Preparation and Properties of Porous SiC Ceramics by Adding Micro SiC and Al2O3 Powders
A reaction bonding technique and a method of layer coating were developed to fabricate in-situ mullite-bonded porous silicon carbide(SiC)ceramics.The green body was formed by press molding using 300-400μm SiC as raw material,micro SiC and α-Al2O3 powders as bonding agent(mass ratio of 1:2.5),65μm graphite as pore-forming agent and polyvinyl alcohol(PVA)as binder,respectively.The micro powders are coated on the surface of coarse SiC particles.After sintering,micro-SiC particles were oxidized to silica(SiO2)then transforming into cristobalite,which finally reacted with α-Al2O3 to produce mullite(3Al2O3·2SiO2).The results show that SiC particles are bonded by the mullite and oxidation-derived SiO2.The open porosity of the samples decreases from 31.30%to 20.50%with the amount of micro powders increasing from 5%to 20%.The bending strength increases at the first stage and then decreases with the increase of micro powders,and the samples with 10%mass of fine powders shows relatively high flexural strength of up to 23.51 MPa.
porous SiC ceramics powders reaction bonded mullite bonding porosity
Liu Jiadong Peng Zhijian Liu Qingzhu Si Kaikai Sun Guangchao Liu Kaiqi
School of Engineering and Technology,China University of Geosciences,Beijing 100083,China;State Key School of Engineering and Technology,China University of Geosciences,Beijing 100083,China State Key Laboratory of Multi-phase Complex Systems,Institute of Process Engineering,Chinese Academy
国际会议
北京
英文
1227-1234
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）