Effect of nanometer Al2O3 powder on microstructure and properties of alumina ceramics by microwave sintering

The effect of nanometer Al2O3 powder on microstructure and properties of alumina ceramics by microwave sintering was investigated. The maximum bending strength and fracture toughness of alumina ceramics reach up to 294.41 Mpa and 4.14 Mpa m1/2, as the alumina ceramics with 20 wt% nanometer A12O3 powder was microwave sintered at 1500 °C for 30 min. It may be attributed to the addition of nanometer A12O3 powder and microwave-sintering process resulting in a synergistic effect on improvement of microstructure and mechanical properties.

► High quality alumina ceramics were fabricated by microwave sintering using nanometer and coarse grain Al2O3 as raw materials.
► Nanometer Al2O3 powder addition can improve the sinterability and mechanical properties of the alumina ceramics.
► This kind of performance improvement can be obtained only when the content of nanometer Al2O3 is in a certain amount.
► The maximum mechanical properties of microwave sintered alumina ceramics can be obtained up to 294.41 Mpa and 4.14 Mpa m1/2.
► Nanometer Al2O3 powder and microwave sintering process resulted in a synergistic effect on its microstructure and mechanical properties.