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      20 January 2013, Volume 0 Issue 1 Previous Issue    Next Issue
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    Key Processes and Mechanism for Preparing Graphene by Hummers Method
    REN Xiao-meng, WANG Yuan-sheng, HE Te
    2013, 0 (1): 1-5,44.   DOI: 10.3969/j.issn.1001-4381.2013.01.001
    Abstract ( 2190 ( PDF (1870KB)( 1055 Citation
    Graphene was prepared by the classic Hummers method. By changing reaction temperature, reaction time, oxidant addition and reductant addition, the key processes that influenced the preparation were studied. The result shows that keeping the high temperature stage in the range of 90-100℃ is the most important factor to ensure high yield. In order to improve yield, the low and intermediate temperature stages should be kept close to 0℃ and 30-45℃, and the reaction time should be longer than 30min and 60min respectively. Moreover, excess oxidants is also an important factor.
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    Effect of Different Surface Treatments on Painting Adhesion and Galvanic Corrosion Behavior of Titanium Alloy Ti-6A1-4V
    WU Song-lin, LIU Ming-hui, YI Jun-lan, CHEN Jie, YANG Yong-jin, WANG Zhi-shen
    2013, 0 (1): 6-11.   DOI: 10.3969/j.issn.1001-4381.2013.01.002
    Abstract ( 1008 ( PDF (2241KB)( 503 Citation
    The effect of different surface treatments(pulse current anodizing, direct current anodizing and acid pickling passivating) on painting adhesion and galvanic corrosion behavior of titanium alloy Ti-6Al-4V coupled with aluminum alloy 2024 treated chromic acid anodizing was studied. Result of microstructure and tape adhesion tests shows porous film on the surface of titanium alloy treated by pulse current anodizing can effectively improve its painting adhesion . It was demonstrated by galvanic corrosion test that anodized films on titanium alloy can significantly reduce the susceptibility of galvanic corrosion between titanium alloy and aluminum alloy. Pulse current anodizing process shows better performance than direct current anodizing and acid pickling passivating in application by the results of these comparison.
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    Preparation and Properties of PTFE/PAN Blend Hollow Fiber Membrane
    LI Liang, XIAO Chang-fa, HUANG Qing-lin, HU Xiao-yu
    2013, 0 (1): 12-15,20.   DOI: 10.3969/j.issn.1001-4381.2013.01.003
    Abstract ( 1376 ( PDF (1976KB)( 428 Citation
    Poly(tetrafluoroethylene)(PTFE)/poly(acrylonitrile)(PAN) blend hollow fiber membranes were prepared from the blends of PTFE emulsion and PAN through dry-wet spinning method. The chemical constitutions of hollow fiber membranes before and after sintering were investigated with FT-IR. Meanwhile, TGA was utilized to analyse the thermal stability of hollow fiber membranes. The structure and morphology of hollow fiber membranes at different sintering temperatures were characterized by field emission scanning electronic microscopy (FESEM).Results show that cyclization reaction occurs during the pre-oxidation and sintering process in PAN. Moreover, the trapezoidal structure improves the thermal resistance of hollow fiber membranes; the size of node-fibril structure increases obviously as the raising of sintering temperature, which leads to the enhancement of membrane mechanical strength.
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    Hot Deformation Behavior and Processing Map for New Al-Zn-Mg-Cu Alloy
    TAO Le-xiao, ZANG Jin-xin, ZHANG Kun, CHEN Hui-qin
    2013, 0 (1): 16-20.   DOI: 10.3969/j.issn.1001-4381.2013.01.004
    Abstract ( 1205 ( PDF (2639KB)( 465 Citation
    The hot deformation behavior of a new Al-Zn-Mg-Cu high strength alloy was investigated by hot compression tests conducted on thermo-mechanical simulation experimental method at 300-450℃, strain rate 10-3-10s-1 and 50% height reduction. The processing maps of the alloy were established. Both of temperature and strain rate have a dramatic effect on flow stresses. The flow stress curves of the alloy present the features of steady-state dynamic recovery curve at the test conditions. The results of processing maps and microstructures show that the parameter range of 350-450℃ and 10-3-10-2s-1 is suitable to smaller strain(ε=0.1)casting structure features; and the parameter range of 300-450℃ and 10-3-10-1s-1 is suitable to larger strain(ε=0.5)forging structure features.
