2009年, 第19卷, 第01期　刊出日期：2009-01-25

  

• 全选
  |

Structural Materials
• Select
  Effect of sample diameter on primary dendrite spacing of directionally solidified Al-4%Cu alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 1-8.

  摘要 ( )   可视化   收藏

  The relationship between primary dendrite arm spacing and sample diameter was studied during directional solidification for Al-4%Cu (mass fraction) alloy. It is shown that primary dendrite spacing is decreased with the decrease of the sample diameter at given growth rate. By regressing the relationship between primary dendrite arm spacing and the growth rate, the primary dendrite arm spacing complies with 461.76v^−0.53, 417.92v^−0.28 and 415.83v^−0.25 for the sample diameter of 1.8, 3.5 and 7.2 mm, respectively. The primary dendrite spacing, growth rate and thermal gradient for different sample diameters comply with 28.77v^−0.35G^−0.70, 23.17v^−0.35G^−0.70 and 23.84v^−0.35G^−0.70, respectively. They are all consistent with the theoretical model , and b₁/a₁=2. By analyzing the experimental results with classical models, it is shown that KURZ-FISHER model fits for the primary dendrite spacing in smaller sample diameters with weaker thermosolute convection. Whereas TRIVEDI model is suitable for describing primary dendrite arm spacing with a larger diameter (d＞2 mm) where convection should be considered.
• Select
  Comparison of RSM with ANN in predicting tensile strength of friction stir welded AA7039 aluminium alloy joints

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 9-18.

  摘要 ( )   可视化   收藏

  Friction stir welding(FSW) is an innovative solid state joining technique and has been employed in aerospace, rail, automotive and marine industries for joining aluminium, magnesium, zinc and copper alloys. The FSW process parameters such as tool rotational speed, welding speed, axial force, play a major role in deciding the weld quality. Two methods, response surface methodology and artificial neural network were used to predict the tensile strength of friction stir welded AA7039 aluminium alloy. The experiments were conducted based on three factors, three-level, and central composite face centered design with full replications technique, and mathematical model was developed. Sensitivity analysis was carried out to identify critical parameters. The results obtained through response surface methodology were compared with those through artificial neural networks.
• Select
  Effect of melt superheat on microstructure of Al4Fe2Mn1.5 Monel alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 19-25.

  摘要 ( )   可视化   收藏

  The effect of melt superheat on microstructure of Al4Fe2Mn1.5 Monel alloy made by vacuum melting method was studied. The results show that the alloy consists of dendritic γ matrix and γ′ phase, wherein γ′ phase has two morphologies at different melt superheat. One is divorced eutectic γ′ which distributes in the interdendritic area, the other distributes dispersedly in single particle on the dendritic arm and exists in the petalform shape in the transition area between dendritic arm and interdendritic area. With the increase of superheat, the dendrite becomes finer, the primary dendritic arm is melted off and the secondary dendritic arm spacing decreases. The size of γ′ phase distributed on the dendritic arm becomes smaller and the divorced eutectic γ′ phase increases.
• Select
  Joint performance of laser-TIG double-side welded 5A06 aluminum alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 26-31.

  摘要 ( )   可视化   收藏

  The influence of welding parameters on mechanical properties and microstructure of the welds of laser-TIG double-side welded 5A06 aluminum alloy was investigated. The results show that the weld cross-sectional shape has an intimate relation with the mechanical properties and microstructure of the welds. The symmetrical “X” cross-section possesses a relatively higher tensile strength and elongation than the others, about 91% and 58% of those of base metal, respectively. The good weld profiles and free defects are responsible for the improvement of tensile properties. Due to low hardness of the fusion zone, this region is the weakest area in the tensile test and much easier to fracture. The loss of Mg element is responsible for the decrease of mechanical properties of the joints. The microstructure of “X” cross-section has an obvious difference along the direction of weld depth, and that of the “H” cross-section is consistent and coarse.
• Select
  Effect of Sb on microstructure of semi-solid isothermal heat-treated AZ61-0.7Si magnesium alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 32-39.

