Preparation and tribological properties of NiCr–Mo–Ag–O/Mo–V–Ag–O bilayer film at RT-1000 °C

Abstract

The primary objective of this research is to investigate the structure and tribological properties of NiCr–Mo–Ag–O/Mo–V–Ag–O bilayer films in a wide temperature range (RT-1000 °C). The bilayer films were prepared by pulsed laser deposition (PLD) technology, so as to provide the theoretical basis and experimental guidance for the study of the synergistic lubricating effect of Mo and V bimetallic lubricating oxides. The NiCr–Mo–Ag–O composite target was fabricated by the hot-press sintering technique. Subsequently, a NiCr–Mo–Ag–O/Mo–V–Ag–O bilayer film was deposited on Inconel 718 by pulsed laser deposition (PLD). The tribological properties of the film were evaluated by HRT-1000 high-temperature ball-on-disc configuration at RT-1000 °C. The obtained results reveal that the NiCr–Mo–Ag–O target is marked by a compact structure and homogeneous composition. Furthermore, the composite film exhibits a smooth surface and dense structure, comprised of polycrystalline and amorphous phases. The measured hardness and elastic modulus of the film approximated 4.9 GPa and 153.5 GPa, respectively. Additionally, the lowest friction coefficient of the film is about 0.28 at 800 °C. Upon reaching this temperature, the cooperative lubrication resulting from NiMoO4, Ag2Mo2O7, and AgVO3 contributed effectively towards reducing the film's friction coefficient.

Keywords

• NiCr–Mo–Ag–O/Mo–V–Ag–O bilayer film
• Pulsed laser deposition
• Wide-range temperature
• Self-lubricating