Influence of TiO2 addition on phase composition and properties of porous SiC ceramics
To achieve high porosity and strength,porous SiC ceramics were fabricated by utilizing α-SiC powder,Si powder and TiO2 powder as starting materials and firing at 1 400 ℃ for 3 h in an argon atmos-phere.The influence of the TiO2 addition(0,2％,4％and 8％,by mass)on the phase composition,micro-morphology,pore size distribution and main physical properties of the materials was studied.The results show that as the TiO2 addition increases,the diffraction peak of Si gradually diminishes,while Ti3O5 and TiSi2 are detected in the materials.With the formation of these new phases,SiC particles are bonded more tightly,resulting in reduced apparent porosity and average pore size along with significantly improved me-chanical properties.When the TiO2 addition is 8％,exceptional comprehensive properties of the material are achieved in terms of the apparent porosity of 33.6％,cold modulus of rupture of 29.6 MPa and average pore size of 0.27 μm.
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