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    Preparation and Characterization of Nano-heterojunction CdSe/TiO2 Film
    XUE Jin-bo, LI Xue-fang, LIANG Wei, WANG Hong-xia
    2013, 0 (1): 21-24.   DOI: 10.3969/j.issn.1001-4381.2013.01.005
    Abstract ( 919 ( PDF (1707KB)( 362 Citation
    CdSe thin films were fabricated on ITO glass substrate and TiO2 nanotube arrays by electrochemical method in a three-electrode system in electrolyte containing SeO2, CdCl2?5/2H2O and H2SO4 at room temperature. The crystalline structure and morphology of the composite films prepared under different deposited potentials (-0.6,-0.7,-0.8,-0.9V,vs SCE) were investigated, and the optical properties of the composite films were measured. The results show that the prepared CdSe nanoparticles are agglomerated inhomogeneously. The optical absorption and photoelectric current of composite films are enhanced with the deposited potential increasing. The film deposited under -0.8V exhibits the maximum photoelectric current, but it is easy to peel from the substrate. According to the fastness and photocurrent response of the composite film, the suitable deposition voltage is around -0.7V for obtaining the optimum film.
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    Preparation of Copper Nano-particles and Dispersion Technics in Alcohol
    ZHANG Xiao-min, ZHANG Zhen-zhong, LIN Feng, WEN Yong-peng, LEI Xiao-xu
    2013, 0 (1): 25-29.   DOI: 10.3969/j.issn.1001-4381.2013.01.006
    Abstract ( 921 ( PDF (1919KB)( 418 Citation
    The Cu nano-particles were prepared by direct current arc plasma evaporation method. The crystal structure, chemical composition, particle morphology and particle size distribution were characterized by X-ray diffraction(XRD), X-ray fluorescence analysis(XRF), transmission electron microscopy(TEM), selected area electron diffraction(SAED). The effects of ultrasonic time and surfactant concentration on the dispersing property of Cu nano-powders in alcohol solvent were studied systematically via pH-Zeta value measurement. The mechanism of the dispersion was investigated. The results indicate that the Cu nano-particles prepared by direct current arc plasma evaporation have a high purity of 99.91% (mass fraction), a narrow size distribution, spherical shape, and the crystal structure of the samples is polycrystalline cubic structure. A better dispersion condition of ultrafine Cu powders in alcohol solvent is confirmed as below: OA/HSA (OA-0.5%,HSA-0.5%), the ultrasonic time is 70min, and the pH value is 9.
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    Interface of Continuous Carbon Fiber Reinforced ABS
    HUANG Li, ZHANG Qi-xin, WANG Cheng-zhong
    2013, 0 (1): 30-34.   DOI: 10.3969/j.issn.1001-4381.2013.01.007
    Abstract ( 990 ( PDF (1868KB)( 317 Citation
    Domestic continuous carbon fiber filament and ABS were used to fabricate the thermoplastic composite materials by three processes (common blending, film stack impregnation and solution impregnation). The influence of the preparation parameters on the interface was studied by analysis of mechanical property, thermal property, dynamic visco-elasticity, and morphology of the composites. The results show that the mechanical properties of the composites increase with the increase of carbon fiber content in all three processes, and the highest mechanical properties are obtained with 60% carbon fiber mass fraction, though different percent of mechanical property increase is observed in different processes due to the differences in interface property. The composite by solution impregnation process has a much better wetting ability between fiber and resin, reaches a tensile strength of 1100MPa and an interlaminar shear strength of 71MPa, which increase by about 80% compared with those of the composite by common blending process. The composite by solution impregnation process has a loss tangent only 40%. The improvement of interface leads to the improvement of thermal property.
