LAUSR

Abstract An efficient and flexible chemical co-precipitation method has been used to synthesize nanoscale Al 2 O 3 -GdAlO 3 powders with eutectic composition. The as-synthesized powders exhibit a highly dispersive and homogeneous distribution with an average particle size of 50 nm. The phase transition in the resulting powders strongly depends upon the calcination temperature. GdAlO 3 undergoes complete crystallization after calcination at 1050 °C, however, the diffraction peaks of α-Al 2 O 3 are found at a relatively high calcination temperature of at least 1300 °C. The fully-densified Al 2 O 3 -GdAlO 3 ceramic with eutectic composition obtained by hot pressing the nanoscale powders at 1500 °C exhibits a room temperature flexural strength of 556 MPa, a Vickers hardness of 17.3 GPa and a fracture toughness of 7.5 MPa m 1/2 . The high temperature flexural strength of the as-sintered Al 2 O 3 -GdAlO 3 ceramic is measured to be 515 MPa after bending tests at 1000 °C.