Started in 1985 Semimonthly
ISSN 1005-0302
CN 21-1315/TG
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Current Issue
 28 July 2006, Volume 22 Issue 04 Previous Issue    Next Issue
Research Articles
 Select Electrochemical Performance of Surface-Modified LiMn2O4 Prepared by a Melting Impregnation Method Jian TU, Xinbing ZHAO, Gaoshao CAO, Tiejun ZHU, Dagao ZHUANG, Jiangping TU J. Mater. Sci. Technol., 2006, 22 (04): 433-436.  Abstract   HTML   PDF (843KB) The surface of as-prepared LiMn2O4 was modified with ZnO, Al2O3, CoO and LiCoO2 using a simple nitrate melting impregnation method. Transmission electron microscopy (TEM) studies indicated that oxide nano-particles in the range of 10~50 nm are coated on the surface of the spinel. The surface dified samples show better capacity retention than the unmodified LiMn2O4 spinel at both room temperature and 55℃. Among these samples, the ZnO-modified LiMn2O4 shows the best combination of a high capacity and a low capacity fading rate of 0.036% per cycle at room temperature and 0.064% per cycle at 55℃. The improvement for surface modified LiMn2O4 can be attributed to the inhibition of Mn dissolution and O losses on the surface.
 Select Study on Multiple Electromagnetic Continuous Casting of Aluminum Alloy Zhifeng ZHANG, Jun XUN, Likai SHI J. Mater. Sci. Technol., 2006, 22 (04): 437-440.  Abstract   HTML   PDF (1061KB) To obtain semi-solid Al alloy billet with high quality, an investigation was carried out by imposing a multiple magnetic field from the outside of a copper mold in the continuous casting. AlSi6Mg2 alloy designed for semi-solid metal (SSM) processing was continuously cast through a submerged entry nozzle under various conditions. Effects of multiple magnetic field on meniscus motion, temperature distribution and billet quality were examined. The experimental results showed that meniscus disturbance caused by electromagnetic stirring could be controlled effectively and the surface quality of semi-solid Al alloy billet was improved greatly, and an uniformly fine, globular microstructure across the transverse section of the billet was achieved by optimizing the distribution of multiple magnetic field.
 Select Phase-field Simulation of Microstructural Evolution during Preparation of Semi-solid Metal by Electromagnetic Stirring Method Xiaolu YU, Fuguo LI, Yuanchun REN, Miaoquan LI J. Mater. Sci. Technol., 2006, 22 (04): 441-446.  Abstract   HTML   PDF (292KB) phase-field method to simulate non-dendritic growth during preparation of Al-4Cu-Mg semi-solid alloy by electromagnetic stirring method (EMS method). Several factors such as the disturbance intensity, anisotropy, the thickness of the interface and the ratio of diffusivity in solid and liquid were considered. It is shown that decreasing the thickness of the interface results in more circular outline of particles, and increasing the diffusivity in solid can reduce degree of microsegregation. The disturbance intensity in the model can be connected with current intensity of stator or magnetic induction density impressed. Simulation results show that the larger the disturbance intensity or magnetic induction density, the more globular morphology the original phase in the matrix.
 Select Preparation for Semi-Solid Aluminum Alloy Slurry under Weak Electromagnetic Stirring Conditions Weimin MAO, Yuelong BAI, Guoxing TANG J. Mater. Sci. Technol., 2006, 22 (04): 447-451.  Abstract   HTML   PDF (895KB) The effects of pouring temperature, short electromagnetic stirring with low strength and then soaking treatment on the microstructure of AlSi7Mg alloy were investigated. The results show that if AlSi7Mg alloy is poured at 630 or 650℃ and meanwhile stirred by an electromagnetic field at a low power for a short time, the pouring process can be easily controlled and most solidified primary α-Al grains become spherical and only a few of them are rosette-like. Weak electromagnetic stirring makes the temperature field more homogeneous and makes the primary α-Al grains disperse in a larger region, which leads to the spherical microstructures of primary α-Al grains. When the AlSi7Mg alloy is soaked or reheated at the semisolid state, the primary α-Al grains ripen further and they become more spherical, which is favorable to the semi-solid forming of AlSi7Mg alloy.