  摘要 ( )   可视化   收藏

  The microstructure of semi-solid isothermal heat-treated AZ61-0.7Si magnesium alloy was investigated, and compared with that of the Sb-modified AZ61-0.7Si alloy. The results indicate that it is possible to produce the AZ61-0.7Si alloy with a non-dendritic microstructure by semi-solid isothermal heat treatment, and adding 0.4% Sb can accelerate the non-dendritic microstructural evolution of the alloy. After being treated at 580 ℃ for 120 min, the Sb-modified AZ61-0.7Si alloys can obtain a non-dendritic microstructure with a higher liquid content (16%−18%) and finer unmelted primary solid particles (43−53 μm) compared with the alloy without Sb modification. In addition, after being treated at 580 ℃ for 120 min, the Mg₂Si phases in the AZ61-0.7Si alloys with and without Sb modification change from initial Chinese script shape to granule and/or polygon shapes.
• Select
  Microstructure and corrosion behavior of Mg-Sn-Ca alloys after extrusion

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 40-44.

  摘要 ( )   可视化   收藏

  Mg-Sn-Ca alloys promise a reasonable corrosion resistance in combination with good creep resistance, likely due to the presence of Ca_2−xMg_xSn and other phases. The selected alloys with 3% Sn and Ca in the range of 1%−2% have been extruded in order to achieve more homogeneous microstructure compared with the as-cast alloys. Optical microscopy(OM) and X-ray diffraction(XRD) techniques were used to study the microstructure and phases of these alloys. The corrosion behavior of these alloys was investigated by means of salt spray test and potentio-dynamic measurements. The results obtained on the alloys Mg-3Sn (T3), Mg-3Sn-1Ca (TX31), and Mg-3Sn-2Ca (TX32) indicate the presence of the same phases in as-cast and after extrusion, namely Mg₂Sn, Ca_2−xMg_xSn, and Ca_2−xMg_xSn/Mg₂Ca, respectively. However, due to the occurrence of extensive recrystallization in the extrusion process, the grain size has significantly reduced after extrusion. The reduction leads to the improvement of the corrosion resistance after extrusion which is then comparable with the commercial alloy AZ91D.
• Select
  Effect of eutectic phase on damping and mechanical properties of
  as-cast Mg-Ni hypoeutectic alloys

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 45-49.

  摘要 ( )   可视化   收藏

  Dynamic mechanical analysis (DMA) was applied to systematically investigate the low frequency damping properties of as-cast hypoeutectic Mg-Ni alloys. The results show that the as-cast hypoeutectic Mg-Ni alloys exhibit high damping capacities. The strain amplitude dependent damping curve has its own special characteristic, in which the damping is strongly related to the strain amplitude. The effect of the eutectic phase on damping and the mechanical properties of as-cast hypoeutectic Mg-Ni alloys were also discussed in detail.
• Select
  Corrosion action and passivation mechanism of magnesium alloy in
  fluoride solution

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 50-54.

  摘要 ( )   可视化   收藏

  Corrosion action and passive mechanism of magnesium alloy in the fluoride solution were studied by means of scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and electrochemistry methods. The results show that an insoluble MgF₂ film is generated on the surface of magnesium alloy activated in the hydrofluoric acid. And the mass of the deposited MgF₂ film may reach a constant value, when the mass ratio of Mg/F on the magnesium alloy surface is fixed at 11.3׃1. The activated magnesium alloy gains a ‘passivation state’ in a mixture of sulfuric acid and hydrofluoric acid at a volume ratio of less than 1.2. At the same time the mass of magnesium alloy is maintained as a function of the time. When the ratio is above 1.4, the mass of magnesium alloy rapidly decreases. The passive film formed through adsorption of HF₂⁻ (or H₂F₃⁻, H₃F₄⁻) ions by the deposited MgF₂ film can protect the magnesium alloy from corrosion in fluoride solution, but not in non-fluoride solutions. The passive state is maintained for activated magnesium alloy in an acidic sulfuric nickel solution with added fluoride. If fluoride and carbonate are added to the acidic sulfuric nickel solution, a replacement reaction between magnesium alloy and solution takes place.
• Select
  Dynamic recrystallization and texture development during hot deformation of magnesium alloy AZ31

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 55-60.

