TiAl Surface Coating on Titanium by Plasma Transferred Arc Surfacing and Its Oxidation Behavior

In order to improve high-temperature oxidation resistance of titanium, fabrication of TiAl intermetallic compounds as a surface layer by plasma transferred arc surfacing (PTA surfacing) was investigated. Powder of unalloyed aluminum was fed into the plasma during the PTA surfacing and TiAl-based intermetallic layers were successfully synthesized. The surface layers had no cracks and porosities with optimized conditions of the PTA surfacing. The surface layers that largely consist of TiAl and Ti3Al phase could be achieved, while the microstructures of them were significantly influenced by the conditions such as the arc current. The TiAl-based layers exhibited high resistance to oxidation under isothermal conditions at 1073 K or less and had practically the same resistance as SUS310S had.