 Select Microstructural Changes of Ti-6Al-4V Matrix by the Incorporation of Continuous SiC Fibers Yuechun FU, Nanlin SHI, Dezhi ZHANG, Rui YANG J. Mater. Sci. Technol., 2006, 22 (04): 452-454.  Abstract   HTML   PDF (734KB) In SiC(f)/Ti-6Al-4V composites, the microstructure of the matrix close to the fiber was different from that of the fiber-less material. Microstructure observations show that a layer of fine grains was located adjacent to the fiber, and more dislocations and faults were found in this region. Higher recrystallization nucleation rate due to the undeformed SiC fiber and thermal residual stress induced during cooling from the fabrication temperature caused the microstructural changes of the matrix. Hardness measurement indicates that the matrix in the fiber neighborhood was strengthened, and the strengthening effect decreased with distance away from the fiber.
 Select In-situ Synthesis of Ti3AlC2/TiC-Al2O3 Composite from TiO2-Al-C System Jixin CHEN, Jialin LI, Yanchun ZHOU J. Mater. Sci. Technol., 2006, 22 (04): 455-458.  Abstract   HTML   PDF (2160KB) Ti3AlC2/TiC-Al2O3 composite was synthesized by a combustion reaction in TiO2-Al-C system. The effect of the compositions in raw materials on the products was investigated. T Ti3AlC2/TiC-Al2O3 composite was obtained at the molar ratio of TiO2:Al:C=3.0:5.0~5.1:1.8~2.0. The reaction path for the 3TiO2-5Al-2C system was proposed. Al3Ti, Ti2O3, TiO, and δ-Al2O3 are found to be transitional phases. Finally, Ti3AlC2/TiC-Al2O3 composite forms at ~900℃ of furnace temperature. The measured Vickers hardness, fracture toughness, and flexural strength of the nearly dense sample from 3TiO2-5Al-2C are 13.3±1.1 GPa, 5.8±0.3 MPa•m1/2, and 466±39 MPa, respectively.
 Select Growth Behavior of α Phase in Ti-5.6Al-4.8Sn-2.0Zr-1.0Mo-0.35Si-0.7Nd Titanium Alloy Shangzhou ZHANG, Yuan GAO, Guodong WANG, Yuyin LIU, Rui YANG J. Mater. Sci. Technol., 2006, 22 (04): 459-464.  Abstract   HTML   PDF (1710KB) The thermal stability of the microstructure of a near-α titanium alloy after aging at 750℃ was investigated using optical microscope and transmission electron microscope as well as composition analysis. Aging treatment brings about significant coarsening of grain boundary α and α platelets within the colonies for martensitic microstructure. The observed changes are related to the growth steps or ledges of the interface and lamellar termination presented in the microstructure. The composition analysis of the coarsened $\alpha$ plate is consistent with the growth kinetics. The α Widmanstätten plates were coarsened due to the movement of α/β interface for Widmanstätten microstructure, and the phase boundaries of primary α (αp) phase directly moved into the transformed β for bimodal microstructure.
 Select Improvement of Ductility of Powder Metallurgy Titanium Alloys by Addition of Rare Earth Element Yong LIU, Lifang CHEN, Weifeng WEI, Huiping TANG, Bin LIU, Baiyun HUANG J. Mater. Sci. Technol., 2006, 22 (04): 465-469.  Abstract   HTML   PDF (725KB) Ti-4.5Al-6.0Mo-1.5Fe, Ti-6Al-1Mo-1Fe and Ti-6Al-4V alloys were prepared by blended elemental powder metallurgy (PM) process, and the effects of Nd on the microstructures and mechanical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found out that the addition of Nd increased the density of sintered titanium alloys slightly by a maximum increment of 1% because small amount of liquid phase occurred during sintering. The addition of Nd shows little effect on the improvement of tensile strength, while the elongation is significantly improved. For example, the elongation of Ti-4.5Al-6.0Mo-1.5Fe can be increased from 1% without addition of Nd to 13% at a Nd content of 1.2 wt pct.
