High-temperature mechanical properties and oxidation resistance of SiCf/SiC ceramic matrix composites with multi-layer environmental barrier coatings for turbine applications

Continuous silicon carbide fiber reinforced silicon carbide (SiC_f/SiC) ceramic matrix composites are considered promising materials as high-temperature components of advanced aero-engines. However, due to their susceptibility to oxidation and corrosion at high temperature, environmental barrier coatings (EBCs) must be applied on the surface of SiC_f/SiC. In this study, Si/Y₂SiO₅/LaMgAl₁₁O₁₉ (LMA) multi-layer EBCs were fabricated to protect SiC_f/SiC by using atmospheric plasma spraying (APS). The high-temperature tensile fatigue performance of SiC_f/SiC with and without EBCs was evaluated. The results indicated that EBCs significantly improved the tensile fatigue properties of SiC_f/SiC at high temperature in air atmosphere. Meanwhile the bending strength of specimens after isothermal aging or not was also tested. The multi-layer EBCs in this study may be a promising EBCs system for SiC_f/SiC after some improvements.