Pulse Electric Current Sintering and Strength of Zirconia -Dispersed Alumina Ceramics Using Transition Alumina / Zirconia Powders Prepared by the Sol-Gel Method

Abstract

Zirconia-dispersed alumina ceramics were densified by pulse electric current sintering(PECS) using transition alumina / zirconia (5.8 ∼21.0mass%) powders prepared from polyhydroxoaluminum(PHA) - zirconia composite gels at sintering temperatures of 1250 &sim1550°C for holding time of 5 min under uniaxial pressure of 40 MPa. PECS conditions and optimizing of calcination temperature of PHA - zirconia gels were investigated. The rapid sintering by PECS was advantageous to enhance densification in the sintering of transition alumina / zirconia powders, resulting in sintered bodies with a relative density of more than 99%. The content of zirconia and calcination temperature influenced densification and strengthening of the sintered bodies. The bending strength of sintered bodies reached a value as high as about 1.2 GPa by the addition of up to 21.0% zirconia at sintering temperature of 1350°C using sample powders calcined at 1000°C.