Al₂O₃-Compositional Dependence of Mechanical Properties of ZrO₂ Based Ceramics Fabricated from ZrO₂(Y₂O₃)-Al₂O₃ Solid Solution Powders

Abstract

ABSTRACT

ZrO₂ composite ceramics containing 10~30 mol% Al₂O₃ and 1.5 mol% Y₂O₃, i.e., 90~70 mol% ZrO₂(1.5 mol% Y₂O₃)-10~30 mol% Al₂O₃ ceramics, have been fabricated by sintering cubic ZrO₂ solid solution (ss) nano-powders prepared via the neutralization co-precipitation method. The sintering was performed using a pulsed electric-current pressure sintering (PECPS) at 1598 K for 10 min under 50~60 MPa in Ar. Dense tetragonal-ZrO₂ (ss) ceramics containing α-Al₂O₃ were composed of 277-130 nm grains. FE-SEM observation revealed that their microstructures, that is the grain sizes of both t-ZrO₂ (ss) and α-Al₂O₃, and the distribution of α-Al₂O₃ particles, were much influenced by the content of α-Al₂O₃. The best mechanical properties of extreme high bending strength (σ_b ≥ 1 GPa) and high fracture toughness (K_IC ≥ 15 MPa • m^1/2) simultaneously were obtained at the composition of 25 mol% Al₂O₃ with a high relative density 99.9 %, as the same composition reported for the HIP sintered ZrO₂(2~3 mol% Y₂O₃)-Al₂O₃ composite ceramics.