Porous TiN ceramics with high porosity and uniform pore structure was prepared following the carbothermal reduction reaction between TiO2 and carbon. Influences of sintering additives and particle size of TiO2 on the microstructure and mechanical properties of porous TiN ceramics were investigated. Microstructure and mechanical properties of porous TiN ceramics were studied by XRD, SEM and three-point bending measurement. XRD analysis proved that the TiN phase has completely formed after reaction. In addition, SEM analysis showed that the resultant porous TiN ceramics were composed of fine grains with uniform pore structure. The addition of La2O3 not only accelerated the densification of porous TiN ceramics, but also decreased the porosity and increased the flexural strength. With a decrease in TiO2 particle size, the linear shrinkage increased and the porosity decreased accordingly.

The porous ceramic filter material is the most effective filter materials in the integrated gasification combined cycle. The porous silicon nitride due to its higher mechanical strength, as well as good corrosion resistance, is considered as a promising material in the integrated gasification combined cycle, and it were prepared directly though the SiO2 and α-Si3N4 through carbothermal reduction - pressureless sintering in nitrogen. There was a great lot weight loss in this reaction, so it was expected to create the high porosity materials. The rod-like β-Si3N4 grains and uniform pores were formed through changing the content of α-Si3N4, SiO2 and C. So high-performance and porosity controlled porous silicon nitride filter material was obtained. With an increasing in the α-Si3N4 content, the weight loss, the linear shrinkage, and the porosity decreased, the flexural strength increased accordingly. The porous silicon nitride filter material with addition of 50wt% α-Si3N4 showed a higher aspect ratio β-Si3N4 grains and better mechanical properties .