Time filter

Source Type

Guo T.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Guo T.,Key Laboratory of Non ferrous Metal Alloys and Processing Ministry of Education of China | Zhang D.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Hui Z.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | And 2 more authors.
Advanced Materials Research | Year: 2012

0.04C-16Cr and 0.04C-16Cr containing 26ppm B ferritic stainless steels were smelted by using a vacuum induction furnace. Then 65% boiling nitric acid method and the electrochemical potentiokinetic reactivation method (EPR) were used to research their intergranular corrosion sensitivity. Meanwhile, electrochemical test method (Tafel polarization curve method, the anode circular polarization curve method) and chemical immersion method were used to research their pitting corrosion resistance. The results showed that the corrosion rate of 0.04 C-16Cr stainless steel containing 26ppm B in 65% boiling nitric acid is lower than that of 0.04 C-16Cr stainless steel. The reactivation rate of 0.04C-16Cr containing 26ppm B in dilute sulphuric acid medium significantly reduced compared with that of 0.04C-16Cr. The pitting corrosion potential, self-corrosion potential and the value of (Eb-Ep) of the stainless steel containing with 26ppm B in chlorideions medium reduced, while the corrosion rate increased compared with the stainless steel without B addition. It indicates that trace boron addition improves the intergranular corrosion resistance and repair ability of the passive film of the 0.04C-16Cr ferritic stainless steel after pitting corrosion process in chloride ions medium, but it also promotes the pitting corrosion tendency of the steel. Besides, introduction B to 0.04C-16Cr ferritic stainless steel reduces the steel's corrosion resistance in active dissolved zone and promotes its intergranular corrosion tendency in chloride ions medium. The electrochemical characteristics of local corrosion are consistent with the results of chemical immersion test.


Dai J.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Dai J.,Lanzhou University of Technology | Chen D.,Lanzhou University of Technology | Li Q.,Yibin University
Physica B: Condensed Matter | Year: 2014

The structural and electronic properties of N, P, As and Sb doped (9.0) single-walled SiC nanotubes (SWSiCNTs) are investigated by the first-principle theory. The calculated results indicated that one P, As or Sb atom substituted for one C atom, which could be considered as n-type semiconductors. When one N, P, As or Sb replace one Si atom, the model shows the character of semi-metallic, n-type semiconductor, p-type semiconductor respectively. These results indicated that with the addition of atomic radius and reduction of electronegativity, dopant of VA elements will bring bizarre change of electronic properties. These results are expected to give valuable information in building nanoscale electronic devices. © 2014 Elsevier B.V.


Dai J.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Dai J.,Lanzhou University of Technology | Meng C.,Lanzhou University of Technology | Li Q.,Yibin University
Physica B: Condensed Matter | Year: 2013

The ferromagnetic properties of Zn0.875Co0.125O and Zn0.875(Co0.5Mn0.5)0.125O are investigated using total energy of plane wave and ultrasoft pseudopotentials method based on the density functional theory (DFT). The results show that Zn0.875Co0.125O and cobalt (Co) and manganese (Mn) codoped ZnO-based dilute magnetic semiconductors (DMSs) are of the ferromagnetic order, and the ferromagnetism mostly comes from interaction of spin-polarized oxygen atoms, zinc atoms and transition metals. Meanwhile, it is also found that the magnetic moments are mostly contributed by the spin-polarized oxygen atoms and transition metals. In addition, the electron sharing for the 3d states of transition metals (Co, Mn) and 2p states of O atoms is exacerbated as compared to pure ZnO and Co doped ZnO, helping to obtain p-type ZnO. These results indicate that Co and Mn codoped ZnO are promising magneto-electronic materials and they can be used for nanoscale spintronics device material. © 2012 Elsevier B.V.


