Intermediate temperature ionic conduction in Mg2 +-doped ZrP2O7 ceramics

A new series of Zr1 − xMgxP2O7 (x = 0.00, 0.03, 0.06, 0.09, and 0.12) ceramic samples were prepared by solid-state reaction method. The ceramic samples of x = 0.00–0.09 exhibited a single phase structure, and the doping limit of Mg2 + in ZrP2O7 was at least x = 0.09. Densification increased with increasing of Mg2 + doping level, the highest relative density reached 97.1% for the sample of x = 0.09. The conduction in ceramic samples was investigated electrochemically at 300–600 °C. Among the ceramic samples studied, the highest conductivity was observed for the sample of Zr0.91Mg0.09P2O7 to be 1.34 × 10− 4 S·cm− 1 in unhumidified air and 1.08 × 10− 4 S·cm− 1 in unhumidified hydrogen at 600 °C. For the sample of Zr0.91Mg0.09P2O7, the conductivity was nearly independent of oxygen pressure, pO2, in the range of 1–10− 22 atm, and the ionic transference numbers were close to unity, indicating that the ceramic sample was almost a pure ionic conductor under both oxidizing and reducing atmospheres.