Abstract

This article presents the challenges toward the successful consolidation of Al_2O_3 nanopowder using magnetic pulsed compaction (MPC). In this research the ultrafine-structured Al_2O_3 bulks have been fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their properties were investigated. The obtained density of Al_2O_3 bulk prepared by the combined processes was increased with increasing MPC pressure from 0.5 to 1.25 GPa. Relatively higher hardness and fracture toughness in the MPCed specimen at 1.25 GPa were attributed to the retention of the nanostructure in the consolidated bulk without cracks. The higher fracture toughness could be attributed to the crack deflection by homogeneous distribution and the retention of nanostructure, regardless of the presence of porosities. In addition, the as consolidated Al_2O_3 bulk using magnetic pulsed compaction showed enhanced breakdown voltage.

• Keywords: alpha-alumina;Magnetic pulsed compaction (MPC);Densification;Breakdown voltage;