  摘要 ( )   可视化   收藏

  The dynamic recrystallization(DRX) and texture development, taking place during hot deformation of magnesium alloy AZ31 with a strong wire texture, were studied in compression at 673 K (0.73 T_m). Two kinds of samples were machined parallelly to the extruded and transverse directions of Mg alloy rods. New fine grains are evolved at original grain boundaries corrugated at low strains and develop rapidly in the medium range of strain, finally leading to a roughly full evolution of equiaxial fine grains. Kink bands are evolved at grain boundaries corrugated and also frequently in grain interiors at low strains. The boundary misorientations of kink band increase rapidly with increasing strain and approach a saturation value in high strain. The average size of the regions fragmented by kink band is almost the same as that of new grains evolved in high strain. These characteristics of new grain evolution process are not changed by the orientation of the samples, while the flow behaviors clearly depend on it. It is concluded that new grain evolution can be controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization(DRX). The latter is discussed by comparing with conventional, i.e. discontinuous DRX.
• Select
  Oxidation behavior of oxidation protective coatings for
  C/C-SiC composites at 1 500 ℃

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 61-64.

  摘要 ( )   可视化   收藏

  Porous carbon/carbon preforms were infiltrated with melted silicon to form C/C-SiC composites. Three-layer Si-Mo coating prepared by slurry painting and SiC/Si-Mo multilayer coating prepared by chemical vapor deposition(CVD) alternated with slurry painting were applied on C/C-SiC composites, respectively. The oxidation of three samples at 1 500 ℃ was compared. The results show that the C/C-SiC substrate is distorted quickly. Three-layer Si-Mo coating is out of service soon due to the formation of many bubbles on surface. The mass loss of coated sample is 0.76% after 1 h oxidation. The sample with SiC/Si-Mo multilayer coating gains mass even after 105 h oxidation. SiC/Si-Mo multilayer coating can provide longtime protection for C/C-SiC composites and has excellent thermal shock resistance. This is attributed to the combination of dense SiC layer and porous Si-Mo layer. Dense SiC layer plays the dual role of physical and chemical barrier, and resists the oxidation of porous Si-Mo layer. Porous Si-Mo layer improves the thermal shock resistance of the coating.
• Select
  Influence of thermo hydrogen treatment on
  hot deformation behavior of Ti600 alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 65-71.

  摘要 ( )   可视化   收藏

  Hot compressive deformation of Ti600 alloy after thermo hydrogen treatment (THT) was carried out within hydrogen content range of 0−0.5%, temperature range of 760−920 ℃ and strain rate range of 0.01−10 s⁻¹. The flow stress of Ti600 alloy after THT was obtained under hot deformation condition, and the influence of hydrogen on work-hardening rate (S*), strain energy density (U*), and deformation activation energy (Q) was analysed. The results show that the flow stress of Ti600 alloy decreases remarkably with the increase of hydrogen when the hydrogen content is less than 0.3%. Both S* and U* decrease with the increase of hydrogen when the hydrogen content is less than 0.3%, and when the hydrogen content is more than 0.3%, S* and U* increase with hydrogen addition. The value of Q decreases with the increase of strain at the same hydrogen content. The addition of small quantity of hydrogen leads to an increase of Q at small strain values, and when the strain reaches 0.6, the value of Q decreases gradually with the increase of hydrogen. When the hydrogen content is within the range of 0.1%−0.3%, the flow stress of Ti600 alloy is decreased when being deformed at the temperature range of 760−920 ℃.
• Select
  In-situ dendrite reinforced Dy-based amorphous matrix composites

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 72-77.

