High-temperature oxidation behaviours of rare earth-based pyrochlore structured A₂B₂O₇/yttria-stabilized zirconia thermal barrier coatings

Abstract

Addressing the challenge of cost-effectively synthesizing stable thermal barrier coating materials has been a significant hurdle. This study describes the bulk synthesis of stannate-based pyrochlore compounds, specifically erbium tin oxide (Er2Sn2O7) and yttrium tin oxide (Y2Sn2O7). These synthesized pyrochlore oxides and commercially available yttria-stabilized zirconia (YSZ) were coated onto nickel super alloy. The coated specimens were subjected to thermal oxidation kinetics studies at 900 ± 5°C for 200 h, and alterations in physico-chemical characteristics, modifications in surface morphology, and variations in the composition of thermal barrier coating (TBCs) before and after exposure to oxidation conditions were evaluated. Oxidation kinetics results demonstrate that Er2Sn2O7 pyrochlore oxide has better performance than other Y2Sn2O7 and commercial YSZ TBC materials in high-temperature thermal barrier systems.