High temperature wear resistance of (TiAl)N films synthesized by cathodic arc plasma deposition

(TiAl)N films were deposited on M2 high speed steel by cathodic are plasma deposition process employing two separate targets of Al and Ti, and the formation behavior of the film was investigated by Auger electron spectroscopy (AES), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The composition of (TiAl)N films was varied by controlling the cathode current ratio (I-Al/I-Ti) of Al and Ti targets at constant are voltage. As the ratio I-Al/I-Ti increased from 0.31 to 0.73, the Al/Ti atomic ratio linearly increased from 0.49 to 1.29. The hardness of (TiAl)N reached 3000 kg mm(-2) at the Al/Ti atomic ratio of 1.10. The high temperature wear resistance of (TiAl)N films was consequently enhanced up to 600 degrees C. A significant improvement of the high temperature wear resistance could be obtained below the temperature of 500 degrees C. The wear mechanisms were discussed and correlated with changes in dynamic friction coefficient and microstructural wear track analysis.