Synthesis and Mechanical Characterization of Al Casting Produced by Slip Casting and Pressure Less Sintering

Abstract

In this work, the feasibility of using slip casting technique on aluminum powder was studied. It has been found that aluminum powder can be slip cast using sodium alginate as a defloculant binder and water as a liquid vehicle. The results showed that morphology of powder particles plays an important role in slip making, and spherical shaped powder showed better results compared to irregular shaped powder. Slips with water-powder (W/P) ratios of 0.538, 0.600 and 0.666, and with minimum viscosities were casted in plaster molds. Castings were sintered in vacuum furnace at 500 ºC, 550 ºC and 580 ºC for 5h. The results showed that sintered densities were increased with increasing sintering temperature. The optical microscopy of the sintered samples revealed that with the increase in sintering temperature, the fusion of powder particles improved leading to better density and reduced porosity. At an optimum sintering temperature of 550 ºC, mechanical properties were found to be increased while due to decreasing porosity and crystal grain growth lower values of mechanical properties were obtained for the samples sintered at 580 °C. The results of this work showed that there is a great potential to use slip casting process for the manufacturing of aluminum metallurgical parts.