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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.


Zhou X.-L.,Key Laboratory of Nondestructive Test | Zhou X.-L.,Nanchang University | Zhou W.,Nanchang University | Hua X.-Z.,Key Laboratory of Nondestructive Test | And 4 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2010

Oxide scales on a low carbon hot rolled steel strip were formed in atmosphere with different concentration of oxygen at 650°C for 30 min. The corrosion behavior of the hot rolled steel strip with various scales was investigated by means of SEM, XRD, polarization curves and electrochemical impedance spectroscopy (EIS) in 3.5 wt% NaCl solution. When the oxygen concentration equaled 5%, the oxide scale consisted of Fe3O4 and Fe particles, and its thickness was only about 6 μm. When the oxygen concentration was higher than or equal to 10%, the scale was composed of the outer layer of Fe2O3, the intermediate layer of Fe3O4, and the inner layer of Fe3O4 and Fe particles. The scale thickness formed in the atmosphere with oxygen content of 10% was about 15 μm, and the amount of Fe2O3 in the scale was fewer than that in the other scales. When the oxygen concentration was higher than 10%, the scale thickness was about 20 μm, and the amount of Fe2O3 in the scale slightly increased compared with that of the scale formed under the oxygen content of 10%. The order of corrosion resistance of the scales under various oxygen contents from good to poor is as follows: 20%, 10%, 30%, 60%, 5%.


Hua X.Z.,Nanchang Hangkong University | Peng X.Y.,Nanchang Hangkong University | Zhou X.L.,Nanchang Hangkong University | Zhou X.L.,Key Laboratory of Nondestructive Test | Chen Q.J.,Nanchang Hangkong University
Advanced Materials Research | Year: 2011

Effects of hydrogen on machinability involving cutting force, surface roughness and chips morphology of BT25y alloy with semi finish machining were carried out. The microstructures and phase composition of different concentrations were studyed by metallurgical microscopy, transmission electron microscope (TEM), and X-ray diffractions (XRD). The results show that existing a optimum hydrogen concentration (0.20wt.%) for machinability of BT25y alloy in which cutting force decreases 179N and surface roughness reduces about 24%, in addition, chips morphology are transferred from continuous to segmental. The grain refinement, hydride precipitations and thermal conductivity resulting from hydrogen can improve the machinability of BT25y alloy.


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.


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.


Zhou L.X.,Key Laboratory of Nondestructive Test | Zhou L.X.,Nanchang Hangkong University | Zhu M.,Nanchang Hangkong University | Hua Z.X.,Nanchang Hangkong University | And 2 more authors.
Advanced Materials Research | Year: 2011

Various structure scales at the surface of SS400 hot rolled strip were fabricated by heat treatment processes involving different temperatures. A simulation about the effect of various temperatures on the oxide scale structure during the coiling process was carried out. The structure and corrosion behavior of different oxide scales formed at the surface of hot rolled strip were investigated in sodium bisulfite (NaHSO3) solution by scanning electron microscope (SEM), X-ray diffraction (XRD), polarization curves and electrochemical impedance spectroscopy (EIS). The scale prepared at 550 °C is mainly composed of one layer of Fe3O4 phase. The scales prepared at 600 °C and 700 °C consist of the outer thin Fe 2O3 layer and the inner (Fe3O4+Fe particles) layer. The scale prepared at 650 °C is mainly composed of Fe 3O4 phase as well as a spot of Fe2O3 phase. The thickness of scale prepared at 650 °C is observed to be more homogeneous than that of other scales and the bonding between the scale and substrate is found to be very strong. The experimental results clearly reveal that the hot rolled strip with scale prepared at 650 °C exhibits the most excellent corrosion resisting property in 0.01 mol/L NaHSO3 solution. © (2011) Trans Tech Publications, Switzerland.


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.


