The effect of molybdenum content on microstructure, mechanical, tribological and corrosion behavior of Zr-Mo-N composite films

Abstract In this research, Zr-Mo-N composite films with different Mo content were deposited by multi-target magnetron sputtering device. The first-principle calculation, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), nano-indentation, high-temperature sliding wear tests and electrochemical workstation were used to characterize the microstructure, mechanical, tribological and corrosion behavior of Zr-Mo-N films. The results showed that molybdenum atoms replaced the zirconium atoms in ZrN lattice to form a (Zr, Mo) N solid solution. Zr-Mo-N films exhibited a face-centered cubic (fcc) structure less than the content of 11.3 at.% Mo, and showed a double phase of fcc-ZrN and fcc-Mo2N when Mo content reached 11.3 at.%. With the increase of Mo content, the hardness first increased and then decreased, which maximum value was obtained at 11.3 at.% Mo. The friction coefficient at room temperature decreased monotonically, meanwhile the wear rate first decreased and then increased with the best value showed at 16.9 at.% Mo. The wear test under elevated temperature showed the friction coefficient of films initially increased and then decreased with the raising test temperature, as well as the monotonically increase of wear rate. The films represent the best corrosion resistance when the Mo content is 11.3 at.%.