Preparation and characterization of structure and properties of nanoTiSiN films deposited on Mg alloys

The work aims to improve corrosion and wear resistance of Mg alloys, TiSiN composite films were prepared on two groups Mg alloys by reactive magnetron sputtering in mixed Ar+N₂ atmosphere by sputtering Ti-Si target. Chemical composition, surface morphology, crystalline structure and grain size were investigated by X-fluorescence (XRF), scanning electron microscopy (SEM), atomic force microscope (AFM) and grazing incidence X-ray diffraction (GIXRD), respectively. The corrosion behavior and wear resistance were studied by electrochemical workstation in 3.5% NaCl solution and ball-on-disc tribometer in air, respectively. Results show that the Ti, Si content of film is close to target material and present an alternating ring distribution on the whole coating surface, and Ti, Si elements in Mg8Li film are more evenly distributed. Crystal structure of films is mainly composed of Ti₂N and TiN, the grain size and roughness of AZ31 film is lower than Mg8Li film. The corrosion current density of coatings decreased by three orders of magnitude, the friction coefficient is less than 0.4 and wear loss rate in an order of 10⁻⁶ m³·N⁻¹m⁻¹ magnitude. The films have good corrosion and wear resistance, the properties of thin film is affected by surface roughness and crystal size.