|About this Abstract
||Materials Science & Technology 2011
||MS&T'11 Poster Session
||160 Protective Coatings for Molybdenum Alloys
||Travis Sossaman, Ridwan Sakidja, John Perepezko
|On-Site Speaker (Planned)
Molybdenum based alloys such as TZM and Mo-rich Mo-Si-B alloys have great potential for structural applications at elevated temperatures due to their high melting point and high temperature strength. Their limitations have been poor oxidation resistance in TZM and an extended transient oxidation stage in Mo-Si-B alloys. Previous works have concentrated on MoSi2 coatings which exhibit oxidation resistance. However, CTE mismatch between the coating and substrate and the lack of a barrier to prevent Si diffusion into the substrate are the main challenges. In the current study, the synthesis and performance are evaluated for two Mo-based pack cementation coatings. The borosilicide coating is comprised of a three layer structure: borosilica, Mo-rich silicide, and Mo-rich borosilicide. The aluminosilicide coating is composed mainly of Al-saturated Mo silicide and Mo-poor aluminide layers. These coatings exhibit significant improvement in the oxidation protection of Mo alloys versus the disilicide coatings under various oxidation conditions.