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Li Y.-G.,Taiyuan University of Technology | Wei Y.-H.,Taiyuan University of Technology | Wei Y.-H.,Lvliang College | Hou L.-F.,Taiyuan University of Technology | And 2 more authors.
Surface Engineering | Year: 2014

An erbium modified Mg17Al12 based coating was fabricated by hot press sintering on as extruded AZ61 Mg alloy. The Er modified coating was composed of Mg17Al12 and Al3Er phases. As a result of the presence of the dispersed Al3Er phase, the coating had a greater microhardness than Mg17Al12. Thermal effects of sintering at 400uC for 1 h caused no obvious deterioration in the wear resistance of the AZ61 Mg matrix. Electrochemical and wear resistance tests showed that the Er modified Mg17Al12 based coating had a lower corrosion current density and a lower friction coefficient than Mg17Al12, the AZ61 Mg matrix and a thermal diffusion coating (TDC). The superior wear resistance of the sintered coating resulted from the hard Al3Er phase. The corrosion resistance of the sintered coating was better than that of the TDC as a result of suppression of hydrogen evolution by the rare earth metal Er. © 2014 Institute of Materials, Minerals and Mining.

Li Y.-G.,Taiyuan University of Technology | Wei Y.-H.,Taiyuan University of Technology | Wei Y.-H.,Lvliang College | Hou L.-F.,Taiyuan University of Technology | Han P.-J.,Taiyuan University of Technology
Corrosion Science | Year: 2013

This study investigates the atmospheric corrosion behaviour of ingot and as-extruded AM60 Mg alloys in a polluted city. The corrosion rate of the ingot samples was higher than that of the extruded samples. The size of dust particle conglomerates adsorbed on the sample surfaces was related to the pit sizes. The main corrosion products of both alloys included MgSO4·6H2O and MgSO3·6H2O. The extruded samples had more homogeneous structures and less second-phase contents compared with the ingot samples. As a result, the corrosion films formed on the extruded samples had better protective effects than those formed on the ingot samples. © 2012 Elsevier Ltd.

Wei H.,Taiyuan University of Technology | Wei Y.-H.,Taiyuan University of Technology | Wei Y.-H.,Lvliang College | Hou L.-F.,Taiyuan University of Technology
Gongneng Cailiao/Journal of Functional Materials | Year: 2015

Copper-titanium alloys are a kind of age hardening alloys with high strength and good electrical conductivity performance. The phase transition process of copper-titanium alloys was illustrated in detail in this paper and the research status of copper-titanium alloys were described, that is, both aging in hydrogen atmosphere and prior-deformation combined with aging treatment can improve the performance, such as electrical conductivity and strength. It is pointed out that the influence of grain boundary on performance and the effect of plastic deformation on phase transition are still not clear. Prior-deformation combined with aging treatment will be an attractive area of research in the future. ©, 2015, Journal of Functional Materials. All right reserved.

Ren X.,Taiyuan University of Technology | Guo C.,Taiyuan University of Technology | Xu L.,Shandong University | Li T.,Taiyuan University of Technology | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Three-dimensional (3D) hierarchical nanostructures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to the synergistic combination of the advantages of both nanostructures and microstructures. In this study, the honeycomb-like mesoporous NiO microspheres as promising cathode materials for supercapacitors have been achieved using a hydrothermal reaction, followed by an annealing process. The electrochemical tests demonstrate the highest specific capacitance of 1250 F g-1 at 1 A g-1. Even at 5 A g-1, a specific capacitance of 945 F g-1 with 88.4% retention after 3500 cycles was obtained. In addition, the 3D porous graphene (reduced graphene oxide, rGO) has been prepared as an anode material for supercapacitors, which displays a good capacitance performance of 302 F g-1 at 1 A g-1. An asymmetric supercapacitor has been successfully fabricated based on the honeycomb-like NiO and rGO. The asymmetric supercapacitor achieves a remarkable performance with a specific capacitance of 74.4 F g-1, an energy density of 23.25 Wh kg-1, and a power density of 9.3 kW kg-1, which is able to light up a light-emitting diode. © 2015 American Chemical Society.

Li Y.,Taiyuan University of Technology | Wei Y.,Taiyuan University of Technology | Wei Y.,Lvliang College | Hou L.,Taiyuan University of Technology | And 2 more authors.
Journal of Rare Earths | Year: 2014

The effect of the rare earth element Er on the microstructures and properties of Mg-Al intermetallic were studied in this experiment. Metallographic and X-ray diffraction (XRD) results showed that the microstructures of Mg-Al-Er alloys varied with Er content. The Mg-44Al-0.5Er and Mg-43.8Al-1.0Er alloys were both composed of Mg17Al12 matrix and Al3Er phase, whereas Mg-43Al-3.0Er and Mg-42Al-5.0Er were composed of Mg17Al12 matrix, Al3Er phase, and Mg-Mg17Al12 eutectic. The Mg-42Al- 5.0Er alloy showed the highest microhardness, and the values remained nearly stable as Er content increased from 1.0 wt.% to 5.0 wt.%. The dispersed second phase Al3Er caused the grain refinement of the Mg-Al-Er alloy, which was the main reason for the improvement in microhardness. The corrosion resistance of the Er-containing alloys initially increased and then decreased with increasing Er content. All the Er-containing alloys had the ability to suppress hydrogen evolution, which was the main reason for the higher corrosion resistance of the modified alloys than that of the Mg-44.3Al alloy. Considering the higher hardness and dispersity of the Al3Er phase, Mg-43.8Al-1.0Er exhibited higher wear resistance than the as-cast Mg-44.3Al alloy. © 2014 The Chinese Society of Rare Earths.

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