Abstract:The high-purity AlON ceramics, AlON/Al₂O₃ and AlON/AlN multiphase ceramics were prepared by pressureless sintering under nitrogen-based atmosphere with raw materials of Al₂O₃, AlN and Al powders. The compositions of the phase were determined by XRD, the fracture appearance was analyzed by SEM. The results indicate: the aluminum oxynitride phase in the AlON ceramics and other multiphase ceramics exist in the form of Al₅O₆N, whose solid-solution zone is 33.4%(mole fraction) AlN belonging to spinel structures. The average grain size of high-purity AlON is about 3 µm. The grain boundary is smooth without other phases. The density is 2.82 g/cm³, the microhardness (10 N) and about bending strength are 1 470 MPa and 94 MPa, respectively.

Key words: pressureless sintering; spinel; aluminum oxynitride; high-purity