Pressureless Sintering of Calcium Alpha Sialons

摘要

In this work, the oxygen rich compositions near the intersection of the α-SiAlON plane with the Si_3N_4-AlN-CaO plane were investigated. The pressureless sintering behaviour was explained in terms of the phase evolution and stability of secondary phases. It was possible to produce low porosity α-SiAlON by pressureless sintering where excess second phase for the formation of α-SiAlON was present. Preliminary mechanical property investigations for pressureless sintered material resulted in a MOR of 550 MPa, an elastic modulus of 240 GPa, a Vickers hardness of 14.4 GPa and a fracture toughness of 4.5 MPa.m~(1/2).