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A surfactant free growth method was proposed to get thick MnSi∼1.7 film by exposure of Si(111) substrates to MnCl2 vapor in quartz ampoules. Prior to the growth of silicide film, an amorphous nano SiOx capping layer was introduced on the Si substrate. The capping layer changes the elemental diffusion flux to the reaction interface and facilitates the growth of single phase MnSi∼1.7 film. Optical absorption spectrum demonstrates the existence of a direct band gap∼ 0.78 eV, which agrees well with the theoretical one obtained by density functional theory modeling.

A nanostructured magnesium silicide (Mg 2 Si) was fabricated via heating SiC substrate in an Mg vapor by reactive deposition techniques and characterized by Scanning electron microscopy (SEM) and X-ray Diffractometer (XRD). The electrochemical performances were tested by a galvanostatically charge/discharge method. A maximum discharge capacity of 365 mA h/g was measured by Mg 2 Si nanoparticle electrode with a good cycle performance. A Mg 2 Si thin film was also prepared by the reaction of Si substrate with Mg vapor for comparison. The Mg 2 Si film showed a high initial discharge capacity up to 2238 mA h/g. However, the capacity decayed quickly to less than 20 mA h/g after 20 cycles. This work provides a feasible way to fabricate the silicide based nanostructured materials for Li ion battery.

Surface treatment is of particular interest to slow down the in vitro degradation of Mg-based implants. In this work, micro arc oxidation (MAO) coating was fabricated on Mg–Zn–Ca alloy which has been developed by our group especially for the application of bio-implants. Evident improvement in corrosion resistance was obtained although the MAO coating was porous. In order to further diminish the contact with SBF, a composite coating was prepared by introducing a TiO 2 layer by liquid phase deposition (LPD) method on the MAO pre-treated alloy. The coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results of the potentiodynamic polarization experiments showed that, compared with the bare alloy, the corrosion potential of TiO 2 /MAO/alloy increased from −1.771 to −1.607 V. At the same time, the corrosion current density decreased from 1.43 × 10 −4 A cm −2 to 5.69 × 10 −7 A cm −2 . The improvement of degradation resistance in SBF was ascribed to both barrier effect and enhanced interface condition. The OH-terminated MAO layer surface can make the TiO 2 layer anchor tightly on the MOA surface. The chemical bonding of composite layer induced by Mg 2+ cations bridges was also analyzed.

A composite coating was fabricated on home-developed Mg–Zn–Ca alloy to improve its biocorrosion resistance in simulated body fluid (SBF, Kokubo solution). The coating was prepared by micro arc oxidation (MAO) of the alloy, followed by dip-coating in chitosan solution. The coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The electrochemical performance of the MAO, chitosan and chitosan/MAO coated alloys was evaluated by anodic polarization measurements in SBF. After being coated by composite coating, anticorrosion performance was significantly enhanced, while single MAO or chitosan coating only improved anticorrosion properties within a limited range. The barrier effect and interface condition of composite coating were analyzed and related with the improvement in electrochemical performance. The present result indicates that fabrication of composite coatings is a significant strategy to slow down the degradation of Mg alloys, thus enhancing the potential of using Mg alloys as bio-implants.

Magnesium (AZ31) alloy was employed as the carrier of mesoporous TiO2 films catalyst. TiO2 films were prepared by the liquid phase deposition (LPD) method. The films transform to anatase at 189°C. The anatase phase was certified by X-ray diffractometer (XRD). The surface of the films consisted of particles whose diameter was about 150 nm. There were protuberances and micropores on the particles and their size was about 10 nm. The thickness of the films was about 6 μm. The films can catalytically decompose the methylene blue under the irradiation of the visible light. The films sintered in the vacuum furnace have high photocatalysis activity compared with those sintered in the air atmosphere. The Mg and Al atoms can diffuse from the substrate to the films. The Mg2+ ionic can help to generate the cavity and the oxygen defect. The vacuum sintering condition can benefit formation of the oxygen defect. These defects enhanced the photocatalysis.