The Effect of Microwave Energy on the Slip Casting of Aqueous Ceramic Suspensions

Slip casting is a simple, low-cost, ceramic manufacturing process that is widely used for the production of engineering components. However, it suffers from being relatively slow. Raising the slip temperature during slip casting is known to increase the casting rate, possibly by causing a decrease in slip viscosity and by affecting the state of dispersion of the slip. The current work examines the potential for using microwave energy to achieve accelerated slip casting of aluminium oxide based slips and attempts to shed light on the underlying mechanisms. It was found that increasing the slip casting temperature results in an acceleration of the casting rate and that the use of microwave energy causes a greater degree of acceleration than convectional heating. In addition, measurements indicate that the rate of water movement through the plaster of paris mould is increased more than the rate of water uptake by the mould, particularly during the microwave-accelerated casting process. This suggests that at least part of the acceleration mechanism is due to faster moisture movement within the mould.