Enhanced casting rate by dynamic heating during slip casting

The slip casting process is widely used to consolidate ceramic particles from aqueous suspensions to form green compacts, particularly those with complicated shapes. Raising the slip temperature during slip casting is known to increase the casting rate, this is believed to be via a decrease in water viscosity. However, differences have been observed when using convection and microwave heating to raise the temperature. In the present work, it has been found that the use of short-pulses of microwave energy to heat the casting system dynamically causes a greater degree of acceleration than when using conventional radiant heating. The increased uptake of water from the slip by the porous mould is believed to be indicative of a vaporisation–condensation cycle mechanism. A negative pressure would be created during the condensation stage of the cycle, acting as an additional suction force to the capillary action and hence accelerating the casting process.