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    Hydroforming Mechanism of Y-shaped Tube and Influence of Axial Feed Ratio on Forming
    WANG Xin, YU Xin-hong
    2013, 0 (1): 35-39,72.   DOI: 10.3969/j.issn.1001-4381.2013.01.008
    Abstract ( 839 ( PDF (2794KB)( 389 Citation
    Owing to the structure asymmetry of Y-shaped tube, there was a great influence of axial feed ratio on hydroforming. With numerical simulation, based on Dynaform software platform, an elastic-plastic finite element model for Y-shaped tube was established, and the warm hydroforming process of Y-shaped tube by using the model, plastic deformation laws and failure behavior, kinds of defects in forming and effects of axial feed ratio on forming were studied. The results show that after forming the left fillet transition region is the thickest, and the top of the branch is the thinnest; the branch height also increases with the axial feed ratio increasing, and to some extent, it can improve the thinning of the branch, but an excessive axial feed ratio will lead the top of the branch to thinning seriously.
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    Biaxial Fatigue Behavior Under Combined Axial and Torsional Loading for S135 Drill Pipe Steel
    LUO She-ji, ZHAO Kang, WANG Rong
    2013, 0 (1): 40-44.   DOI: 10.3969/j.issn.1001-4381.2013.01.009
    Abstract ( 1253 ( PDF (3813KB)( 265 Citation
    Biaxial fatigue behavior under combined axial and torsional loading for S135 drill pipe steel was investigated by means of fatigue tests and data regression analysis methods, and the fracture surfaces were observed through scanning electron microscopy. The results show that when τa/σeq is 0.7 the fatigue life regulation of S135 drill pipe steel under combined axial and torsional loading can be represented well by the fatigue life equation, which is expressed by equivalent stress of tension-torsion stress amplitude. The fracture surfaces are mainly divided into three regions such as the crack initiation, steady crack propagation and instantaneous fracture. Fatigue cracks mainly initiate at the specimen surface and propagate rapidly in specimen. Fatigue cracks are multiple source and the so-called ridge patterns were formed by connecting the different fatigue source and combined loading. The fracture surfaces are characteristic of river patterns at crack initiation region,the fracture surfaces are characteristic of fatigue striation and rippled patterns at crack propagation region.
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    Characterization and Layer-by-layer Self-assembly of PVA/NCC/PVA
    LIU Zhi-ming, WU Peng, XIE Cheng, WANG Hai-ying, MENG Wei
    2013, 0 (1): 45-51.   DOI: 10.3969/j.issn.1001-4381.2013.01.010
    Abstract ( 1337 ( PDF (3146KB)( 519 Citation
    The composite membrane of polyvinyl alcohol(PVA) / nanocrystalline cellulose(NCC)/ PVA was prepared by layer-by-layer(LBL) self-assembly based on the driving force of hydrogen bonding. The single-phase distribution of NCC and PVA, the NCC lattice arrangement state and the structure of NCC as an interlayer were verified through attenuated total reflection infrared (ATR-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanism hypothesis was proposed to argue the formation process of this composite membrane. Through the measurements of tensile strength, light transmittance and thermal stability, it indicates that the PVA/NCC/PVA composite membrane from LBL self-assembly has high tensile strength, high transmittance and much more thermal stability. Compared to PVA membrane, the tensile strength and light transmittance of the composite membrane improve 46.1% and 5.44%, respectively, as well as the thermal stability increases 13.2℃. This indicates that the PVA/NCC/PVA composite membrane from LBL self-assembly is a good functional membrane.
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    Electromagnetic Shielding Properties of Magnesium and Magnesium Alloys
    ZHANG Zhi-hua, PAN Fu-sheng, CHEN Xian-hua, LIU Juan
    2013, 0 (1): 52-57.   DOI: 10.3969/j.issn.1001-4381.2013.01.011
    Abstract ( 1226 ( PDF (1655KB)( 415 Citation
    The electromagnetic shielding properties of pure magnesium, magnesium alloys and the difference with other metals were investigated by using the coaxial cable method. The results show that electromagnetic shielding property of pure magnesium is great, and those of magnesium alloys vary with the alloy elements. Among magnesium alloys, Mg-Al-Zn based alloys are the best for electromagnetic shielding. The cause of different shielding properties among different materials and the effects of thickness, electric conductivity on electromagnetic shielding property were also discussed.
