Preparation And Property Research Of Cu-bearing Anti-bacterial Coatings On Titanium

Titanium and its alloys with low elastic modulus, fine biological and goodmanufacture ability, have great potential in applications as diverse as implants,joint prostheses, artificial joints. However, it is a pity that the application oftitanium alloy in clinic also has some problems, and implant-associated bacterialinfections become the main problem which can impedes its spread andapplication. Nowadays, more and more attention is paid to Cu or Ag-bearingantibacterial coatings through surface modification technology. While,antibacterial coatings are prone to fail due to wear and corrosion. To this end,there is an increasing interest in creating an anti-bacterial coating that providesan effect together with excellent wear and corrosion resistance. In this paper,Ti-Cu composite films, which were deposited on the surface of pure titanium bymagnetron sputtering, were dealed with micro-arc oxidation (MAO) and plasmanitriding respectively. The main research results are as follows:In the first chapter, Cu-TiO2coatings with different concentrations of Cuwere prepared by MAO on pre-sputtered Ti-Cu films. The microstructures, composition, chemical states and phase constitution of Cu-TiO2coatings wereanalyzed by scanning electron microscopy (SEM), X-ray photoelectronspectroscopy (XPS) and X-ray diffraction (XRD). The antibacterial propertieswere assessed by two methods: spread plate method and fluorescence staining.MTT method and cell death live staining method were adopted to evaluate thecytotoxicity of modified layer. The corrosion resistance of Cu-TiO2coatingswas evaluated via potentiodynamic polarization method. The experimentalresults demonstrate that the coatings are porous and consist of anatase phase,rutile phase. Ti、Cu mainly exists as TiO2、CuO. The Cu-TiO2coatings exhibitexcellent antibacterial activities without cytotoxicity. The antibacterial rategradually rise with the increase in Cu concentration in the MAO coatings. Thecorrosion resistance of MAO coatings is also improved slightly.Plasma nitriding was adopted to fabricate Cu-bearing Ti-based nitridescoatings (Ti-Cu-N) on pre-sputtered Ti-Cu films. The microstructures wereobserved under SEM equipped with EDS, the phase constitution was analyzedby XRD and the composition was investigated by using GDOES. Theanti-bacterial properties of Ti-Cu-N coatings were evaluated. The wearresistance of the coatings was also investigated. Potential dynamicalpolarization and Nyquist plots were performed to evaluate the corrosionresistance of the layers. The results confirmed that an anti-bacterial Ti-Cu-Ncoating with good adhesive strength to substrate was successfully achieved ontitanium surface. As implied by XRD, the coatings were consisted of TiN, Ti2N, TiN0.3phases. The surface micro-hardness and wear resistance of Ti-Cu-Ncoatings were significantly enhanced after plasma nitriding treatment. Itsmicro-hardness was four times that of pure titanium. The analysis of potentialdynamic polarization curves and Nyquist plots obtained in0.9wt.%NaClsolution suggested that the Ti-Cu-N coatings also exhibited an excellentcorrosion resistance.