Fabrication of Alumina Parts Using Injection Molding

In this study، the optimum conditions for producing alumina parts by means of injection molding was investigated. First، different binder systems were prepared and their rheological characteristics were investigated. Then binders containing 1، 2 and 4 weight percent of stearic acid was chose. Three different pastes were prepared with 20 wt% binder (including 1، 2 and 4wt% stearic acid) and 80 wt% alumina. Studying rheological behavior of aforementioned compounds proved that using the binder containing 2 wt% of stearic acid as surfactant shows the lowest viscosity which has a constant alteration against shear rate. In continuous، to attain to the proper composition of powder and binder and achieve high density، different percents of powder and binder was prepared. Rheometric investigations showed that the composition containing 81. 5 wt% of alumina and 18. 5 wt% of binder was proper to choose. After injecting the prepared feed stocks into the mold and producing samples، thermal analysis was carried out to distinguish the proper thermal cycle of debinding process. Finally sintering was carried out at 1600 °C for 3 hours. Bending strength and density of sintered samples was 186 MPa and 3. 68 g/cm3، respectively.