Wang Q.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Li X.,Lanzhou University of Technology | Nie W.,Lanzhou University of Technology | Xia Y.,Lanzhou University of Technology | Dai J.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials
Advanced Materials Research | Year: 2010

The ZnO/TiO2 composite films were deposited over glass using spin coating technique by sol-gel process. Single-walled carbon nanotubes (SWNTs) were used to modify the ZnO/TiO2 films successfully in this paper. The structure and composition of the ZnO/TiO2 composite and SWNTs doped ZnO/TiO2 composite were characterized by X-ray diffraction (XRD). The morphology of samples was characterized by scanning electron microscopy (SEM). The photocatalytic activity was investigated by photocatalytic degradation of aqueous methyl orange under ultraviolet (UV) radiation. The UV-vis absorption spectra of the ZnO/TiO2 films and SWNTs doped ZnO/TiO2 films in the wavelength region 200∼800 nm were obtained. The results indicate that the SWNTs addition can decrease the grain size of ZnO/TiO2, which can enhance the photocatalytic activity. UV-vis absorption spectra of SWNTs-ZnO/TiO2 showed obvious blue shifts compared with ZnO/TiO2. The optimal amount of doping SWNTs is 1% according to this research. The enhanced mechanism of the SWNTs for the photocatalytic activity in ZnO/TiO2 films was analyzed in this article. © (2010) Trans Tech Publications.


Dai J.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials | Dai J.,Lanzhou University of Technology | Mu X.,Lanzhou University of Technology | Chen X.,Lanzhou University of Technology | And 2 more authors.
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2011

The field emission performances of normal-gate cold cathode, which is composed of different multi-wall carbon nanotubes (MWCNTs) bundles array are calculated. The device parameters such as the arrangement of bundles, array density, gate location, gate voltage, anode voltages and anodecathode distance affect the field emission properties, which is discussed in detail. The results reveal that the hexagon bundles array needs a lower threshold voltage than square array to reach high field enhancement factor and large emission current density. The emission current density is two orders larger than that of the oxide emitter. The optimal bundles array densities of hexagon and square array to get field enhancement factor are 0.0063 and 0.00375 μm-2, respectively. Meanwhile, the field emission performances are impacted critically by gate location and gate voltage. Field emission properties changed little while the anodecathode distance varies within tens of micrometers, which increases the process-friendliness of CNTs field emission devices.© 2011 Elsevier B.V. All rights reserved.


Wang Q.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Zhang X.,Lanzhou University of Technology | Huo X.,Lanzhou University of Technology | Zhang R.,Lanzhou University of Technology | Da J.,Lanzhou University of Technology
Advanced Materials Research | Year: 2011

Nanocrystalline ZnO and Zn2TiO4 porous film electrodes were prepared by sol-gel method and spin coating method, and the nanocrystalline porous films were characterized by XRD and SEM. Using ZnPc dye and PbS quantum dots as sensitizers. The nanocrystalline film electrodes of ZnO series and Zn2TiO4 series were prepared separately, and their absorption characteristics observed by UV-vis spectrophotometer. The results showed that ZnPc dye and PbS quantum dots could well sensitize the film electrodes, and the effect of ZnPc dye and PbS quantum dots composite sensitization was optimal. Then, the solar cells were fabricated. In simulation sunlight, the overall photoelectric conversion efficiency by Zn 2TiO4/Q-PbS/ZnPc electrode increased by 22%, relative to the ZnO/Q-PbS/ZnPc electrode's. © (2011) Trans Tech Publications.


Cao R.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials | Yu J.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials | Chen J.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials | Wang P.,General Motors
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2013

Fusion-brazing of AZ31B magnesium alloy to HDG60 galvanized mild steel sheets was carried out by Cold Metal Transfer (CMT) technique. The optimized weld appearance was obtained by adjusting welding parameters. The bonding mechanism and mechanical properties of welding joints were studied by scanning electron microscope (SEM 6700F) equipped with energy dispersive X-ray spectrometer (EDS), electron probe microanalysis (EPMA), X-Ray analysis and universal tensile testing machine. Based on the experimental results, it was found that satisfied welded joints can be produced between magnesium and galvanized steel sheets. The welded joints were composed of weld metal, brazed interface and fusion zone. The brazed interface between the magnesium weld metal and galvanized steel primarily consisted of Al, Zn, Mg intermetallics and solid solution, such as Mg solid solutions, MgFeAlO4, Al7Zn3 and Mg2Zn11. Zn and Al played key roles in bonding of Mg/steel joints, and Zn had flow effect on the formation of welded joints. During the tensile test of welded joints, the specimens fractured through the fusion zone, and the tensile-shear strength reached 218 MPa.