 Select Surface Microcracks and Relief Caused by Lamella Sliding during High Temperature Tension of Titanium Alloy with Lamella Structure Feng XU, Geping LI, Mesut VARLIOGLU, Philip NASH, Rui YANG J. Mater. Sci. Technol., 2006, 22 (04): 470-472.  Abstract   HTML   PDF (1137KB) Lateral surface near the fracture of tensile sample was examined by scanning electron microscopy (SEM) before and after oxide film removing. The relationship between surface morphology and microstructure was established. The results show that the microcracks are caused by brittleness rupture of surface oxide films due to α lamellas sliding along α lamella boundaries. And the sliding of aligned α lamellas bring not only microcrack formation but also the raise of colony relative to prior sample surface. A slip model, which depicts the relationship between surface morphology and microstructure, was brought forward to analyze the observation.
 Select Effects of Process Parameters on the Temperature Field in Ti-6Al-4V Alloy Blade Precision Forging Process Yuli LIU, He YANG, Tao GAO, Mei ZHAN J. Mater. Sci. Technol., 2006, 22 (04): 473-477.  Abstract   HTML   PDF (2087KB) Blade precision forging is a high temperature and large plastic deformation process. Process parameters have a great effect on temperature distribution in billet, so in this paper, by taking a Ti-6Al-4V alloy blade with a tenon as an object, the influence of process parameters on the temperature distribution in precision forging process was investigated using 3D coupled thermo-mechanical FEM (finite element method) code developed by the authors. The results obtained illustrate that: (1) the gradient of temperature distribution increases with increasing the deformation degree; (2) with increasing the initial temperature of the billet, the zones of high temperature become larger, and the gradient of temperature distribution hardly has any increase; (3) friction factors have little effect on the distribution of temperature field; (4) with increasing upper die velocity, temperature of the billet increases while the temperature gradient in billet decreases. The results are helpful to the design and optimization of the process parameters in precision forging process of Ti-alloy blade.
 Select Soft-punch Hydro-forming of 304 Stainless Steel Sheet Maosheng LI, Yongnian YAN, Junbin PENG, Rendong WU J. Mater. Sci. Technol., 2006, 22 (04): 478-482.  Abstract   HTML   PDF (3193KB) The process of soft-punch hydro-forming was used to form some workpieces. However, it has not been completely understood until now. In this paper, based on some primary experiments, in which cups have been tried under different working conditions with the soft-punch hydro-forming process, systematical know-how about why the LDR of a metal sheet is different, how working conditions influence qualities of a work-piece, and how the deformation takes place has been achieved when simulations are employed. All these results claim that the cup depth heavily weighs on the cup wall thinning rate, and a satisfied complex part can be achieved when the contacting time between the sheet and the female die is under our control well by a movable slider, which is fixed as the bottom of the female die.
 Select Irregular Characteristics of Bond Interface Formation in Ultrasonic Wire Wedge Bonding Mingyu LI, Hongjun JI, Chunqing WANG, Au Tai KUNG, Han Sur BANG, Hee Seon BANG J. Mater. Sci. Technol., 2006, 22 (04): 483-486.  Abstract   HTML   PDF (1199KB) The mechanism of ultrasonic wire wedge bonding, one of the die/chip interconnection methods, was investigated based on the characteristics of the ultrasonic wire bonding joints. The Al-1%Si wire of 25 μm in diameter was bonded on Au/Ni/Cu pad and the joint cross-section was analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The results indicated that it is irregular for the ultrasonic bond formation, non-welded at the centre but joining well at the periphery, especially at the heel and toe of the joint. Furthermore, the diffusion and/or reaction at the cross-section interface are not clear at C-zone, while there exists a strip layer microstructure at P-zone, and the composition is 78.96 at. pct Al and 14.88 at. pct Ni, close to the Al3Ni intermetallic compound. All these observations are tentatively ascribed to the plastic flow enhanced by ultrasonic vibration and repeated cold deformation driving interdiffusion between Al and Ni at bond interface.
