High-temperature corrosion behavior of BaCeO3 in Na2SO4+V2O5 salt mixture

This study examines the high temperature corrosion response and thermal barrier characteristics of BaCeO₃. The phase stability and decomposition behaviour of BaCeO₃ were studied using TG-DSC analysis. The thermal diffusivity and thermal expansion coefficient were determined using Laser Flash Analysis and Dilatometry techniques. Microhardness of the sintered BaCeO₃ was measured using Vickers micro indentation technique whereas the elastic modulus was found using Ultrasonic technique. Corrosion tests were performed on both BaCeO₃ coatings and pellet samples in 32 wt% Na₂SO₄ + 68 wt% V₂O₅ salt melt at 900ºC, and the corrosion process was analyzed using XRD and SEM-EDS. The main corrosion product found in the samples exposed to 32 wt% Na₂SO₄ + 68 wt% V₂O₅ mixture was Ba₃V₂O₈, with small amounts of CeO₂ and BaSO₄. SEM-EDS examination of the corroded samples highlighted the significant corrosive action on BaCeO₃, indicating the acidic leaching of Ba²⁺ ions, which then reacted with the salt mixture. The formation of NaVO₃ intensified atomic mobility, aggravating the corrosion process. Comparing the hot corrosion of BaCeO₃ in pure Na₂SO₄ and V₂O₅ melts with that in the 32 wt% Na₂SO₄ + 68 wt% V₂O₅ mixture confirmed this effect. No discernible peaks corresponding to any Ce-V-O compound were observed in any of the corrosion patterns, suggesting a preference for BaO over CeO₂ in the corrosion process due to its stronger basic nature.