Investigation on mechanical properties of AlON ceramics synthesized by spark plasma sintering

AlON ceramics were prepared by spark plasma sintering (SPS) with raw materials (60 mol% Al₂O₃ and 40 mol% AlN) and sintering aids (0.16 wt% Y₂O₃ + 0.3 wt% MgO + 0.06 wt% La₂O₃). The effects of the SPS parameters on the microstructures and mechanical properties of the SPSed AlON ceramics were investigated systematically. This investigation suggested that when the sintering temperature was 1580 ℃, the sintering pressure was 50 MPa, and the holding time was 5 min, the AlON ceramics with excellent mechanical and optical performances were successfully synthesized. They exhibited a high hardness of 18.97 GPa, a good bending strength of 538 MPa, a fracture toughness of 5.88 MPa·m^1/2, and particularly, a high transmittance of 76.28% at 750 nm.