Interaction of nanostructured Lu₂Si₂O₇/Lu₂SiO₅ double-ceramic layer environmental barrier coatings with CMAS

Silicate is considered a promising material for environmental barrier coatings on hot-section components of aircraft engines. However, the interaction of lutetium silicate coating in the molten calcium‑magnesium-aluminosilicate exposure has not been reported yet. In this study, the interaction of nanostructured Lu₂Si₂O₇/Lu₂SiO₅ environmental barrier coatings (EBCs) with CMAS was systematically investigated at 1300–1400 °C for 25–50 h aiming to clarify the corrosion mechanism of the coatings. Results indicated that the Lu₂Si₂O₇/Lu₂SiO₅ coatings remained intact and the molten CMAS did not penetrate the Lu₂SiO₅ layer after corroded at 1400 °C for 50 h. In addition, the recession layer and TGO layer thicknesses of the coatings after corroded at 1400 °C for 50 h were 82.5 μm and 2.27 μm, respectively. The CMAS corrosion resistance of nanostructured Lu₂Si₂O₇/Lu₂SiO₅ coating is superior to that of ytterbium silicate coatings. The results of this work highlight that the Lu₂Si₂O₇/Lu₂SiO₅ coatings with significantly enhanced CMAS resistance performance might be suitable for advanced EBCs applications.