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    Effects of Microorganism on Corrosion of Zn-Al-Cd Sacrificial Anode in Natural Seawater
    SONG Xiu-xia, ZHANG Jie, YANG Dong-fang, DUAN Ji-zhou
    2013, 0 (1): 58-63.   DOI: 10.3969/j.issn.1001-4381.2013.01.012
    Abstract ( 1062 ( PDF (2016KB)( 394 Citation
    The effects of the sterile seawater and natural seawater on corrosion of Zn-Al-Cd sacrificial anode were investigated by using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and fluorescence microscopy. The results show that the corrosion potential of sample in the sterile seawater is lower than that in the natural seawater at the beginning of experiment, but at the late of experiment, the result is opposite. The EIS results show that the Rct value in the sterile seawater is much smaller than that of anode in natural seawater, which is because in the natural seawater, a layer of biofilm through the metabolic activities of bacteria is formed on the sample surface. The biofilm could prevent the sample from contacting with seawater directly and slow down the corrosion rate. SEM images reveal the presence of localized corrosion morphologies on the sample in the sterile seawater, while in natural seawater, the corrosion is much uniform. Fluorescence microscopy results show that the bacteria uniformly attach to the sample first, and then reunite uneven. About fourteen days later, the local biofilm forms, and it detaches from the sample finally because of the exhaustion of nutrients.
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    High Temperature Thermal Analysis of Basalt Fiber Reinforced Phenolic Composite
    WEI Hua-zhen, ZHANG Qing-hui, LI Jin-wen
    2013, 0 (1): 64-67,84.   DOI: 10.3969/j.issn.1001-4381.2013.01.013
    Abstract ( 1094 ( PDF (876KB)( 494 Citation
    The B7/S157 basalt fiber reinforced phenolic composite and G/S157 glass fiber reinforced phenolic composite were investigated by high temperature thermal analysis, thermodynamic calculation and composition analysis on the high temperature reaction products. The results show that the iron in basalt acts as the catalyst which changes the carbon-silica reaction process, decreases the reaction temperature and improves the reaction endothermic effect. The analysis results of basalt fiber reinforced phenolic composite are different from those of the glass fiber reinforced phenolic composite.
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    Parametric Modeling of Microstructure of WC-Co Cemented Carbides
    WANG Dong, ZHAO Jun, LI An-hai, WANG Ze-ming
    2013, 0 (1): 68-72.   DOI: 10.3969/j.issn.1001-4381.2013.01.014
    Abstract ( 1217 ( PDF (2218KB)( 307 Citation
    In order to realize the property prediction and microstructure optimization of WC-Co cemented carbides, a model based on "random method", which referred to the construction of two-dimensional microstructure model, was established. Some basic parameters of the microstructure of WC-Co, including average grain diameter, major axis and minor axis, centroid, orientation angle and the Co volume fraction, were considered in the model. C++, Matlab, Python are mixed for programming. The model can be obtained in the mixed program, which can be directly applied in the finite element software. The results show that the actual microstructure characteristics of material can be reconstructed, and the parametric model of microstructure is realized. The design parameters agree well with the actual ones, the feasibility of the method and the reliability of the model are proved.
