON CARBIDE CERAMICS PREPARED BY POLYCARBOSILANE COAT-MIX METHOD

分别以平均粒径为10μm和20μm的两种规格碳化硅(SiC)粉末为原料、聚碳硅烷(PCS)为粘结剂,通过包混、过筛、模压成型、1000℃热解等工序制备了SiC多孔陶瓷,研究了PCS含量对SiC多孔陶瓷微观形貌、线收缩率、孔隙率与抗弯强度的影响,并对两种规格粉末制备的SiC多孔陶瓷性能进行了对比。结果表明:随着PCS含量的增加,两种规格粉末制备的SiC多孔陶瓷微观形貌都逐渐变得致密,当PCS含量为13%时,两种规格粉末制备的多孔陶瓷都出现了微观裂纹。随着PCS含量的增加,两种规格粉末制备的SiC多孔陶瓷孔隙率都逐渐降低,线收缩率都逐渐增大,抗弯强度先增大后降低,在PCS含量为10%时,平均粒径为10μm与20μm的SiC粉末制备的多孔陶瓷抗弯强度取得最大值,分别为31.6MPa与29.0MPa。

Using two kinds of silicon carbide（SiC） powder with average particle size of 10μm and 20μm as raw materials,Polycarbosilane（PCS） as binder.Porous SiC ceramics were prepared by processing of coat-mixing,sieving,molding and pyrolyzing at 1000℃.Effect of PCS content on the microstructure,linear shrinkage,porosity and flexural strength of porous SiC ceramics were studied.Properties of porous SiC ceramics prepared by two kinds of powder were compared.Results show that the microstructure of the SiC porous ceramics prepared by two kinds of powder gradually becomes dense with increasing the PCS content.When the PCS content is 13%,micro-cracks could be observed on porous ceramics.With increasing PCS content,the porosity gradually decreased,the linear shrinkage gradually increased,the flexural strength firstly increased and then decreased.When the PCS content is 10%,the flexural strength of porous SiC ceramics prepared by SiC powder with average particle size of 10μm and 20μm could be obtained the maximum were 31.6MPa and 29.0MPa,respectively.