Oxidation behavior of niobized TiAl by plasma surface alloying

Plasma surface alloying of element Nb in TiAl-based alloys and the oxidation behavior were studied. The composition and microstructure of the surface alloyed layers were investigated by means of scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD). The experimental results indicate that the diffusion layers are formed on the TiAl substrate during the plasma niobizing process. The result from oxidation resistance investigation shows that plasma niobizing greatly improves the oxidation resistance of TiAl compared with the untreated TiAl. The role of element Nb for improving the oxidation resistance is considered to be achieved by strengthening the activity of Al, which is induced by the plasma niobizing process.