Si3N4-MgO-CeO2陶瓷烧结过程中的致密化与相变

Silicon nitride ceramics show greatpotential for wide applications. It is difficult to densify silicon nitride due to itscovalent nature of bonding. A new sintering aid with combination of MgO and CeO₂was used in the present study. The effects of MgO-CeO₂ on densification andphase transformation during sintering of Si₃N₄ were discussed. ForSi₃N₄-MgO-CeO₂ ceramics，a lot of liquid phase existedat 1450℃，and densification process took place rapidly from 1550℃ to 150℃；thephase transformation from α-Si₃N₄ to β-Si₃N₄took place rapidly from 1550℃ to 1660℃，the phase transformation process lags behindthe densification process. The nonpressure sintered Si₃N₄-MgO-CeO₂ceramics achieved a bending strength of 948MPa. MgO-CeO₂ can be considered asan effective sintering aid for Si₃N₄.