Fabrication of High Strength and Toughness Ceramics Using Pulsed Electric-Current Pressure Sintering of ZrO2(Y2O3)–Al2O3 Solid Solution Powders Prepared by the Neutralization Co-precipitation Method

ZrO2 composite ceramics containing 25mol%Al2O3 and a small amount of Y2O3, i.e., 75mol%ZrO2 (0.5～2.0mol%Y2O3: 0.5～2.0Y)–25mol%Al2O3 ceramics, have been fabricated by sintering cubic ZrO2 solid solution (ss) nano-powder prepared via the neutralization coprecipitation method. Their sintering was performed using a pulsed electric-current pressure sintering (PECPS) at 1300～1350˚C for 10 min under 60 MPa in Ar. Dense tetragonal-ZrO2 (ss) ceramics containing α–Al2O3 were composed of 135 − 150 nm grains with a high relative density ≥99.9%. They showed extreme high bending strength (σb≥1 GPa) and high fracture toughness (KIC≥15 MPa • m1/2) simultaneously. FE-SEM observation revealed that these mechanical properties were originated from homogeneous distribution of α–Al2O3 particles around the t–ZrO2 matrix; the precipitation of α–Al2O3 could be achieved by adopting both the (ss) powders containing α–Al2O3 and PECPS.