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Iowa State University and Ames Laboratory researchers have developed a process to control and retain halogen alloy additions to titanium aluminide powders in the form of a surface film.

Doping of titanium aluminide with small concentration of halogen atoms has been demonstrated to greatly enhance the resistance of the metal to oxidation.  Previous methods to create a thin, halogen containing exterior film such as ion-implantation have proven ineffective, and alternate powder metallurgy approaches provide little control over the amount of halogen incorporated into the powders.  The tailored in situ powder coating approach presented here provides for the incorporation of halogen in an alloy microstructure as an oxy-halogen by powder consolidation.  This chemical reservoir of oxy-halogen promotes renewable formation of a nanometer-scale exterior protective film with higher thermal stability and increased surface oxidation resistance.

• Reduces pyrophoriscity of atomized titanium aluminide powder

• Increases oxidation resistance for high temperature operation

Titanium powders for high temperature components

1: "Performance of Composite Pour Tubes for Titanium Close Coupled Atomization”, A. Heidloff, TITANIUM 2012, Hilton Atlanta, Atlanta, October 2012.