Guo T.-M.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Guo T.-M.,Key Laboratory of Non ferrous Metal Alloys and Processing | Zhi H.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Nan X.-L.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | And 3 more authors.
Advanced Materials Research | Year: 2013

Four groups of 1Cr17 stainless steel with diffirent wt% of boron (0ppm, 16ppm, 22ppm and 28ppm) were smelted by a vacuum induction furnace. Then chemical immersion and electrochemical method (the tafel polarization curve method) were used to investigate their corrosion behavior at different temperature (25 °C, 40 °C) in HCL medium. The results show that after adding Boron elements of the 1Cr17 stainless steel sample, it is obvious that its resistance to general corrosion increases and the resistance to intergranular corrosion weakens; at different temperature (25°C, 40°C)in 10% hydrochloric acid solution medium the Corrosion kinetics law are different, while with B element content increases, the immersion corrosion rate decreases. in the reducing hydrochloric acid solution, sample with boron elements show a good behavior on corrosion resistance. © (2013) Trans Tech Publications, Switzerland.


Zhu L.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials | Ma R.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials | Hou G.-Q.,State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials
Suxing Gongcheng Xuebao/Journal of Plasticity Engineering | Year: 2010

For Cr15Mn9Cu2Ni1N stainless steel slab, the occurrence of strain localization during the hot deformation may cause surface defects. Small specimens were cut from the surface layer and the core of a slab, and tension tests were performed on thermal-mechanical testing machine at 950°C~1150°C. Experimental results show that, with the increase of deformation temperature the strength are decreased and percent elongation increased. Before the occurrence of necking or strain localization, specimen experienced two stages including uniform deformation and necking diffusive deformation, both of which causing deformation zone of specimen to obtain macroscopic uniform appearance. The percent elongation of hot tensile test is mainly dependent on the deformation during the stage of necking diffusion. It is understood that during stage of uniform deformation the inhibition of strain localization is mainly depended on strain hardening; during stage of necking diffusive deformation strain rate hardening played a vital role in obtaining larger macroscopic uniform deformation. With the increase of deformation temperature, particularly as temperature higher than 1100°C, strain rate hardening effect of this steel is strengthened, and the occurrence of necking is postponed, thus bigger percent elongation is obtained.


Liu D.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Liu D.,University of California at San Diego | Ding Y.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | Guo T.,State Key Laboratory of Gansu Advanced Non ferrous Metal Materials | And 4 more authors.
Biomedical Materials (Bristol) | Year: 2014

As one of the most important potential candidate alloys for vascular stent application, Mg-Y-Zr based Mg-4.2wt%Y-2.4wt%Nd-0.6wt%Ce(La)-0.5wt%Zr (WE43) alloys were investigated in combination with the forming processes of micro-tubes with 2.0 mm diameter and 0.1 mm wall thickness. Orthogonal experimental design for alloy composition, vacuum melting ingot, heat treatment, integrated plastic deformation and micro-tube forward extrusion are included in the processing procedures. Significant improvements in both the mechanical properties and corrosion resistance in phosphate buffered saline solution for WE43 alloys were achieved through this processing sequence. The influence of the heat treatment and hot extrusion on in vitro degradation and plasticity was found to be associated with grain size reduction and the redistribution of intermetallic particles within the microstructure. As a result, the mechanical properties and the corrosion resistance of Mg alloys can be improved through fine-grain strengthening and solid-solution strengthening to some extent. © 2014 IOP Publishing Ltd.

Loading State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials collaborators
Loading State Key Laboratory of Gansu Advanced Non Ferrous Metal Materials collaborators