A novel environmental barrier coating material of AlHfTaO6 with low thermal conductivity and high corrosion resistance

Abstract

Environmental barrier coating (EBC) is of great important for silicon carbide-based ceramic matrix composites (SiC-CMCs) applied in aero-engine. However, conventional EBC materials like silicates have insufficient corrosion resistance to water vapor and molten salt in extremely harsh environments of aero-engine. We herein develop a novel EBC material of AlHfTaO₆. It not only shows a strong resistance to high temperature water vapor and molten salt corrosion, but also has a low thermal conductivity of 1.4–1.8 W·m⁻¹·K⁻¹ from room temperature to 1500 °C. Additionally, the thermal expansion coefficient of AlHfTaO₆ (5 × 10⁻⁶–8 × 10⁻⁶ K⁻¹) closely matches that of SiC-CMCs (4 × 10⁻⁶–6 × 10⁻⁶ K⁻¹), suggesting excellent compatibility and integration during service. These results demonstrate that AlHfTaO₆ is a promising environmental barrier coating material, and may have great benefits for improving working temperature and service life of SiC-CMCs in aero-engine.