Friction and wear properties of TiCN coatings sliding against SiC and steel balls in air and water

The TiCN coatings were deposited on WC cemented carbides using enhanced cathodic arc magnetron sputtering. The topography of TiCN coatings were observed using scanning electron microscopy (SEM), the composition and structure of TiCN coatings were analyzed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The friction and wear properties of TiCN coatings sliding against SiC and steel balls in air and water were investigated using ball-on-disk tribometer. The results showed that the TiCN coatings had a strong (111) preferred orientation. The friction coefficient and the specific wear rates of the TiCN/SiC tribopairs in air were higher than those in water. When the TiCN coatings slid against SiC balls in water, the friction coefficient and the specific wear rates first decreased, and then increased with the normal load, but decreased linearly with the sliding velocity. The lowest friction coefficient of 0.171 was obtained at 3 N and 0.4 m/s, while the lowest specific wear rate of the TiCN coatings was 2.3 x 10(-6)mm(3)/Nm at 6 N and 0.1 m/s. The TiCN coatings were worn out when the normal loads were higher than 6 N. When the TiCN coatings slid against the SUJ2 and SUS440C balls in water, the friction coefficient increased to 0.271 and 1.026 respectively. The EDS analysis showed that Fe and 0 elements existed on the wear track. This indicated that the tribochemical reaction occurred at the friction contact area. (C) 2011 Elsevier B.V. All rights reserved.