Metallic bond coats for thermally-sprayed thermal barrier coatings applied to aero-engines and industrial gas turbines: review and prospect

Abstract

The MCrAlY bond coats used for thermally-sprayed thermal barrier coatings applied to aeroengines and industrial gas turbines are reached their temperature limits. The further development is aiming to extend service life, low production cost and compatibility with new fuels. The new MCrAlYs have to be oxidation resistant and spallation resistant, and able to prevent SRZ formation caused by the diffusion with superalloy substrate, and to avoid the damage of thermo-mechanical properties. This paper reviewed recent developments in this area, and proposed a composite structured low-β / near-γ′ type MCrAlY with a very low ϕ value and CTE closed to Al2O3 to achieve the target. This approach may be cost effective, and more attractive to aeroengine and industrial gas turbine manufacturers, as well as coating developers and research institutions. Meanwhile, big data analysis will help to design new coating composition, speed up the development process and reduce R&D cost, lead to the findings of more durable thermal barrier coatings for aeroengine and industrial gas turbine applications.

Keywords

• gas turbine
• thermal barrier coating
• metallic bond coat
• durability
• low cost
• alloy design