Si3N4 ceramics were prepared by pressureless sintering at 1 650 ℃ in nitrogen atmosphere using Si3N4 powder as main starting material and adding nano Al203 powder （3%, 6%, 9%, 12%, and 15% in mass, the same hereinaf...Si3N4 ceramics were prepared by pressureless sintering at 1 650 ℃ in nitrogen atmosphere using Si3N4 powder as main starting material and adding nano Al203 powder （3%, 6%, 9%, 12%, and 15% in mass, the same hereinafter）. The bending strength and fracture toughness （KIC） of the specimens were detected.The microstructure and phase compositions of the specimens were analyzed. The results show that SigN4 ceramics can be prepared by pressureless sintering when adding 9% -12% nano-A1203 as active reactant, which dissolves in Si3N4, in-situ forming non-oxide SiAION. The obtained Si3N4 ceramics have the maximum bending strength of 710. 86 MPa and KIC of 8. 61 MPa · m1/2 The exceUent properties come from many interwoven structures distributed uniformly in the ceramics matrix, u,hich is composed of big and firm plate-like β-Si3N., hexagonal SiAION and sheet Si2N2 0.展开更多
文摘Si3N4 ceramics were prepared by pressureless sintering at 1 650 ℃ in nitrogen atmosphere using Si3N4 powder as main starting material and adding nano Al203 powder （3%, 6%, 9%, 12%, and 15% in mass, the same hereinafter）. The bending strength and fracture toughness （KIC） of the specimens were detected.The microstructure and phase compositions of the specimens were analyzed. The results show that SigN4 ceramics can be prepared by pressureless sintering when adding 9% -12% nano-A1203 as active reactant, which dissolves in Si3N4, in-situ forming non-oxide SiAION. The obtained Si3N4 ceramics have the maximum bending strength of 710. 86 MPa and KIC of 8. 61 MPa · m1/2 The exceUent properties come from many interwoven structures distributed uniformly in the ceramics matrix, u,hich is composed of big and firm plate-like β-Si3N., hexagonal SiAION and sheet Si2N2 0.
