Composite powder prepared of calcium oxide stabilzed ZrO2(CSZ) and NiCr by vacuum sintering is studied,and the effect of additive TiO2 on its properties is discussed. The morphology and phases of the powder were measu...Composite powder prepared of calcium oxide stabilzed ZrO2(CSZ) and NiCr by vacuum sintering is studied,and the effect of additive TiO2 on its properties is discussed. The morphology and phases of the powder were measured and determined by SEM. EPMA, XRD methods and the testing of flowability, bulk density and microhard-ness. The results show that the metallic components in the powder are in homogeneous distribution , the flowability, bulk density and microhardness are superior to the ZrO2-NiCr powder prepared by mechanically mixing. All components in the coating made of the composite powder are well-distributed because of avoiding segregation in the middle of mixing. It proves that the composite powder is an excellent material for plasma spraying.展开更多
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Composite powder prepared of calcium oxide stabilzed ZrO2(CSZ) and NiCr by vacuum sintering is studied,and the effect of additive TiO2 on its properties is discussed. The morphology and phases of the powder were measured and determined by SEM. EPMA, XRD methods and the testing of flowability, bulk density and microhard-ness. The results show that the metallic components in the powder are in homogeneous distribution , the flowability, bulk density and microhardness are superior to the ZrO2-NiCr powder prepared by mechanically mixing. All components in the coating made of the composite powder are well-distributed because of avoiding segregation in the middle of mixing. It proves that the composite powder is an excellent material for plasma spraying.
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.