  摘要 ( )   可视化   收藏

  In-situ dendritic reinforced Dy-Fe-Al amorphous matrix composites with a diameter of 3 mm were designed and fabricated by conventional Cu-mold casting method. XRD and SEM analyses were conducted to investigate the microstructure, the mechanical properties and the deformation and fracture behaviors of the composites. The forming mechanism and the deformation and fracture mechanism of the composites were discussed. The results indicate that the microstructures of composites consist of metallic glass matrix and α-Dy dendritic phase. The composites exhibit good mechanical properties with compressive fracture strength of 1 063 MPa, which is attributed to the effective bearing-load ability of the α-Dy dendrites and the glassy matrix and the restriction to the expanding of shear bands and cracks of the α-Dy dendrites. The nature of in-situ crystalline phases embedded in the amorphous matrix for in-situ crystallite reinforced Dy-Fe-Al amorphous matrix composites has a more important influence on the mechanical properties, the deformation and fracture behavior of the composites.
Functional Materials
• Select
  Recent progress in criterions for glass forming ability

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 78-84.

  摘要 ( )   可视化   收藏

  The glass-forming ability(GFA) is an important factor in studying metallic glasses. So far, there are several criteria for evaluating the glass-forming ability. For predicting compositions for bulk metallic glasses, however, they show more or less accuracy and versatility for different cases. In this work, four types of criteria for the glass-forming ability are categorized and reviewed: 1) Indicators with characteristic temperatures; 2) Indicators involving structural factors; 3) Indicators based on Miedema’s model; and  4) Indictors based on phase diagram. It is pointed out that a single indicator cannot be used to predict GFA of all the metallic glass systems correctly due to its limited theoretical framework, and the combination of multiple indicators shows more efficiency and accuracy. Though it is still very difficult to develop a universal indicator for GFA, recent indicators seem to be of more reliable physical meaning than those previously suggested.
• Select
  Microstructure and properties of HVOF sprayed Ni-based
  submicron WS₂/CaF₂ self-lubricating composite coating

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 85-92.

  摘要 ( )   可视化   收藏

  Ni-based submicron WS₂/CaF₂ self-lubricating composite coatings were produced on carbon steel substrate by high velocity oxygen fuel(HVOF) spray processing, and the microstructure and mechanical properties of the coatings were investigated. Non-uniform microstructure characterized by some pores and microcracks is observed in the produced composite coatings, which leads to low microhardness value, low adhesive strength and low frictional coefficient. For Ni45-5%CaF₂-10%WS₂ (mass fraction) and Ni45-10%CaF₂-5%WS₂ (mass fraction) coatings, under the test condition of load 40 N and speed 2 m/s, the friction coefficients obtained at room temperature are in the range of 0.35−0.48 and 0.31−0.41, respectively. The friction coefficients of two kinds of coatings increase to 0.4−0.63 and 0.35−0.46, respectively, at the test speed of 1 m/s. And the Ni45-10%CaF₂-5%WS₂ coating presents the minimum friction coefficient of 0.32−0.38 and good anti-wear properties at 400 ℃.
• Select
  Microstructures and properties of cold drawn and
  annealed submicron crystalline Cu-5%Cr alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 93-98.

