Abstract: High strength silicon carbide foam ceramics were fabricated at 950 ℃ by polymer sponge replicas method with aluminum dihydrogen phosphate as blinder.The effect of SiC contents and aluminum dihydrogen phosphate on microstructure and properties of the silicon carbide foam ceramics were investigated.The results show that the SiC particles were bonded by A-Al(PO3)3.The open cell porosity structure of silicon carbide foam ceramics was well-formed, the open porosity was from 75; to 91;.As the aluminum dihydrogen phosphate content increases, the linear shrinkage, volume density and flexural strength gradually increases, while the open porosity decreases.As the solid content increase, the linear shrinkage and open porosity declines, while the volume density and flexural strength gradually climbes.In particular, the flexural strength of silicon carbide foam ceramics is (2.22±0.26) MPa when the aluminum dihydrogen phosphate and SiC contents were 40; and 60;, respectively.

Key words: High strength silicon carbide foam ceramics were fabricated at 950 ℃ by polymer sponge replicas method with aluminum dihydrogen phosphate as blinder.The effect of SiC contents and aluminum dihydrogen phosphate on microstructure and properties of the silicon carbide foam ceramics were investigated.The results show that the SiC particles were bonded by A-Al(PO3)3.The open cell porosity structure of silicon carbide foam ceramics was well-formed, the open porosity was from 75; to 91;.As the aluminum dihydrogen phosphate content increases, the linear shrinkage, volume density and flexural strength gradually increases, while the open porosity decreases.As the solid content increase, the linear shrinkage and open porosity declines, while the volume density and flexural strength gradually climbes.In particular, the flexural strength of silicon carbide foam ceramics is (2.22±0.26) MPa when the aluminum dihydrogen phosphate and SiC contents were 40; and 60;, respectively.