 Select X-ray Photoemission Spectroscopy Studies of the Semiconducting Molybdenum Purple Bronze Bi0.2MoO3 Rui XIONG, Chang LUO, Wufeng TANG, Jing SHI J. Mater. Sci. Technol., 2006, 22 (04): 487-490.  Abstract   HTML   PDF (248KB) The electronic structure of the quasi-two-dimensional (2D) semiconducting molybdenum purple bronze Bi0.2MoO3 was presented by X-ray photoemission spectroscopy. The valence band of Bi0.2MoO3 is made up of Opπ non-bonding level, π and σ bonding bands. The peak at 1.5 eV and the shoulder at 0.5 eV in the forbidden band may be formed from the non-bonding dxy orbitals of some Mo atoms. The O1s core-level spectrum demonstrates the presence of two inequivalent bonds of oxygen ions in Bi0.2MoO3. Bi4f core-level spectrum shows two bonding characters of Bi atoms in bismuth molybdenum single crystal. Mo3d core-level spectrum confirms two kinds of valence states of Molybdenum (Mo+5 and Mo+6). Ar+ ion irradiation induces more significant distortion of MoO6 octahedra.
 Select γ-LiAlO2 Single Crystal Grown by Czochralski Technique and Modified by Vapor Transport Equilibration (VTE) Technique Jun ZOU, Lianhan ZHANG, Jun XU, Shengming ZHOU J. Mater. Sci. Technol., 2006, 22 (04): 491-494.  Abstract   HTML   PDF (506KB) Large-sized (~2 inch, 50.8 mm) γ-LiAlO2 single crystal has been grown by conventional Czochralski (Cz) method, but the crystal has a milky, dendriform center. The samples taken from transparent and milky parts were ground and examined by X-ray diffraction. All diffraction peaks could be indexed in γ-LiAlO2. The crystal quality was characterized by X-ray rocking curve. The full-width at half-maximum (FWHM) values are 116.9 and 132.0~arcsec for transparent and milky parts, respectively. The vapor transport equilibrium (VTE) technique was introduced to modify the crystal quality. After 1000℃/48 h, 1100℃/48 h, 1200℃/48 h VTE processes, the FWHM values dropped to 44.2 and 55.2 arcsec for transparent and milky part, respectively. The optical transmission of transparent part was greatly enhanced from 85% to 90%, and transmission of milky part from 75% to 80% in the range of 190~1900 nm at room temperature. When the VTE temperature was raised to 1300℃, the sample cracked and FWHM values of transparent and milky parts were increased to 55.2 and 80.9 arcsec, respectively. By combining Cz technique with VTE technique, large-sized and high quality γ-LiAlO2 crystal can be obtained.
 Select Effect of Processing Route on the Stability of Aqueous ZrO2 suspensions Xiaoli WANG, Lucun GUO J. Mater. Sci. Technol., 2006, 22 (04): 495-499.  Abstract   HTML   PDF (988KB) The relationship between processing route and suspension stability in ZrO2-H2O-PANH4 system was investigated through rheology study. The work showed that two suspensions with identical PANH4 concentration and final solution condition but prepared by different routes differed greatly in stability. This behavior is attributed to their different distribution state of PANH4 on ZrO2 surface that is determined by the adsorption affinity depending on pH condition in solution. High affinity at pH 5.0 induces a nonuniform distribution of soluble PAA－ (polyacrylicacid) on particle surface, which can flocculate the suspension strongly, while low affinity at pH 9.0 induces an uniform distribution of polymer so that the higher stabilization can be achieved. A simple mathematical model was used to account for the observed results.
