2Si-B-3C-N陶瓷的热压烧结工艺

In the current research, nano 2Si-B-3C-N ceramics were prepared by the hot pressing technique. Employing the methods of XRD, SEM and TEM, careful investigation was carried out on the effect of hot pressing parameters on the microstructure and properties of the prepared ceramics. Results show that, the sintering temperature and pressure has important influence on the structure and properties of the 2Si-B-3C-N ceramic, while the holding time and gas pressure has little effect. When the temperature, pressure, holding time and gas pressure are designed as 1 900℃and 80 MPa,respectively, the prepared ceramic has larger density and mechanical properties. And the relative density, bending strength, elastic modulus, fracture toughness and Vickers hardness of the prepared ceramic is about 88.7%, 331.1 MPa, 139.4 GPa, 2.8 MPa•m^1/2 and 5.7 GPa, respectively. While the temperature is decreased to 1 800℃ or the pressure is reduced to 50 MPa, the density and mechanical properties of the prepared ceramic are significantly decreased. The elevated temperature and pressure will facilitate the deformation, sliding and rearrangement of the ceramic particles, as well as accelerate the atomic diffusion, and hence promote the sintering and property improvement of the ceramic.