  摘要 ( )   可视化   收藏

  The microstructures and properties after cold drawing and subsequent annealing of submicron crystalline Cu-5%Cr (mass fraction) alloy were investigated. The results show that, the microstructure of submicron crystalline Cu-5%Cr can be further refined by cold drawing. After cold drawing, the grains of Cu-5%Cr alloy with grain size of 400−500 nm can be refined to be cellular structures and subgrains with size of 100−200 nm. Both strength and ductility of Cu-5%Cr alloy can be enhanced by cold drawing, and the optimal mechanical properties can be achieved with drawing deformation increasing. It is suggested that dislocation glide is still the main mechanism in plastic deformation of submicron crystalline Cu-5%Cr, but grain boundary slide and diffusion may play more and more important roles with drawing deformation increasing. When the cold drawn Cu-5%Cr wires are annealed at 550 ℃, fine recrystal grains with grain size of 200−300 nm can be obtained. Furthermore, there are lots of fine Cr particles precipitated during annealing, by which the recrystallization softening temperatures of the cold drawn Cu-5%Cr wires can be increased to 480−560 ℃. Due to the fact that Cr particles have the effect of restricting Cu grains growth, a favorable structural thermal stability of the submicron crystalline Cu-5%Cr can be achieved, and the submicron grained microstructure can be retained at high temperature annealing.
• Select
  Comparison of thermal shock behaviors between plasma-sprayed
  nanostructured and conventional zirconia thermal barrier coatings

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 99-107.

  摘要 ( )   可视化   收藏

  NiCoCrAlTaY bond coat was deposited on pure nickel substrate by low pressure plasma spraying(LPPS), and ZrO₂-8%Y₂O₃ (mass fraction) nanostructured and ZrO₂-7%Y₂O₃ (mass fraction) conventional thermal barrier coatings(TBCs) were deposited by air plasma spraying(APS). The thermal shock behaviors of the nanostructured and conventional TBCs were investigated by quenching the coating samples in cold water from 1 150, 1 200 and 1 250 ℃, respectively. Scanning electron microscopy(SEM) was used to examine the microstructures of the samples after thermal shock testing. Energy dispersive analysis of X-ray(EDAX) was used to analyze the interface diffusion behavior of the bond coat elements. X-ray diffractometry(XRD) was used to analyze the constituent phases of the samples. Experimental results indicate that the nanostructured TBC is superior to the conventional TBC in thermal shock performance. Both the nanostructured and conventional TBCs fail along the bond coat/substrate interface. The constituent phase of the as-sprayed conventional TBC is diffusionless-transformed tetragonal(t′). However, the constituent phase of the as-sprayed nanostructured TBC is cubic(c). There is a difference in the crystal size at the spalled surfaces of the nanostructured and conventional TBCs. The constituent phases of the spalled surfaces are mainly composed of Ni_2.88Cr_1.12 and oxides of bond coat elements.
• Select
  9R structure in drawn industrial single crystal copper wires

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 108-112.

  摘要 ( )   可视化   收藏

  By using transmission electron microscopy, the microstructures of drawn industrial single crystal copper wires produced by Ohno Continuous Casting(OCC) process were analyzed. The results show that the typical microstructures in the wires mainly include extended planar dislocation boundaries, a small fraction of twins and some dislocation cells sharing boundaries parallel to drawn direction. Besides the typical microstructures, 9R structure configurations were observed in the wires. The formation of 9R polytypes may be caused by the coupled emission of Shockley dislocations from a boundary.
• Select
  Influence of graphite content on sliding wear characteristics of
  CNTs-Ag-G electrical contact materials

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 113-118.

  摘要 ( )   可视化   收藏

  CNTs-Ag-G electrical contact composite material was prepared by means of powder metallurgical method. The influence of the graphite content on sliding wear characteristics of electrical contact levels was examined. In experiments, CNTs content was retained as 1% (mass fraction), and graphite was added at content levels of 8%, 10%, 13%, 15% and 18%, respectively. The results indicate that with the increase of graphite content, the contact resistance of electrical contacts is enhanced to a certain level then remains constant. Friction coefficient decreases gradually with the increase of graphite content. Wear mass loss decreases to the minimum value then increases. With the small content of graphite, the adhesive wear is hindered, which leads to the decrease of wear mass loss, while excessive graphite brings much more worn debris, resulting in the increase of mass loss. It is concluded that wear mass loss reaches the minimum value when the graphite mass fraction is about 13%. Compared with conventional Ag-G contact material, the wear mass loss of CNTs-Ag-G composite is much less due to the obvious increase of hardness and electrical conductivity, decline of friction surface temperature and inhibition of adhesive wear between composites and slip rings.
• Select
  Beneficial effects of Co²⁺ on co-electrodeposited Ni-SiC nanocomposite coating

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 119-124.

