Preparation and properties of spark plasma sintered magnesium aluminum oxynitride

In this paper, the effects of heating temperature and soaking time on the synthesis of magnesium aluminum oxynitride (MgAlON) by spark plasma sintering (SPS) were investigated. Results showed that the content of N decreased while that of O increased with the increasing of temperature, because of the reaction between Mg3N2 and H2O when the sample heated below 1500 degrees C. Owing to the rapid warming up rate and the reaction between graphite and H2O, the variation of chemical composition was lowered in the sample heated at higher temperature. During the heating process, shrinkage started above 1000 degrees C and expansion was observed above 1600 degrees C. Moreover, open pores were not detected in the sample heated at 1500 degrees C for 1 min and single phase MgAlON without pores could be obtained when heated at 1700 degrees C for 10 min. With the increasing of the content of Mg and the decreasing of N, all the thermal characteristics were increased and the cold bending strength was decreased, which may provide a standard data about the cold bending strength and the thermal characteristics of MgAlON with different composition.