Effect of V2O5 addition on the properties of reaction-bonded porous SiC ceramics

Mullite-bonded porous SiC ceramics were prepared with and without V2O5 addition in air by an in situ reaction bonding technique. This process is based on the oxidation of SiC and the mullitization between oxidation-derived SiO2 and Al2O3. The effects of V2O5 addition on the phase composition, microstructure, open porosity, flexural strength and pore size distribution of porous SiC ceramics were investigated. With the addition of V2O5, the mechanical properties of porous SiC ceramics were improved. It was found that the V2O5 addition strongly promoted the phase transformation towards mullite and reduced the temperature of mullitization by nearly 400 °C. When 4 wt% V2O5 was added, a high strength of 30.11 MPa was achieved at an open porosity of 42.1%.