Abstract: SiC ceramic materials were prepared with Al powder as the sintering aid by pressureless sintering at 1600 ℃ for 3 h.The effects of particle size and content of Al powder on the structure and properties of SiC ceramic materialswere studied .The results show that Al powder can improve the sintering and mechanical properties of SiC ceramic materials , it also plays an important role in oxidation resistance , and the Al powder with smaller particle size has a significant effect on that of SiC ceramic materials.When theparticle size and content of Al powder are 48 μm and 4wt;, respectively, SiC ceramic materials can get the best performance .The bulk density and apparent porosity are 2.69 g/cm3 and 5.8;, thenthehardness and flexural strength are 2790 HV and 189 MPa, respectively.The excellent sintering and mechanical properties of SiC ceramic materials can be attributed to the sintering effect of Al powder and the strengthening effects of the in situ formed Al 2 O3 and mullite filling in SiC particles .

Key words: SiC ceramic materials were prepared with Al powder as the sintering aid by pressureless sintering at 1600 ℃ for 3 h.The effects of particle size and content of Al powder on the structure and properties of SiC ceramic materialswere studied .The results show that Al powder can improve the sintering and mechanical properties of SiC ceramic materials , it also plays an important role in oxidation resistance , and the Al powder with smaller particle size has a significant effect on that of SiC ceramic materials.When theparticle size and content of Al powder are 48 μm and 4wt;, respectively, SiC ceramic materials can get the best performance .The bulk density and apparent porosity are 2.69 g/cm3 and 5.8;, thenthehardness and flexural strength are 2790 HV and 189 MPa, respectively.The excellent sintering and mechanical properties of SiC ceramic materials can be attributed to the sintering effect of Al powder and the strengthening effects of the in situ formed Al 2 O3 and mullite filling in SiC particles .