 Select Finite Element Analysis of Ceramic Coatings under Spherical Indentation with Metallic Interlayer: Part I Uncracked Coatings Minh-Quy LE, Seock-Sam KIM J. Mater. Sci. Technol., 2006, 22 (04): 500-510.  Abstract   HTML   PDF (5093KB) Spherical indentation of ceramic coatings with metallic interlayer was performed by means of axisymmetric finite element analysis (FEA). Two typical ceramic coatings with relatively high and low elastic modulus deposited on aluminum alloy and carbon steel were considered. Various combinations of indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios were used in the modeling. The effects of the interlayer, the coating and the substrate on the indentation behavior, such as the radial stress distribution along the coating surface as well as the coating interface, and the plastic deformation zone evolution in the substrate were investigated in connection with the above mentioned ratios. The coating cracking dominant modes were also discussed within the context of the peak tensile stresses on the coating surface and on the coating interface.
 Select Electron-beam Treatment of Tungsten-free TiC/NiCr Cermet II: Structural Transformations in the Subsurface Layer Baohai YU, V.E.Ovcharenko, S.G.Psakhie, O.V.Lapshin J. Mater. Sci. Technol., 2006, 22 (04): 511-513.  Abstract   HTML   PDF (326KB) The character of structural changes in the surface layer of titanium carbide (TiC) with Ni-Cr alloy binder was investigated theoretically and experimentally after electron-beam treatment of the material surface. The thermal influence of the electron-beam irradiation on the surface layer microstructure of the composite fine-grained material was mathematically analyzed. Quantitative estimations of the depth of the zone in microstructural phase transformations were carried out. The microstructure and concentration profile of Ti distribution in the metallic binder over the cross section of the surface layer with microstructural phase transformations after electron-pulse treatment of the hard metal surface were experimentally investigated.
 Select Pulse Plating of Copper-ZrB2 Composite Coatings Dongming GUO, Min ZHANG, Zhuji JIN, Renke KANG J. Mater. Sci. Technol., 2006, 22 (04): 514-518.  Abstract   HTML   PDF (1315KB) Copper-zirconium diboride (ZrB2) composite coatings were fabricated using pulse plating technique to acquire a new type of EDM (electro-discharge machining) electrode material. The effects of pulse parameters, i.e., the average current density, the frequency and the duty cycle, on the incorporation of ZrB2 particles in the copper matrix were investigated. The amount of codeposited ZrB2 particles had a maximum at average current density of 3 A/dm2 and increased with decreasing duty cycle as well as current frequency of the pulse current used for deposition. The hardness of the coatings increased with increasing ZrB2 percentage, whereas the incorporation of ZrB2 particles had little effect on the resistivity of the composites.
 Select In-situ TiC Reinforced Composite Coating Produced by Powder Feeding Laser Cladding Sen YANG, Wenjin LIU, Minlin ZHONG J. Mater. Sci. Technol., 2006, 22 (04): 519-525.  Abstract   HTML   PDF (2296KB) A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), and X-ray diffractometry (XRD). The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. The microstructure of the coating was mainly composed of γ-Ni dendrites, a small amount of CrB, Ni3B, M23C6 and dispersed TiC particles. Much more and larger TiC particles formed in the overlapping zone, which led to a slightly higher microhardness of this zone. The maximum microhardness of the coating was about HV0.21200. The effects of the laser processing parameters on the microstructures and properties of coating were also investigated.