Zhou X.,Key Laboratory of Nondestructive Test | Zhou X.,Nanchang Hangkong University | Zhu M.,Nanchang Hangkong University | Hua X.,Nanchang Hangkong University | And 3 more authors.
Advanced Materials Research | Year: 2012

Different phase compositions and microstructures of oxide scales were formed on the surface of SS400 hot rolled alloys by employing various heat treatment processes. Cyclic wet-dry immersion corrosion test, electrochemical impedance spectroscopy were used to investigate the corrosion resistance of strips with scales fabricated by different heat treatment processes. The results reveal that difference in the corrosion resistance of the various scales is due to the difference in the grain size of Fe 3O 4 phase. Furthermore, the difference in the corrosion resistance of different oxide phases, exhibited by various scales, also render the strips to give various corrosion behaviors. It is surmised that the strip with oxide scale, which consist of a small mount of the outer layer Fe 2O 3 phase distributed continuously and a large quantity of the inner layer Fe 3O 4 phase with the fine grain size, and possess nice compactness, continuity, integrity in the morphology structure, has the best corrosion resistance.


Zhou X.-L.,Key Laboratory of Nondestructive Test | Zhou X.-L.,Nanchang Hangkong University | Nie L.,Nanchang Hangkong University | Hua X.-Z.,Nanchang Hangkong University | And 4 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2011

Oxide scales on 510L steel were fabricated under different heat treatment temperatures. Section morphology of the various scales on the steel was observed by scanning electron microscopy(SEM) and the structure of the oxide scales was determined by X-ray diffraction(XRD) and transmission electron microscope(TEM). Corrosion behavior of the various scales in 0.01 mol/L NaHSO3 solution was investigated by cyclic wet-dry immersion test, scanning Kelvin probe(SKP) and electrochemical impedance spectroscopy(EIS). The results show that thickness of the oxide scales and micro holes increase with increasing temperature. The thickness of the oxide scale plays a greater role in corrosion resistance in the case of keeping oxide scale continuous and good binding between the oxide scale and substrate. The better corrosion resistance of the oxide scale formed at 580°C is observed and the oxide scales formed at lower temperatures present worse corrosion performance.


Ye Z.-G.,Nanchang University | Zhou X.-L.,Nanchang University | Zhou X.-L.,Key Laboratory of Nondestructive Test | Meng H.-M.,University of Science and Technology Beijing | And 3 more authors.
Advanced Materials Research | Year: 2011

Nanostructured elements, including: manganese-molybdenum (Mn-Mo) oxide, manganese-molybdenum-tungsten (Mn-Mo-W) oxide, manganese-molybdenum-iron (Mn-Mo-Fe) oxide, manganese-molybdenum-cobalt (Mn-Mo-Co) oxide, manganese-vanadium-tungsten (Mn-V-W) oxide, manganese-vanadium-iron (Mn-V-Fe) oxide and manganese-iron (Mn-Fe) oxide, have been anodically deposited onto titanium substrates by employing an iridium dioxide interlayer (Ti/IrO 2 anode). The electrochemical characteristics of the resultant oxide deposits have been investigated by cyclic voltammetry (CV) in an aqueous 0.1 M Na 2SO 4 solution. The voltammetric behaviors of the oxide deposits observed are significantly influenced by the doped elements. Molybdenum doping is found to be advantageous at improving the capacitance characteristics of anodically deposited manganese oxide. Comparatively, iron and vanadium doping are found to be unfavorable. The structure and crystallinity of these deposits have been identified by X-ray diffraction (XRD). The surface morphologies of these oxides were acquired from field emission scanning electron microscopes (FESEM). The high values of electrical parameters for the doped deposits are attributed to the net-like and sponge-like nanostructure, and low crystallinity of the doped manganese oxides. The deposit of Mn-Mo oxides exhibits an excellent capacitive-like behavior, possessing the maximum specific capacitance of 810 F g -1 at a CV scan rate of 5 mV s -1 in aqueous 0.1 M Na 2SO 4 solution. © (2011) Trans Tech Publications.

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