Effect of N₂ partial pressure on comprehensive properties of antibacterial TiN/Cu nanocomposite coating

Foreign body reactions to the wear debris and corrosion products from the implants, and bacterial infections are the main factors leading to the implant failures. In order to resolve these problems, the antibacterial TiN/Cu nanocomposite coatings with various N₂ partial pressures were deposited on 304 stainless steels (SS) using an arc ion plating (AIP) system, named TiN/Cu-x (x = 0.5, 1.0, 1.5 Pa). The results of X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and scanning electron microscopy showed that the N₂ partial pressures determined the Cu contents, surface defects, and crystallite sizes of TiN/Cu nanocomposite coatings, which further influenced the comprehensive abilities. And the hardness and wear resistances of TiN/Cu coatings were enhanced with increase of the crystallite sizes. Under the co-actions of surface defects, crystallite sizes, and Cu content, TiN/Cu-1.0 and TiN/Cu-1.5 coatings possessed excellent corrosion resistance. Besides, the biological tests proved that all the TiN/Cu coatings showed no cytotoxicity with strong antibacterial ability. Among them, TiN/Cu-1.5 coating significantly promoted the cell proliferation, which is expected to be a novel antibacterial, corrosion-resistant, and wear-resistant coating on the surfaces of medical implants.