Effects of nitriding on the microstructure and properties of VAlTiCrMo high-entropy alloy coatings by sputtering technique

Abstract

The VAlTiCrMo and (VAlTiCrMo)Nx coatings were prepared by sputtering V–Al–Ti–Cr–Mo splicing targets. The microstructure and chemical composition were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and transmission electron microscope (TEM). The high-entropy alloy coating and the corresponding nitride coating have body-centered cubic (BCC) and face-centered cubic (FCC) structures respectively. Nitriding changes the phase structure and growth mode of the high-entropy coating, and the synthesized high-entropy nitride coatings are more compact. Meanwhile, the introduction of nitrogen leads to severe lattice distortion, which improves the mechanical properties of the high-entropy coating. As the nitriding degree increases, the corrosion resistance of the high-entropy nitride coatings in 3.5 wt% NaCl solution is improved. The synthesized (VAlTiCrMo)Nx coating exhibits optimized mechanical properties and nobler corrosion resistance when the N2 flow is 800 sccm.