Preparation of alumina ceramic by injection molding

Alumina (Al₂O₃) ceramics were prepared by injection molding with a multi-component binder. The effects of paraffin content, solid loading on the viscosity of feedstock and property of green body were discussed. The effects of sintering temperature on the property and microstructure of sintering body were investigated. The results show the viscosity was suitable for injection molding with paraffin content of 40wt% and solid loading of 52vol%, and the green body presented optimum properties. The green body exhibites a uniform microstructure and mechanical strength as high as 25 MPa, which can fully meet the machining requirement. As the sintering temperature increases from 1560℃ to 1640℃, the relative density increases. Al₂O₃ sintered at 1600℃ shows the highest flexural strength (422±40 MPa) and high relative density. Also, SEM image shows that crystal grain of sintering bodies was fully developed, which demonstrates that the temperature of 1600℃ is a best sintering temperature.