Sliding wear properties of TiAl alloys with/without TiN coatings

Dry sliding wear behavior of TiAl alloys, with and without TiN coatings, has been studied by using the block-on-ring wear test. The TiAl alloys were coated with TiN and a multilayer of TiN and TiCN using multi-are ion plating and plasma chemical vapor deposition, respectively. The results show that wear resistance of the TiAl has been enhanced with the presence of the coatings. It is interesting that the wear rate as a function of the normal load is quite different from general observations, i.e., the wear rate decreased with an increase in the normal load. The properties of the alloy with and without the coatings have been related to microstructural features using X-ray diffraction and scanning electron microscopy.