Synthesis of nanocrystallineTi (CxN1−x) thick films on titanium by plasma electrolytic carbonitriding

A novel technique to form Ti(C,N) on titanium, named as plasma electrolytic carbonitriding (PEC/N), is proposed in this paper. The processing is performed by discharge treatments of titanium in an electrolytic solution containing triethanolamine and formamide at 600 V for 0.5–2.5 h using a pulse power supply. XRD, EDAX, and FESEM were employed to characterize the phase component, chemical composition, morphology and grain size of the PEC/N formed films. The results show that the films are composed of Ti(CxN1−x), appearing nanocrystalline and porous, and bond tightly to the titanium substrates. The thickness, ratios of C/N and pores sizes of the films tend to increase with discharge time. When treated for 2.5 h, the film is about 15 μm thick and its hardness is Hv 2083 at the load of 0.2 N.