The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during productio...The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during production were explored. The results show that the solid volume loading of less than 50vol% and the surfactant mass fraction of 6wt% result in a perfect flowability of feedstock; this feedstock is suitable for injection molding. When the debinding time is 8 h at 40°C, approximately 50% of the wax can be solvent debinded. Defects detected during the preparation are traced to improper injection parameters, mold design, debinding parameters, residual stress, or inhomogeneous composition distribution in the green body. The bulk density, Vickers hardness, and fracture toughness of the gas-pressure-sintered Si3N4 ceramic reach 3.2 g/cm^3, 16.5 GPa, and 7.2 MPa·m^1/2, respectively.展开更多
The thermal degradation behaviors of AlN green specimens were studied by thermogravimetry analysis during the ceramic powder injection molding debinding process. The optimum binder composition and the debinding cycle ...The thermal degradation behaviors of AlN green specimens were studied by thermogravimetry analysis during the ceramic powder injection molding debinding process. The optimum binder composition and the debinding cycle were demonstrated by observing the TGA and DTA plots of AlN green specimens and analyzing the microstructure at different temperatures. By adding HDPE into the PW EVA binder used in powder injection molding AlN can effectively reduce the mass lose rate in debinding process and improve the shape retention ability. At last, aluminum nitride ceramic with high room temperature thermal conductivity of 162.5?W·m -1 ·K -1 was produced. [展开更多
基金supported by the National Nature Science Foundation of China (NSFC) under grantNo. 50572049 the National High Technology Researchand Development Program of China ("863 Program") un-der grant No. 2007AA03Z522.
基金financially supported by the National Nature Science Foundation of China (Nos. 51102024 and 21276028)
文摘The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during production were explored. The results show that the solid volume loading of less than 50vol% and the surfactant mass fraction of 6wt% result in a perfect flowability of feedstock; this feedstock is suitable for injection molding. When the debinding time is 8 h at 40°C, approximately 50% of the wax can be solvent debinded. Defects detected during the preparation are traced to improper injection parameters, mold design, debinding parameters, residual stress, or inhomogeneous composition distribution in the green body. The bulk density, Vickers hardness, and fracture toughness of the gas-pressure-sintered Si3N4 ceramic reach 3.2 g/cm^3, 16.5 GPa, and 7.2 MPa·m^1/2, respectively.
文摘The thermal degradation behaviors of AlN green specimens were studied by thermogravimetry analysis during the ceramic powder injection molding debinding process. The optimum binder composition and the debinding cycle were demonstrated by observing the TGA and DTA plots of AlN green specimens and analyzing the microstructure at different temperatures. By adding HDPE into the PW EVA binder used in powder injection molding AlN can effectively reduce the mass lose rate in debinding process and improve the shape retention ability. At last, aluminum nitride ceramic with high room temperature thermal conductivity of 162.5?W·m -1 ·K -1 was produced. [
