Wear resistance of TiAl intermetallics by plasma alloying and plasma carburization

The duplex treatment of plasma carburization on plasma alloyed TiA1 with Nb was carried out in order to improve the tribological properties of TiA1. Dry sliding wear behavior of the duplex-treated TiA1 was investigated by using pin-on-disk wear testing method with the counterface of a high carbon steel compared with those of untreated and plasma-carburized TiA1. The microstructure of the existed phases in the surface layer and the distribution of the carbon element in the surface layer were characterized using optical microscopy, scanning electron microscopy, glow discharge spectrum and X-ray diffraction. The results showed that the duplex-treated TiA1 is effective in enhancing the wear resistance of TiA1 due to a low coefficient of friction and a low wear volume. The existence of NbC and Nb2C carbides and excessive carbon are the main contribution to the tribological performance of TiA1. At the same time, an increased thickness in the hardened layer by NbC and NbC carbides and carbon element is also effective in improving the tribological performance of TiA1. (C) 2006 Elsevier B.V. All rights reserved.