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

Abstract

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 (σ_b≥1 GPa) and high fracture toughness (K_IC≥15 MPa • m^1/2) 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.