In-situ synthesis and properties of cordierite-bonded porous SiC membrane supports using diatomite as silicon source

Cordierite-bonded porous SiC membrane supports with diatomite as silicon source were prepared in air at 1150-1400 °C via reaction bonding technique. The phase composition, microstructure, flexural strength, open porosity, pore size distribution as well as dielectric properties of membrane supports were investigated as a function of the mass ratio of different starting materials, sintering temperature, graphite content and holding time. It was found that the diatomite addition strongly promoted the phase transformation towards cordierite, meanwhile, due to the enhancement of necks at the contacting pionts growth by the additions of diatomite (5.17 wt%), a high three-point flexural strength of 49.19 MPa was achieved at an open porosity of 37.72% sintered at 1250 °C for 3 h. Meanwhile, the cordierite structure can incorporate of diatomite (like Fe2O3) by solid solution formation, which can highly enhance on the electrical properties of cordierite-bonded SiC porous ceramics.