Thermal Barrier Coatings for Molybdenum Produced Using Nanopowders

Abstract

The molybdenum is one of the most important refractory metals used in aerospace industry. The main disadvantage of Mo is low oxidation resistance at elevated temperature and the using of protective coatings is necessary. In present article the new types of protective coatings produced by slurry method were developed. The slurries contained Al nanopowder and Si powder as well as non-organic binder (H2CrO4 and water). After immersion and drying the samples with slurries were heat treated at 1000°C in Ar atmosphere. The thickness of obtained coatings was in range 10-20 μm. The presences of phases form Mo-Al as well Mo-Si systems was analyzed using scanning electron microscopy. The developed coatings were used as a bond coat for ceramic layer produced by plasma spray physical vapour deposition method (PS-PVD). In this process the columnar ceramic layer contains yttria stabilized zirconia (YSZ) was obtained wit thickness above 100 μm. The obtained results showed that it is possible to obtain TBC coating on molybdenum contained Al-Si bond coat and outer YSZ ceramic layer. The proposed coating can be used in aerospace applications.