Synthesis and characterization of proton-conducting Ba(Zr0.8-xCexY0.2)O2.9 ceramics

Abstract

X-ray diffraction and micro-Raman scattering have been used to characterize the effects of glycine-to-nitrate (G/N) and zirconium-to-cerium (Zr/Ce) molar ratios on structural properties of proton-conducting Ba(Zr0.8 − xCexY0.2)O2.9 (BZCY) ceramic powders fabricated by using the glycine–nitrate combustion method. Particle sizes of as-synthesized and calcined BZCY powders are estimated by using the Scherrer's formula, and are sensitive to G/N and Zr/Ce ratios. A simple cubic perovskite phase is observed for calcined Ba(Zr0.7Ce0.1Y0.2)O2.9 powders fabricated with G/N ratios of 1/3–3/4. Calcined BZCY (x = 0.0–0.8) powders fabricated with G/N = 1/2 exhibit a single-phase structure and a structural transformation from cubic to possibly rhombohedral for Zr/Ce ≤ 2/6. Particle sizes of as-synthesized and calcined BZCY (x = 0.0–0.8) powders fabricated with G/N = 1/2 vary in the ranges of 5–15 and 34–42 nm, respectively. In-situ temperature-dependent linear shrinkage measurement reveals that smaller-particle BZCY powder can reach densification at a considerable lower temperature.