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    Preparation and Corrosion Resistance of Polythiophene Film/Square Wave Oxide Layer of Stainless Steel
    LIANG Cheng-hao, CHEN Wan, HUANG Nai-bao
    2013, 0 (1): 73-78.   DOI: 10.3969/j.issn.1001-4381.2013.01.015
    Abstract ( 1025 ( PDF (1694KB)( 271 Citation
    A bilayer coating was prepared by electrodepositing a polythiophene (PTH) film on the surface of 304 stainless steel treated by alternating-potential-step passivation. Its structure was characterized by FTIR spectroscopy, SEM and AFM. Its corrosion resistance was also evaluated by electrochemical methods. The results indicate that it is feasible to prepare compact, uniform composite film on the surface of square wave passivated 304 stainless steel (304SS). The structure of PTH layer is suggested to be composed of α-α' coupling thiophene units. PTH films owe reversible electrochemical properties. The conductivity of composite film is in 5-10S/cm range. The interfacial shear strength of PTH film is found to be 0.81MPa on 304SS, 4.98MPa on 304SS/AV800 sample, and 5.10MPa on 304SS/AV1020 sample, respectively. The electrochemical properties of composite film in 1M H2SO4 solution show the bilayer could make corrosion potential move positive 0.80V, provide an effective barrier and keep the metal substrate in a passive state during the immersion time. Comparing with 304SS/AV800 sample, 304SS/AV1020 sample has better characteristic of electrochemistry, electricity and interfacial shear strength since PTH film may grow within the pores which formed on the 304 stainless steel surface after square wave passivation.
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    Naphthenic Acid Corrosion Behavior of 20G Steel at High Temperature
    RAO Si-xian, LYU Yun-rong, AI Zhi-bin, PAN Zi-wei, CEN Yu-wan, CHEN Xue-dong
    2013, 0 (1): 79-84.   DOI: 10.3969/j.issn.1001-4381.2013.01.016
    Abstract ( 904 ( PDF (3845KB)( 423 Citation
    High temperature and high flow rate naphthenic acid corrosion(NAC) simulation device was applied to investigate NAC behavior of 20G low carbon steel at various temperatures and flushing angle. The results show that temperature and flushing angle could significantly influence the corrosion rate of 20G steel in naphthenic acid. The influence of flushing angle is related with experiment temperature and flow rate, at 280-320℃ the corrosion rate reaches the peak value, the corrosion rate decreases with temperature when the temperature exceeds 320℃. The corrosion morphology analysis of 20G steel indicates that the perlites in 20G dissolute preferentially. The ferrite corrodes from the grain boundary to intracrystalline only after the perlite dissolutes.
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    Tribological Properties of Electric Brush MoS2-C Combination Plating
    ZHANG Sen, LI Guo-lu, WANG Hai-dou, XU Bin-shi, MA Guo-zheng
    2013, 0 (1): 85-90,96.   DOI: 10.3969/j.issn.1001-4381.2013.01.017
    Abstract ( 1041 ( PDF (4172KB)( 592 Citation
    MoS2-C composite plating with thickness about 100μm was brushed on GCr15 substrate to improve the tribological properties. The surface morphology, composition, structure and microhardness were analyzed by using SEM, XPS and HV-1000.The tribological properties of this composite plating were tested by MSTS-1. The results show that nanoparticles in composite plating reduce the grain size and improve the strength of this plating through effects of dispersion strengthening and fine crystalline strengthening. The combination plating has good tribological properties and the friction coefficient decreases with the increase of sliding velocity and normal load, wear rate of this plating ascends with the increase of load while curves of wear rate do not fluctuate with variation of sliding velocity.
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    Progress of Tribological Modification and Application of Polyetheretherketone
    LI En-zhong, GUO Wei-ling, WANG Hai-dou, XU Bin-shi
    2013, 0 (1): 91-96.   DOI: 10.3969/j.issn.1001-4381.2013.01.018
    Abstract ( 1189 ( PDF (832KB)( 349 Citation
    The properties and the application of polyetheretherketone(PEEK) are briefly reviewed. The modifying technique and the friction and wear behaviors of the modified PEEK are discussed respectively from fiber reinforcing, adding inorganic fillers , blending with polymer and surface modification. The applications of PEEK composite in aviation, automobile and dope industries are summarized. The dispersion of nano-materials and the compatibility of inorganic-organic in the process of PEEK modification are still important issues to be resolved, the reinforcement and simple modification of PEEK are the focus of future research.
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