  摘要 ( )   可视化   收藏

  Ni-SiC nanocomposites were fabricated by co-electrodeposition of nickel with silicon carbide nanoparticles on the pure nickel substrates from a nickel sulfate bath with and without the addition of Co²⁺. The presence of Co²⁺ in the electrolyte modifies the Ni matrix to Ni-Co solid solution matrix. It helps to refine the grain size of the nanocomposite coating and improves the content of SiC dispersed in the matrix, and consequently results in higher microhardness. The cathodic polarization curves and electrochemical impedance spectroscopy (EIS) at cathodic potential were investigated in the electrolyte with and without Co²⁺. A modified cathodic polarization curve with a positive shift in reduction potential and a smaller capacitive loop of EIS are observed. These are attributed to the strong adsorption of Co²⁺ on the SiC nanoparticles. Consequently, it increases the forces of electrostatic attraction between the SiC nanoparticles and the cathode, which promotes the codeposition of SiC nanoparticles in the matrix.
• Select
  Electrophoretic deposition of titanium/silicon-substituted hydroxyapatite composite coating and its interaction with bovine serum albumin

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 125-130.

  摘要 ( )   可视化   收藏

  Silicon-substituted hydroxyapatite (Ca₁₀(PO₄)_6-x(SiO₄)_x(OH)_2-x, Si-HA) composite coatings on a bioactive titanium substrate were prepared by electrophoretic deposition technique with the addition of triethanolamine (TEA) to enhance the ionization degree of Si-HA suspension. The surface structure was characterized by XRD, SEM, XRF, EDS and FTIR. The bond strength of the coating was investigated. The results show that the depositing thickness and the images of Si-HA coating can be changed with the variation of deposition time. The XRD spectra of Ti/Si-HA coatings show the characteristic diffraction peaks of HA, and the incorporation of silicon changes the lattice parameter of the crystal. The FTIR spectra shows that the most notable effect of silicon substitution is the decrease of intensities of —OH and PO₄³⁻ groups with the silicon contents increasing. XRD and EDS element analyses present that the content of silicon in the coating increases with increasing silicon concentration in the suspension. The bioactive TiO₂ coating formed may improve the bond strength of the coatings. The interaction of Ti/Si-HA coating with BSA is much greater than that of Ti/HA coating, suggesting that the incorporation of silicon in HA is significant to improve the bioactive performance of HA.
• Select
  Effects of deposition parameters on microstructure and thermal conductivity of diamond films deposited by DC arc plasma jet chemical vapor deposition

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 131-137.

  摘要 ( )   可视化   收藏

  The uniform diamond films with 60 mm in diameter were deposited by improved DC arc plasma jet chemical vapor deposition technique. The structure of the film was characterized by scanning electronic microcopy(SEM) and laser Raman spectrometry. The thermal conductivity was measured by a photo thermal deflection technique. The effects of main deposition parameters on microstructure and thermal conductivity of the films were investigated. The results show that high thermal conductivity, 10.0 W/(K∙cm), can be obtained at a CH₄ concentration of 1.5% (volume fraction) and the substrate temperatures of 880−920 ℃ due to the high density and high purity of the film. A low pressure difference between nozzle and vacuum chamber is also beneficial to the high thermal conductivity.
• Select
  Electrical characteristics and microstructures of
  Pr₆O₁₁-doped Bi₄Ti₃O₁₂ thin films

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 138-142.

