Flash sintering of AlN ceramics with Y₂O₃ additive

This study demonstrates the fabrication of dense AlN-based ceramics through the flash sintering technique for the first time. Flash sintering was performed at a furnace temperature of 1500 °C with 10 wt% Y₂O₃ as a sintering aid in a nitrogen atmosphere. The effects of the current density and holding time on the microstructure evolution and mechanical properties were investigated. The results show that the relative density, grain size, and Vickers hardness of specimens increase with increasing current density and holding time. The specimen showed the highest relative density of 98.6 % and a Vickers hardness of 12.68 GPa when a current density of 100 mA/mm² and a holding time of 60 min were used. Additionally, the grain sizes at the positive side of the electrodes were found to be larger than those at the negative side. These findings suggest that dense AlN-based ceramics can be fabricated in a rapid and efficient way through the flash sintering technique.