COMBINED OXIDATION AND EROSION RESISTANT COATINGS FOR TI AND TIA1 ALLOYS

Despite improvements in alloying and processing, the oxidation resistance of titanium and titanium aluminide alloys is one of the major factors limiting their use in advanced propulsion equipment. In addition, there are certain applications for these alloys that would benefit from improved erosion or wear resistance. It has been determined that combined oxidation and wear/erosion resistant protective coatings may improve the long term survival, or more importantly, the economic longevity of components made from Ti- and TiAl-alloys. The proposed work will explore the processing and properties of new types of composite coatings based on (Al, Cr) 3Ti alloys. These base alloys have already demonstrated their excellent oxidation resistance and ability to be processed into protective coatings for Ti- and TiAl-alloys. The new composite coatings will be reinforced by fine scale titanium carbide particles and fabricated by air plasma spray. The carbide reinforcements will be incorporated by both the blending of plasma spray powders and by the creation of pre-alloyed powders by mechanical alloying techniques. It is automotive markets and could be extended for use on aluminum and magnesium based alloys.