  摘要 ( )   可视化   收藏

  Pr₆O₁₁-doped bismuth titanate (Bi_xPr_yTi₃O₁₂, BPT) thin films with random orientation were fabricated on Pt/Ti/SiO₂/Si substrates by rf magnetron sputtering technique, and the structures and ferroelectric properties of the films were investigated. XRD studies indicate that all of BPT films consist of single phase of a bismuth-layered structure with well-developed rod-like grains. For samples with y=0.06 , 0.3, 1.2 and 1.5, I—E characteristics exhibit negative differential resistance behaviors and their ferroelectric hysteresis loops are characterized by large leakage current. Whereas for samples with y=0.6 and 0.9, I—E characteristics are of  simple ohmic behaviors and their ferroelectric hysteresis loops are saturated and undistorted. The remanent polarization (P_r) and coercive field (E_c) of the BPT Film with y=0.9 are above 35 μC/cm² and 80 kV/cm, respectively.
• Select
  Microstructure and corrosion resistance of Fe-Al intermetallic coating on 45 steel synthesized by double glow plasma surface alloying technology

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 143-148.

  摘要 ( )   可视化   收藏

  A binary Fe-Al alloyed layer was synthesized on 45 steel by means of double glow plasma surface alloying technique. The corrosion-resisting layer prepared is composed of a sedimentary layer and a diffusion layer, with a total thickness of about 180 μm. The aluminum content of the alloyed layer shows gradual change from surface to the inside of substrate. The ideal profile is beneficial to the metallurgical bonding of the surface alloying layer with substrate materials. The microstructure of both layers consists of the Fe-Al intermetallic compound, which is FeAl with B2 structure in the sedimentary layer and Fe₃Al with incompletely ordered DO₃ structure in the diffusion layer. The protective film exhibits high micro-hardness. In comparison with the substrate of 45 steel, the corrosion resistance of the aluminized sample is much higher in 2.0% Na₂S and 0.05 mol/L Na₂SO₄ + 0.5 mol/L NaCl mixed solutions.
• Select
  Effect of Cu addition on corrosion resistance and shape memory effect of Fe-14Mn-5Si-9Cr-5Ni alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 149-153.

  摘要 ( )   可视化   收藏

  The modification of Fe-14Mn-5Si-9Cr-5Ni shape memory alloys(SMAs) by copper addition was carried out, aiming at further enhancing its corrosion resistance. The results of electrochemical potentiodynamic measurement and immersion test show that copper can remarkably improve the corrosion resistance in Cl⁻ solution. Otherwise, it is found that copper cannot markedly affect the mechanical properties nor the shape memory effect(SME). As for the effects of copper on Fe-Mn-Si based alloys, the austenite strengthening is one of the key factors to improve SME.
• Select
  Influence of Mg₂₁Ga₅Hg₃ compound on electrochemical properties of Mg-5%Hg-5%Ga alloy

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 154-159.

  摘要 ( )   可视化   收藏

  The Mg-Hg-Ga alloys are widely used in high power the seawater batteries. Mg-5%Hg-5%Ga alloy was melted and heat treatments at 573−773 K were performed for different times. The electrochemical and corrosion behaviors of the Mg-5%Hg-5%Ga alloy were studied by means of potentiodynamic, galvanostatic and electrochemical impedance spectroscopy(EIS). Scanning electron microscopy(SEM), energy dispersive spectrometry(EDS) and X-ray diffractometry(XRD) were employed to characterize the microstructures of the alloy. The results demonstrate that the best electrochemical activity occurs in the Mg-5%Hg-5%Ga alloy with homogeneously dispersed Mg₂₁Ga₅Hg₃ compound in α-Mg matrix. The most negative mean potential at 100 mA/cm² polarization current density can reach −1.928 V. The largest corrosion current density 19.37 mA/cm² of the Mg-5%Hg-5%Ga alloy appears in the Mg-5%Hg-5%Ga alloy with intergranular eutectic α-Mg and Mg₂₁Ga₅Hg₃.
• Select
  Effects of electrolyte components on properties of Al alloy anode

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 160-165.

