Synthesis and antibacterial property of Ag-containing TiO2 coatings by combining magnetron sputtering with micro-arc oxidation

The present work was aimed at developing the antibacterial Ag-containing TiO2 coatings on titanium by combining magnetron sputtering with micro-arc oxidation (MAO). The surface morphology, microstructure, chemical composition and chemical state of the Ag-containing TiO2 layers were characterized using scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The concentration of Ag in the sputtering-deposited AgTi layer on pure titanium was 13.9 wt.%. The MAO coatings were prepared on the AgTi layers under different oxidation duration of 2, 5 and 8 min. The size of the well-separated pores increased by increasing the oxidation duration. Metal Ag existed as Ag0 state was mainly distributed homogeneously inside the pores and the concentrations were 2.36, 2.05 and 1.50 wt.%, respectively. The main TiO2 phases bearing Ca and P species appeared within the structure of the coatings were rutile and anatase. The Ag-containing coating oxidation for 5 min showed excellent antibacterial activity of Escherichia coli (E.coli) within 24 h and the antibacterial rate gradually raised with increasing contact time.