 Select Thermoelectric Characterization of (Na1-yMy)1.6Co2O4 (M=K, Ca, Sr) Ying LI, Guiying XU, Maofa JIANG J. Mater. Sci. Technol., 2006, 22 (04): 526-528.  Abstract   HTML   PDF (382KB) Oxide materials NaCo2O4 and (Na1-yMy)1.6Co2O4 (M=K, 0.05≤y≤0.35; M=Ca, Sr, 0.10≤y≤0.40) were prepared by a sol-gel method. Experimental results indicated that the Seebeck coefficient and the Power-factor of Na Co2O4 were improved by doping Ca and Sr but not by K. The Power-factor of NaCo2O4 is in its maximum, 1.68×10-4 W•m-1•K-2 and 11% bigger than that of the original one when the dopant fraction of Ca was 0.1. Doping Sr makes NaCo2O4 have the biggest Power-factor, 1.68×10-4 W•m-1•K-2 that is 50% bigger than the non-doping oxide. The experimental results indicate that suitable dopants and addition amounts could improve the thermoelectric properties of NaCo2O4 greatly.
 Select Nano ZrO2 Particulate-reinforced Lead-Free Solder Composite Jun SHEN, Yongchang LIU, Dongjiang WANG, Houxiu GAO J. Mater. Sci. Technol., 2006, 22 (04): 529-532.  Abstract   HTML   PDF (1354KB) A lead-free solder composite was prepared by adding ZrO2 nanopowders in eutectic Sn-Ag alloy. Microstructural features and microhardness properties of those solders with different ZrO2 nanopowder fraction were examined. Results indicate that the addition of ZrO2 nanopowders reduced the size of β-Sn grains and restrained the formation of bulk Ag3Sn intermetallic compounds (IMCs) due to the adsorption effect of the ZrO2 particles. The Vicker's hardness of the obtained lead-free solder composites fits well with the Hall-Petch relationship. The refinement of β-Sn grains favors to improve the microhardness of composite solders.
 Select Synthesis and photoconductivity of nanosized phthalocyanine Shuguang BIAN, Xianggao LI, Lei SHAO, Jianfeng CHEN J. Mater. Sci. Technol., 2006, 22 (04): 533-535.  Abstract   HTML   PDF (376KB) Functional phthalocyanine (Pc) compounds of H2Pc, TiOPc, FePc and ClAlPc were synthesized with a yield of 46.7%, 91.2%, 37.4% and 34.0%, respectively. Nanosized TiOPc was synthesized via a one-step sol-gel method and effects of surfactant doses, nucleation temperature on TiOPc particle size and photoconductivity were investigated. When m(PEG): m(TiOPc) was 0.1 and nucleation temperature was 0℃, the as-obtained TiOPc had the smallest particle size and largest specific surface area, which were 60~nm and 83 m2/g, respectively. TiOPc synthesized under these conditions also exhibits excellent photoconductivity with charging potential V0, dark decay speed Rd and energy for half-discharging of potential E 1/2 being 1160 V, 30 V/s and 0.6 lx•s, respectively.
 Select Jet Shaping Nanofibers and the Collection of Nanofiber Mats in Electrospinning Xinwei WANG, Jin CAO, Zuming HU, Wanlian PAN, Zhaofeng LIU J. Mater. Sci. Technol., 2006, 22 (04): 536-540.  Abstract   HTML   PDF (484KB) Electrospinning is an effective way to produce nanofibers. The concentration or the corresponding viscosity of the spin solution is one of the most important variables to control the fiber morphology in electrospinning. Jet shaping nanofibers might be divided in two operating modes for different solution viscosity: split thinning and single thinning. From the analysis of jet single thinning, an equation to calculate the velocity of nanofibers depositing on the collector was educed and it was found that the velocity range was very different from the reported result. For the electrospun mats obtained from low solution concentration, the split is observed by scanning electron microscopy (SEM) images. On the other hand, the beads formation in the nanofiber mats can be explained well by jet splitting. The arrangement of nanofibers in the mats is related to the methods of collection, and the cylinder collector gets more ordered mats. This result is proved by so-called break strengths testing and SEM images of the mats obtained from different methods of collection.
