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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]

Graphical abstract Highlights • A 3D network GPE composed of PVDF-HFP and PETT-Ester is successfully fabricated. • The GPE exhibits a wide electrochemical window of 5.05 V (vs. Li/Li+). • The GPE effectively suppresses the extension of lithium dendrite. • The Li/GPE/S cell shows a high specific capacity retention. Abstract A UV-light polymerized three-dimensional (3D) network gel polymer electrolyte (GPE) is designed and fabricated for solid-state lithium-sulfur (Li-S) batteries. The GPE exhibits wide electrochemical window up to 5.05 V (vs. Li+/Li), outstanding thermostability and mechanical property. Besides, the GPE effectively suppresses the extension of lithium dendrite and the electron-donating groups in GPE inhibit the shuttle of lithium polysulfides. The assembled solid-state Li-S batteries with the 3D network GPE show high specific capacity retention of 69.1% after 300 cycles at 0.5 C. With the consideration of these, the GPE in this report undoubtedly provides an effective technique to design high performance solid-state Li-S batteries. [ABSTRACT FROM AUTHOR]

Abstract: Thick a-C/a-C:Ti multilayer films with bilayer periods of 12–70nm were deposited on Ti6Al4V alloy substrate by means of closed field unbalance magnetron sputtering. The morphology and microstructure of the multilayer films were investigated by scanning electron microscopy, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Nanocrystalline TiC was distributed in the a-C:Ti layer and at the interface between the two adjacent layers. The mechanical and tribological properties were evaluated by Rockwell and scratch tests, a nanoindentor and a ball-on-disk tribometer. The multilayer film with a bilayer period of 12nm showed the highest adhesion strength, hardness (26GPa) and elastic modulus (232GPa); it also had the lowest average coefficient of friction (0.09) and a wear rate of 8.06×10−17 m3 N−1 m−1. [Copyright &y& Elsevier]