Consolidation of alumina toughened zirconia by two-step sintering

Sol-gel-synthesized ZrO2-based nanoparticles, containing 1.5mol% Y2O3 used as dopant and 25mol% Al2O3 (abbreviated as ZrO2(1.5Y)-25Al2O3), were densified by pulsed electric current sintering (PECS) accompanied with a two-step heating profile. Particularly, sintering was carried out in the temperature range from 1050 to 1200°C for 10min, followed by dwell at 1325°C for 10min. The ZrO2-based ceramics achieved by the two-step sintering was fully dense, containing 98 vol.% of tetragonal ZrO2 phase. Morphology of the sintered samples showed the submicron grains with uniform size distribution. Although the second-step sintering temperature was fixed at 1325°C, the mean grain size was increased along with the increase in the first-step sintering temperature. In addition, the material characterization of the samples after the first-step heating was tested to investigate the influence of the first-step sintering on the consolidation of ceramics achieved via the two-step sintering.