Densification behaviour and physico-mechanical properties of porcelains prepared using spark plasma sintering

Porcelain powder was consolidated using spark plasma sintering (SPS) at a constant heating rate of 100 degrees C min(-1) to peak temperatures ranging from 1000 to 1200 degrees C and was observed to sinter at relatively low temperature similar to 920 degrees C under the SPS conditions while conventional sintering requires similar to 1050 degrees C. SPS produced densification rates about 10 times greater than conventional sintering. The dwelling step at the optimal peak temperature was negligible due to rapid flow of the molten glass assisted by applied pressure. SPSed samples exhibited denser microstructures, resulting in improved physico-mechanical properties compared with conventionally sintered samples such as apparent bulk density improved from 2.38 to 2.48 gcm(-3), Vickers hardness improved from 3-5 to 6-7 GPa, and fracture toughness improved from 2-3 to 4-6 MPa m(1/2).