Cr1-chi Al chi C films were deposited on high-speed steel by RF reactive magnetron sputtering. In this study, we aimed to identify the effect of the Al content on the properties of Cr1-chi Al chi C films. We found that Cr1-chi Al chi C films exhibited a fine columnar grain microstructure with some special characteristics, such as high hardness of Hv 1426, a low friction coefficient of 0.29, and a large contact angle of 90 degrees for x = 0.18. Furthermore, an increase in Al content resulted in a decrease in film hardness and an increase in contact angle. Moreover, on annealing at 923 K, the mechanical properties of the films improved and a dense protective film of complex Cr2O3 and Al2O3 oxides was formed on the surface for better wear resistance, which will ultimately increase the lifetime of the high-speed steel substrate. (c) 2006 Elsevier B.V. All rights reserved.