Hot corrosion behavior of Y₃NbO₇ as thermal barrier coating material

Y₃NbO₇, a simple ternary oxide, has shown excellent high-temperature stability lately. The growing need for more durable thermal barrier coatings in extreme conditions underscores the importance of exploring materials that can resist challenges like hot corrosion. This study examines the thermal barrier properties and hot corrosion characteristics of Y₃NbO₇. Thermal diffusivity and the coefficient of thermal expansion were measured using laser flash technique and dilatometry respectively. The interaction with the thermally grown oxide (TGO) was evaluated by exposing the Y₃NbO₇ powder to Al₂O₃ at high temperatures. To demonstrate the viability of the as-synthesized powder for coating deposition, a plasma sprayed TBC architecture was developed using the Y₃NbO₇ powder. The behavior of as-deposited coating under thermal shock was studied using thermal cycling test. Hot corrosion study was performed on Y₃NbO₇ pellets in a species composed of 32 wt% Na₂SO₄ and 68 wt% V₂O₅ at 900°C. The corrosion products were examined with X-ray Diffraction and Scanning Electron Microscopy. The corrosion phenomenon was found to align with the Lewis acid-base theory, where Y₂O₃ was preferred over Nb₂O₅ for the acidic activity of V₂O₅.