Effect of nano-AlN content on the microstructure and mechanical properties of SiC foam prepared by siliconization of carbon foam

Mesophase pitch (MP) was doped by nano-AlN to produce carbon foams followed by liquid silicon infiltration to prepare silicon carbide foams. Experiments have been carried out to investigate the effects of nano-AlN doping on bending strength and thermal shock resistance of the silicon carbide foams. Microstructure observation and phase identification indicate that AlN doping strengthens the silicon carbide foams by grain refining and solid-solution reaction. With 13 wt.% of nano-AlN, silicon carbide foams were obtained with the highest quality in bending strength of 14.1 MPa, thermal shock resistance, and bulk density of 0.73 g/cm3.