Preparation and Combustion Characteristics of Cordierite Coated SiC Reticulated Porous Ceramics

To solve the problems of thermal shock resistance and radiation efficiency attenuation due to the high-temperature oxidation of silicon carbide porous ceramics used in high-temperature combustion of porous media, a silicon carbide billet was prepared by an organic foam impregnation method. Also， porous silicon carbide ceramics containing cordierite infrared radiation coating were fabricated on the surface of silicon carbide skeleton via in-situ reaction sintering. The results show that the vacuum impregnation slurry can coat the skeleton surface and completely fill up the triangular holes of the silicon carbide skeleton. The three-layered porous silicon carbide ceramics with a cordierite coating, the central layer of the silicon carbide skeleton and the cordierite filling layer were prepared by sintering at 1350 ℃ . The mechanical properties, thermal shock resistance and high-temperature wet oxidation resistance of porous silicon carbide ceramics are improved due to the formation of the three-layered structure. The compressive strength of porous silicon carbide ceramics is 1.18 MPa after heat-treatment at 1350 ℃ , and the residual strength retention rate is 67%. According to the results of porous media combustion experiments, the three-layered structure of silicon carbide porous ceramic with a surface reinforcement by cordierite infrared radiation coating can reinforce silicon carbide porous media burner radiation heat transfer process and increase the combustion efficiency, thus increasing the burner surface temperature by 140 ℃ and reducing the emissions of CO and NO_x pollutants in the burner.