Structural and chemical composition analysis of WCN produced by pulsed vacuum arc discharge

The structural and chemical compositions of tungsten carbonitride WCN coatings deposited with a pulsed vacuum arc technique at two substrate temperatures are presented here. Several characterization methods, such as X-ray diffraction, Fourier Transform infrared spectroscopy with photoelectron spectroscopy and transmission electron spectroscopy were used. These characterization methods showed that the coatings consisted of a nano-crystalline matrix that contained several phases of tungsten carbonitride (α-WCN) and tungsten carbide (W2C) and an oxidized phase of tungsten carbide (W2(C,O)). Moreover, The XPS W4f, C1s and N1s peaks and the valence band spectrum indicated the presence of nitrogen, carbon, carbon combined with nitrogen (which is fully bonded to tungsten as nitride), carbide and carbonitride, respectively. pectra showed the existence of NCN, CC, CC, CN and CN bonds. In this energy range, two regions related to D and G bands that correspond to carbon bonds were identified. The nanoindentation technique was used to evaluate hardness. The coatings exhibited a low hardness (lower than 15 GPa), which was potentially caused by the presence of the oxide.