 Select Fabrication of ZnO Nanoneedle/nanocolumn Composite Films and Annealing Induced Improvement in Their Microstructural and Photoluminescence Characteristics Dongjiang QIU, Ping YU, Yintu JIANG, Huizhen WU J. Mater. Sci. Technol., 2006, 22 (04): 541-545.  Abstract   HTML   PDF (2648KB) ZnO nanoneedle/nanocolumn (NN/NC) composite films were grown via reactive electron beam evaporation (REBE) in the NH3/H2 gaseous mixture by using polycrystalline ZnO ceramic targets as source materials. The growth was performed at low substrate temperatures (450~500℃) without employing any metallic catalysts. As-prepared samples were then rapidly annealed in O2 ambient at a higher temperature (600℃). Electron microscopic observations revealed the typical composite-structured morphologies of NN/NC/substrate of ZnO nanomaterials grown at 500℃. Such unique morphologies should render potential applications, for instance, as an efficient microwave absorption material utilized in the fabrication of concealed aerostat. In addition, X-ray diffraction and photoluminescence measurements showed remarkable improvement in crystal and optical qualities of ZnO NN/NC composite films after annealing.
 Select Laser-induced Voltage in La0.85Sr0.015MnO3/Fe Heterostructure Kexin JIN, Changle CHEN, Shenggui ZHAO, Yongcang WANG, Zhoumo SONG, Xiao YUAN J. Mater. Sci. Technol., 2006, 22 (04): 546-548.  Abstract   HTML   PDF (1809KB) The La0.85Sr0.015MnO3/Fe heterostructure deposited on Si (100) substrate was prepared by the magnetron sputtering. The laser-induced voltage in the sample and the difference in the voltage signals between the current-in-plane geometry and current-perpendicular-to-plane geometry at 77 K were investigated. This difference can be attributed to the different transport mechanisms.
 Select Photoelectric Properties of Soluble ZnPc-Epoxy Derivative Doped with C60 Jingwei CHEN, Yue SHEN, Jiancheng ZHANG, Feng GU, Jinzhuan ZHU, Yiben XIA J. Mater. Sci. Technol., 2006, 22 (04): 549-551.  Abstract   HTML   PDF (604KB) A kind of soluble phthalocyanine derivative (ZnPc-epoxy derivative) was synthesized, and the influence of C60 on the photoelectric properties of the derivative was studied. The results of ultraviolet-visible (UV-Vis) spectra show that the absorption of the complex is larger than that of the ZnPc-epoxy derivative at B belt. But compared with the derivative, the absorption of the complex decreased at Q belt. The fluorescence spectra show that C60 takes role as annihilation in ZnPc-epoxy derivative. Photo-current tests show that the ZnPc-epoxy derivative-C60 film exhibits increasing photoconductive property.
 Select Mechanical Characterisation of Interface for Steel/Polymer Composite Using Pull-out Test: Shear-Lag and Frictional Analysis Mohamed KHARRAT, Maher DAMMAK, Amine CHARFI J. Mater. Sci. Technol., 2006, 22 (04): 552-558.  Abstract   HTML   PDF (1552KB) Fibre-matrix interface is known to have contribution to the mechanical performance of fibre-reinforced composite by its potential for load transfer between the fibre and the matrix. Such load transfer is of great importance in dentistry when a post is used for fixing a ceramic crown on the tooth. In this study, a pull-out test was carried out to analyse the interfacial properties of a steel fibre embedded in a polyester and epoxy matrices. It was found that the fibre-matrix interface is debonded on the whole embedded length when the fibre stress reached the debonding stress. Then, the fibre stress fell down to the initial extraction stress required to pulling out the debonded fibre from the matrix. Both debonding stress and initial extraction stress initiated a linear increase with the implantation length after the debonding stress reached horizontal asymptotes. To analyse the fibre-matrix load transfer before debonding, an analytical shear-lag model was adopted to in this test conditions. Fitting the experimental results with the analytical model provided the interfacial shear strength. By considering the Coulomb friction at the fibre-matrix interface during the fibre extraction process, an analytical model which considers Poisson's effects on both fibre and matrix, was developed. In this model, knowledge of the initial extraction stress of the fibre provides the residual normal stress at the fibre-matrix interface.
