Fabrication of ZrO2 Solid Solution Ceramics Containing Al2O3 Having High Bending Strength (σb≥1 GPa) and High Fracture Toughness (KIC≥20 MPa·m1/2) Simultaneously by Pulsed Electric-current Pressure Sintering (PECPS)

Abstract

ZrO2 solid solution (ss) ceramics containing 25mol%Al2O3 and 1.125mol%Y2O3, i.e., 75mol%ZrO2(1.5mol%Y2O3:1.5Y)-25mol%Al2O3 ceramics, have been fabricated by sintering cubic ZrO2 (ss) nanoparticles prepared via a sol-gel process with a pulsed electric-current pressure sintering (PECPS) at 1100°∼1350°C for 10 min under 60 MPa in Ar. Dense tetragonal-ZrO2 (ss) ceramics with a small amount of α-Al2O3, sintered at 1300° to 1350°C, were composed of 0.2-0.3 μm grains with a high relative density of ≥97.5 %. They showed extreme high bending strength (σb≥1 GPa) and high fracture toughness (KIC≥20 MPa·m1/2) simultaneously. High-resolution TEM observation revealed that these mechanical properties were originated from homogeneous distribution of α-Al2O3 particles in the nanometer-grain matrix of t-ZrO2; the precipitation of α-Al2O3 could be achieved by adopting the solid solution powders containing α-Al2O3 and PECPS.