Graphene/Ni（110） has been studied by time-resolved X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure. The C ls core level shows a splitting typical of periodically rippled interfaces. Th...Graphene/Ni（110） has been studied by time-resolved X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure. The C ls core level shows a splitting typical of periodically rippled interfaces. The analysis of the C K-edge reveals that the interface states previously observed for graphene/Ni（111） are suppressed in graphene/Ni（110）. This suppression is due to the reduced hybridization of the Dirac-cone electrons in graphene with the d-bands of the （110）-oriented nickel contacts. Our results show that, contrary to commensurate growth of graphene on Ni（111）, epitaxially grown graphene on Ni（110） behaves as a quasi-freestanding sheet, as the lattice mismatch gives rise to a moir6 reconstruction.展开更多
In this work,the electrochemical behaviors of SAM2X5 Fe-based amorphous alloy coating and hard chromium coating were comparatively studied in 3.5 wt% NaCl solution.In comparison with the hard chromium coating,the SAM2...In this work,the electrochemical behaviors of SAM2X5 Fe-based amorphous alloy coating and hard chromium coating were comparatively studied in 3.5 wt% NaCl solution.In comparison with the hard chromium coating,the SAM2X5 coating exhibited a wider and stable passive region with lower passive current density in the potentiodynamic polarization and showed a considerably lower current density at different anodic potentials in the potentiostatic polarization.In order to understand the passivation mechanism of the Fe-based amorphous coating,the components of the passive films formed at various polarization potentials were examined by X-ray photoelectron spectroscopy.The synergistic effect of Mo,W,Mn and Cr in the passive films was systemically analyzed.It has been revealed that Mo and W facilitate the formation of compact and stable Cr2O3 passive film at lower potentials,and the substantial enrichment of Mn in the passive film enhances the passivation ability at relatively higher potentials.The deep understanding of the passivation characteristics in multicomponent alloy systems could provide a guide for the design of corrosion-resistant amorphous alloy coatings for engineering applications.展开更多
In this study, the corrosion behavior of Ni47Ti49Co4 shape memory alloy（SMA） was investigated in simulated saliva solution with the binary alloy Ni（51）Ti49 as a reference. The surface morphology and the chemical c...In this study, the corrosion behavior of Ni47Ti49Co4 shape memory alloy（SMA） was investigated in simulated saliva solution with the binary alloy Ni（51）Ti49 as a reference. The surface morphology and the chemical composition of the oxide films were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy before and after immersion in the test solutions, respectively. The results showed that the ternary alloy was less affected by the test solution,owning to the formation of passive layer composed mainly of the oxides of titanium and cobalt in several oxidation states.Cyclic voltammetry, electrochemical impedance spectroscopy and potentiodynamic polarization measurements affirmed that the passive oxide film significantly improved the corrosion resistance of Ni47Ti49Co4 SMAs as demonstrated by the smaller corrosion current density, larger resistance and smaller capacitance. Consequently, alloying with cobalt, which has paramount importance in enhancing the passive layer, expands the use of Ni47Ti49Co4 SMAs in dental work as new nitinol alloys with high corrosion resistances.展开更多
文摘Graphene/Ni（110） has been studied by time-resolved X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure. The C ls core level shows a splitting typical of periodically rippled interfaces. The analysis of the C K-edge reveals that the interface states previously observed for graphene/Ni（111） are suppressed in graphene/Ni（110）. This suppression is due to the reduced hybridization of the Dirac-cone electrons in graphene with the d-bands of the （110）-oriented nickel contacts. Our results show that, contrary to commensurate growth of graphene on Ni（111）, epitaxially grown graphene on Ni（110） behaves as a quasi-freestanding sheet, as the lattice mismatch gives rise to a moir6 reconstruction.
基金supported by the National Natural Science Foundation of China (Nos. 51471166, 51131006 and 51171119)the College Youth Scholar Fostering Program of Liaoning Province (No. LJQ2014015)
文摘In this work,the electrochemical behaviors of SAM2X5 Fe-based amorphous alloy coating and hard chromium coating were comparatively studied in 3.5 wt% NaCl solution.In comparison with the hard chromium coating,the SAM2X5 coating exhibited a wider and stable passive region with lower passive current density in the potentiodynamic polarization and showed a considerably lower current density at different anodic potentials in the potentiostatic polarization.In order to understand the passivation mechanism of the Fe-based amorphous coating,the components of the passive films formed at various polarization potentials were examined by X-ray photoelectron spectroscopy.The synergistic effect of Mo,W,Mn and Cr in the passive films was systemically analyzed.It has been revealed that Mo and W facilitate the formation of compact and stable Cr2O3 passive film at lower potentials,and the substantial enrichment of Mn in the passive film enhances the passivation ability at relatively higher potentials.The deep understanding of the passivation characteristics in multicomponent alloy systems could provide a guide for the design of corrosion-resistant amorphous alloy coatings for engineering applications.
基金the financial support of Chemistry Department (Taif University, Saudi Arabia)
文摘In this study, the corrosion behavior of Ni47Ti49Co4 shape memory alloy（SMA） was investigated in simulated saliva solution with the binary alloy Ni（51）Ti49 as a reference. The surface morphology and the chemical composition of the oxide films were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy before and after immersion in the test solutions, respectively. The results showed that the ternary alloy was less affected by the test solution,owning to the formation of passive layer composed mainly of the oxides of titanium and cobalt in several oxidation states.Cyclic voltammetry, electrochemical impedance spectroscopy and potentiodynamic polarization measurements affirmed that the passive oxide film significantly improved the corrosion resistance of Ni47Ti49Co4 SMAs as demonstrated by the smaller corrosion current density, larger resistance and smaller capacitance. Consequently, alloying with cobalt, which has paramount importance in enhancing the passive layer, expands the use of Ni47Ti49Co4 SMAs in dental work as new nitinol alloys with high corrosion resistances.