 Select Comparison of the Molecular Interaction Volume Model with the Unified Interaction Parameter Formalism in the Fe-Cr-Ni Liquid Alloys at 1873 K Dongping TAO J. Mater. Sci. Technol., 2006, 22 (04): 559-564.  Abstract   HTML   PDF (1129KB) The molecular interaction volume model (MIVM) for a general ternary system was deduced in detail for further clarifying and understanding its general multicomponent expression. Both MIVM and the unified interaction parameter formalism (UIPF) can be used to predict the activities of solutes and solvents in the Fe-Cr-Ni liquid alloys. But the former employs only the infinite dilute activity coefficients, and the later is not applicable without the dilute binary and ternary interaction parameters. MIVM has a certain physical meaning from the viewpoint of statistical thermodynamics, so it is an alternative for the estimation of activity coefficients of the solutes and solvents in a dilute or finite concentration metal solution where the interaction parameters are absent or their accuracies are questionable.
 Select Devitrification of TeO2-doped Fluoroaluminate Glass Bin TANG, Xinqiang YUAN, Tianfeng XUE, Jiacheng LI, Youyu FAN, Hefang HU J. Mater. Sci. Technol., 2006, 22 (04): 565-568.  Abstract   HTML   PDF (333KB) Crystallization behavior of the glass system AlF3-MgF2-CaF2-SrF2-BaF2-YF3-TeO2 (AMCSBY-TeO2) was studied by the nonisothermal method using differential thermal analysis. The activation energy E and Avrami exponent $n$ were determined by nonisothermal method. It is found that the value of E varies with increasing TeO2 and reaches a minimum at 10~mol~fraction TeO2, while n decreases from 3.65 to 1.78 with the addition of TeO2. X-ray diffraction shows that Ba2Te3O8, MgTe2O5, and SrTeO3 phase formed when the glasses were reheated. The addition of TeO2 changes the crystallization mechanism and improves the stability of the fluoroaluminate glass.
 Select Density Measurement of Liquid Metals Using Dilatometer Lianwen WANG, Qingsong MEI J. Mater. Sci. Technol., 2006, 22 (04): 569-571.  Abstract   HTML   PDF (1455KB) The dilatometer method for density measurement of liquid metals was improved to give a high measurement accuracy with simple operation. The density of liquid tin was measured and the results are in agreement with values in literature. The melting point density of liquid Sn was measured to be 6.966×103 Kg•m-3 and the temperature (T) dependence of the density (ρ) for liquid Sn can be well described by a polynomial equation ρ(T)=7.406-9.94×10-4T+2.12×10-7T2
 Select Effect of Microstructure on Electrorheological Property for Pure TiO2 Particle Material Yanli SHANG, Shuzhen MA, Junran LI, Mingxiu LI, Juan WANG, Shaohua ZHANG J. Mater. Sci. Technol., 2006, 22 (04): 572-576.  Abstract   HTML   PDF (2210KB) Pure titanium dioxide (TiO2) particle materials were prepared by hydrolyzing titanium tetrachloride (TiCl4). The microstructures of these materials were determined by X-ray diffraction (XRD), accelerated surface area and porosimetry apparatus (BET), and transmission electron microscopy (TEM). The TiO2 materials obtained by calcinations under different temperatures distinctly revealed different microstructures in crystal structure type, surface area, pore size, pore volume and grain size. The relationship between the microstructure of the TiO2 materials and their electrorheological (ER) activity was investigated. Anatase titania particles have better ER performance than rutile titania particles. Amorphous TiO2 materials display higher ER activity than the crystalline titania materials. A large pore volume can be more advantageous in improving the ER effect of a particle material.
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