Hot Isostatic Pressing of Y₂O₃-Doped La₂Zr₂O₇ Prepared by the Hydrazine Method

Abstract

Pyrochlore La₂Zr₂O₇ containing 8 mol% Y₂O₃ crystallizes at 825°to 885°C from an amorphous material prepared by the hydrazine method. The lattice parameter is α=1.0751 nm; this value is smaller than that (α=1.0793 nm) of pure La₂Zr₂O₇. Dense Y₂O₃-doped La₂Zr₂O₇ ceramics (99.7% of theoretical) with an average grain size of 3.8 μm have been fabricated by hot isostatic pressing for 2 h at 1500°C and 196 MPa. They exhibit electrical conductivity of 1.6 S⋅m^-1 at 1000°C. Activation energies are 0.82 and 0.58 eV for initial (400°-540°C) and final (540°-1000°C) stages, respectively.