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a-C/a-C:Ti multilayer films were deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering system with various substrate bias duty cycle. The tribological and corrosion behaviors of the multilayer films in Hank's solution were evaluated by a ball-on-disk tribometer and an electrochemical workshop. The duty cycle has a significant effect on the bonding structure, and mechanical and tribological properties of the films. The polarization resistance of the films on Ti alloy is approximately ten times more than that of Ti6Al4V which indicates that higher corrosion resistance can be achieved in Hank's solution at 37 °C. However, the polarization resistance and corrosion current do not change so much with the variation of duty cycle, implying that its influence on corrosion behavior of these a-C/a-C:Ti multilayer films is not so obvious. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nitride (CN x ) films were deposited by direct current magnetron sputtering at different N2 fractions and a substrate temperature of 450°C. The composition and microstructure of CN x films were investigated by high resolution transmission electron microscopy, X-ray absorption near-edge spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The CN x films change from amorphous to fullerene-like nanostructure as the N2 fraction is ranged from 0.05 to 0.1, and then to nitridized graphite nanocrystals in amorphous matrix at pure N2, and the curvature of the basal planes decreases with the increase of N content in CN x films. Meanwhile, the structural analysis provides the identification of spectral signatures related with the formation and promotion of FL arrangements, and the formation of C-sp3 sites has been generally considered as the cross-linking path in fullerene-like CN x . Their mechanical and tribological properties were also investigated in detail, aiming at illustrating excellent mechanical, friction and wear behaviours of the fullerene-like CN x film with respect to its high hardness and elastic recovery and less dependence on humidity and oxygen as compared with the amorphous CN x film. [ABSTRACT FROM AUTHOR]

Abstract: Self-supported nickel-coated NiO arrays are prepared by chemical bath deposition of NiO flake arrays followed by magnetron sputtering of nickel nanoparticles. The effect of sputtering time, namely, coverage of nickel nanoparticles, on the lithium storage performance of Ni-coated NiO array electrode is investigated. It is found that the optimum sputtering time is 60s, and such electrode delivers a reversible capacity of 455, 316 and 187mAhg−1 at a current density of 2, 4 and 7.18Ag−1, respectively, higher than the bare NiO array electrode. The deposited nickel nanoparticles keep the NiO active particles electrically connected and thus improve the electronic conductivity, and also stabilize the flake microstructure during cycling, resulting in the increase in reversible capacity and rate capability. The Ni-coated NiO array electrode, however, is still suffered from a large voltage hysteresis, indicating that the enhanced electronic conductivity is not effective on decreasing this hysteresis. [Copyright &y& Elsevier]

Abstract: Titanium incorporated amorphous carbon nitride films were deposited by direct current magnetron sputtering. The films change from amorphous to nanocomposite structure, the relative fraction of sp 3 C–N bonding decreases significantly from 2.17 to 1.64 with the increase of Ti content from 2.7at.% to 12.3 at.%. For the films with high Ti content, the nanocrystalline TiN embedded in a-CN x matrix, while principally TiN did not appear to be well formed for the film containing low Ti content. Potentiodynamic polarization, in vitro human osteoblasts and murine fibroblast cell adhesion tests were employed to assess the corrosion performances of Ti6Al4V alloy coated with the films in Tyrode''s solution, and the biocompatibility of Ti-incorporated a-CN x films, respectively. Titanium incorporation increases the corrosion resistance of a-CN x films, and the higher corrosion potential and lower corrosion current density are observed for the alloy coated with the film containing lower Ti content. The high osteoblast adhesion and activation demonstrate the enhanced biocompatibility of Ti alloy coated with Ti-incorporated a-CN x films. The improved biocompatibility in biological environment is attributed to structural change after titanium introduction. [Copyright &y& Elsevier]

Abstract: TiCN nanocomposite films are prepared by direct current magnetron sputtering from Tid target under different nitrogen flow rates. The composition, morphology and microstructure of the nanocomposite films are characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy. Hardness and tribological properties are tested by nanoindentation measurement and ball-on-disk tribometer, respectively. With the increase of nitrogen flow ranging from 0 to 30sccm at a work pressure of 0.3Pa, both crystallinity and sp2 carbon content in the TiCN films increase. In addition, the ratio of TiN to Ti(C, N) increases as the nitrogen flow rate increases. The friction coefficient and wear rate could be greatly reduced due to the increase of sp2 carbon and better toughness in the composite films. TiCN nanocomposite film with high hardness and good wear resistance is obtained under a nitrogen flow rate of 30sccm. [Copyright &y& Elsevier]

Abstract: Carbon nitride (CN x /CN x ) multilayers with sequential sp3-rich and sp2-rich layers were deposited on c-Si substrate by direct current magnetron sputtering. The composition, microstructure and morphology of the films were investigated by the X-ray photoelectron spectroscopy and transmission electron microscopy. In the films, the sp3 C–N rich and the sp2 C–N rich layers exhibit amorphous feature and graphite-like structure, respectively, and the multilayered structure is continuous over relatively well defined and smooth layer interfaces. The mechanical properties of the films were measured by the nanoindentation and nanoscratch tests. The multilayer films showed lower compressive stress and higher hardness than their monolayer components. Meanwhile, the a-CN x multilayer film with a bilayer period of 60nm exhibited the improved mechanical properties, and the lowest friction coefficient and the highest wear resistance. [Copyright &y& Elsevier]