Hot corrosion behavior of magnesia-stabilized ceramic material in a lithium molten salt

The isothermal and cyclic corrosion behaviors of magnesia-stabilized zirconia in a LiCl-Li₂O molten salt were investigated at 650 °C in an argon atmosphere. The weights of as-received and corroded specimens were measured and the microstructures, morphologies, and chemical compositions were analyzed by scanning electron microscopy, X-ray energy dispersive spectroscopy, and X-ray diffraction. For processes where Li is formed at the cathode during electrolysis, the corrosion rate was about five times higher than those of isothermal and thermal cycling processes. During isothermal tests, the corrosion product Li₂ZrO₃ was formed after 216 h. During thermal cycling, Li₂ZrO₃ was not detected until after the completion of 14 cycles. There was no evidence of cracks, pores, or spallation on the corroded surfaces, except when Li was formed. We demonstrate that magnesia-stabilized zirconia is beneficial for increasing the hot corrosion resistance of structural materials subjected to high temperature molten salts containing Li₂O. - Highlights: •Corrosion mechanism of MSZin LiCl-Li₂O molten salt is proposed. •Formation of Li₂ZrO₃is main corrosion mechanism. •There were no cracks, pores and spallation after corrosion test. •MSZ shows high corrosion resistance to LiCl-Li₂O molten salt.