Non-linear Behavior for Chemical Expansion in Yttrium-doped Barium Zirconate upon Hydration

The rates of chemical expansion for 20 at % yttrium-doped barium zirconate upon hydration at 100–900 °C under water partial pressures of 0.008 and 0.023 atm have been studied using combined thermogravimetry and high-temperature X-ray diffractometry. Non-linear behavior for the rates of expansion as a function of proton concentration under equilibrium conditions was observed, suggesting that defect interactions impacted the chemical expansion process. Non-linear behavior for the chemical expansion of 20 at % Y-doped barium zirconate under equilibrium conditions was observed upon hydration. This behavior suggests that defect interactions between oxygen vacancies, dopants, and protons play an important role in the chemical expansion process.