Time filter

Source Type

Hua X.-Z.,Nanchang Hangkong University | Zhou L.,Nanchang Hangkong University | Cui X.,Nanchang Hangkong University | Zou A.-H.,Nanchang Hangkong University | And 3 more authors.
Physics Procedia | Year: 2013

38CrMoAl nitriding layer had been prepared by plasma electrolytic nitriding under different concentration of ammonia water. The layer structure, surface and phase composition had been analyzed by OM, SEM , XRD, respectively. Deeper analysis about element distribution in layer had been implemented by GDOES. The layer corrosion resistance had been measured by Parstat2273 Electrochemical workstation. microhardness and the wear properties of specimens were also evaluated. The experiment results show that: The nitriding layer consist mainly of Fe2N and Fe3N, the layer thickness is 85±5 to 165±15±μm and the cross-section microhardness of the layer is 650- 1023HV after treated 10min at 220V. When the concentration of ammonia water drops to 40%, FeO is observed in outer-layer. The intensity of the maximum diffraction peak changed with the varying of nitrogen concentration. With the increasing of ammonia water concentration, the thickness of uniform and compact the white layers increases, the diffusion layers consist of needle nitrides and small carbides first increases then decreases, the distance for the biggest microhardness position to the surface increases obviously. After treated at 60% ammonia water, the layer thickness would get 165μm, the diffusion layer reach 114μm, microhardness of the layer reach 1023HV while the substrate hardness remain 310HV. Compared with the treated sample, the untreated wearing weight increase 4.5 times. The corrosion potential had been improved greatly from -523.4mV to -464.1mV. The white layer reaches 52μm while the ammonia water reaches 70. However the diffusion layer is thinner, so the layer thickness decrease gradually. © 2013 The Authors. Published by Elsevier B.V. Source

Zhai T.,Beijing Normal University | Zhai T.,Beijing University of Technology | Shi J.,Beijing Normal University | Chen S.,Beijing Normal University | And 2 more authors.
Applied Physics Express | Year: 2011

We propose a technique for electromagnetic shielding by combining zero-index metamaterials (ZIMs) and electromagnetic interference. Because the electric field inside the ZIMs can be zero, dielectric breakdown may be avoided, and the shield cover can be ultrathin, which may be less than 1% of the operating wavelength. In addition, we propose an energy concentrator made of ZIMs to confine the electromagnetic energy to a small zone based on the intrinsic refractive properties of ZIMs. This property may have potential in waveguiding applications. © 2011 The Japan Society of Applied Physics. Source

Zhou X.-L.,Nanchang Hangkong University | Zhou X.-L.,Key Laboratory of Nondestructive Test | Zhu M.,Nanchang Hangkong University | Yu H.-Y.,Nanchang Hangkong University | And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2011

Different component and structure of scales were formed on the surface of hot rolled strip by different heat treatment processes. Corrosion behavior of the hot rolled strip with different oxide scales in sodium bisulfite solution were investigated by means of SEM, XRD, LRS, cyclic wet-dry immersion corrosion test, electrochemical impedance spectroscopy (EIS) and corrosion potential test. The results show that oxide scales prepared by different heat treatment processes mainly consist of Fe3O4/FeO/Fe, as well as a spot of Fe2O3. The relative content of Fe3O4 in the oxide scale prepared with slow cooling rate is higher than that in the oxide scale prepared by furnace cooling, while the relative content of FeO is lower. The scale prepared with slow cooling rate is dense, continuous and homogeneous in thickness, but the scale prepared by furnace cooling is less dense, with a lot of defects existing in the scale. The strip with scale formed at slow cooling rate exhibits more excellent corrosion resistance compared with that formed by furnace cooling. Source

Ye Z.-G.,Nanchang Hangkong University | Liu H.-Y.,Nanchang Hangkong University | Zhou X.-L.,Nanchang Hangkong University | Zhou X.-L.,Key Laboratory of Nondestructive Test | And 2 more authors.
Gongneng Cailiao/Journal of Functional Materials | Year: 2011

Through using thermal decomposition method to prepare Ti/IrO 2+MnO 2 anodes, studying the effect of water cooling, aircooling, furnace cooling with nitrogen and furance cooling these four cooling ways on the electrocatalytic activity and stability of Ti/IrO 2+MnO 2 anodes. And the study showed that Ti/IrO 2+MnO 2 anodes which was obtained by water cooling have the highest electrocatalytic activity, at the same time its anodic voltammetric charge (q *) can reach to 140 mC/cm 2, however the stability of that anodes were the worst; both the catalytic activity and stability of furnace cooling electrode and nitrogen cold electrode ware fairly bad; air cooling anode have a higher electrocatalytic activity, and its anodic voltammetric charge (q *) can reach to 118 mC/cm 2, as well as its stability was the highest of all the four anodes. From the comprehensive analysis, air cooling way not only can certain the catalytic activity of the anode, also can ensure the anode has the best stability. Source

Zhou X.-L.,Key Laboratory of Nondestructive Test | Zhou X.-L.,Nanchang University | Ye Z.-G.,Nanchang University | Hua X.-Z.,Nanchang University | And 2 more authors.
Journal of Solid State Electrochemistry | Year: 2010

Ti/IrO 2(x)+MnO 2(1-x) anodes have been fabricated by thermal decomposition of a mixed H 2IrCl 6 and Mn(NO 3) 2 hydrosolvent. Cyclic voltammetry (CV) and polarization curve have been utilized to investigate the electrochemical behavior and electrocatalytic activity of Ti/IrO 2(x)+MnO 2(1-x) anodes in 0.5 M NaCl solution (pH=2). Ti/IrO 2+MnO 2 anode with 70 mol% IrO 2 content has the maximum value of q *, indicating that Ti/IrO 2(0.7)+MnO 2(0.3) anode has the most excellent electrocatalytic activity for the synchronal evolution of Cl 2 and O 2 in dilute NaCl solution. Tafel lines displayed two distinct linear regions with one of the slope close to 62 mV dec -1 in the low potential region and the other close to 295 mV dec -1 in the high potential region. Electrochemical impedance spectroscopic is employed to investigate the impedance behavior of Ti/IrO 2(x)+MnO 2(1-x) anodes in 0.5 M NaCl solution. It is observed that as the R ct, R s and R f values for Ti/IrO 2(0.7)+MnO 2(0.3) anode become smaller, electrocatalytic activity of Ti/IrO 2(0.7)+MnO 2(0.3) anode becomes better than that of other Ti/IrO 2+MnO 2 anodes with different compositions. Ti/IrO 2(0.7)+MnO 2(0.3) anode fabricated at 400 °C has been observed to possess the highest service life of 225 h, whereas the accelerated life test is carried out under the anodic current of 2 A cm -2 at the temperature of 50 °C in 0.5 M NaCl solution (pH=2). © 2009 Springer-Verlag. Source

Discover hidden collaborations