Hot corrosion characteristics of SrCeO3 as thermal barrier coating material

Abstract

This study investigates the thermal barrier and hot corrosion characteristics of SrCeO₃, a perovskite-structured material, synthesized via the solid-state method using SrCO₃ and CeO₂ as precursors. The crystal structure was confirmed by x-ray diffraction (XRD), and the elemental composition matched theoretical values based on energy-dispersive spectroscopy (EDS). Thermal analysis showed that SrCeO₃ is phase stable up to 1400ºC, with thermal conductivity lower than that of yttria-stabilized zirconia (YSZ), though the coefficient of thermal expansion was similar. Mechanical properties, including elasticity, hardness, and fracture toughness, were found to be inferior to those of YSZ. Additionally, SrCeO₃ showed incompatibility with thermally grown oxide (TGO) layers, reacting with Al₂O₃ at high temperatures. Atmospheric plasma sprayed coatings of SrCeO₃ showed minimal decomposition, with only trace amounts of Sr(OH)₂ and CeO₂ formed during spraying. The high-temperature corrosion behavior of SrCeO₃ was examined in a 32 wt% Na₂SO₄ + 68 wt% V₂O₅ salt mixture and pure V₂O₅ at 900ºC for 30 h. In the salt mixture, Sr₃V₂O₈ was the primary corrosion product, whereas SrV₂O₆ formed in pure V₂O₅. The Na₂SO₄ in the salt mixture increased the corrosive activity by enhancing V₂O₅ reactivity. Importantly, no Ce-V-O corrosion product was observed, confirming that corrosion followed the Lewis acid-base principle.