  摘要 ( )   可视化   收藏

  The effects of Na₂SnO₃, In(OH)₃ and Na₂SnO₃+In(OH)₃ on the properties of Al alloy anode were studied in alkaline medium at 25 ℃. The self-corrosion rate of Al alloy anode was studied by method of H₂ immersed in aqueous medium, and the electrochemical properties of Al alloy anode were tested via galvanostatic discharge and dynamic potential methods. The results show that the self-corrosion rate of Al alloy anode in 4 mol/L NaOH+3 mol/L NaAlO₂ medium can be minimized by adding Na₂SnO₃, In(OH)₃ and Na₂SnO₃+ In(OH)₃. Na₂SnO₃, In(OH)₃ and Na₂SnO₃+In(OH)₃ make Al anodic potential shift positively in galvanostatic discharging. The most effective additive of Al alloy anode in 4 mol/L NaOH+3 mol/L NaAlO₂ medium is 0.075 mol/L Na₂SnO₃+0.005 mol/L In(OH)₃, integrating self-corrosion rate and electrochemical properties.
• Select
  Preparation and characteristics of Li₂FeSiO₄/C composite for cathode of
  lithium ion batteries

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 166-169.

  摘要 ( )   可视化   收藏

  A Li₂FeSiO₄/C composite cathode for lithium ion batteries was synthesized at 650 ℃ by solid-state reaction. The effects of carbon sources and carbon content on the properties of the Li₂FeSiO₄/C composites were investigated. The crystalline structure, morphology, carbon content and charge/discharge performance of Li₂FeSiO₄/C composites were determined by X-ray diffraction(XRD), scanning electron microscopy(SEM), carbon/sulfur analyzer and electrochemical measurements. As carbon content increases in the range of 5%−20%, the amount of Fe₃O₄ impurity phase decreases. The SEM micrographs show that the addition of the carbon is favorable for reducing the Li₂FeSiO₄ grain size. Using sucrose as carbon source, the Li₂FeSiO₄/C composite with 14.5% carbon synthesized at 650 ℃ shows good electrochemical performance with an initial discharge capacity of 144.8 mA∙h/g and a capacity retention ratio of 94.27% after 13 cycles.
• Select
  Synthesis and behavior of Al-stabilized α-Ni(OH)₂

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 170-175.

  摘要 ( )   可视化   收藏

  Nano-fibrous Al-stabilized α-Ni(OH)₂ was synthesized by the urea thermal decomposition method. The grain morphology, crystal structure, thermal stability, chemical composition and electrochemical performance of the Al-stabilized α-Ni(OH)₂ were investigated. It is found that the urea thermal decomposition is an appropriate way to precipitate the Al-stabilized α-Ni(OH)₂ with excellent performance. The fiber cluster TEM pattern shows that the synthesized α-Ni(OH)₂ powder is composed of agglomerates of much smaller primary particles. The stabilized α-Ni(OH)₂ powder with a 7.67 Å c-axis distance and low thermal stabilities is obtained. The FTIR spectrum shows that the materials contain absorbed water molecules, and intercalated CO₃²⁻ and SO₄²⁻ anions. The experimental α-Ni(OH)₂ electrode exhibits excellent electrochemical redox reversibility, high special capacity, good rate discharging performance and perfect cyclic stability. Moreover, the synthesized α-Ni(OH)₂ electrode also shows high discharge capacity and cyclic stability at high temperature. The electrode specific capacity remains 290 mA∙h/g at 60 ℃, which is only 15 mA∙h/g lower than its ambient value, and the capacity loss is 0.9 mA∙h/g per charge-discharge cycle.
• Select
  Synthesis and electrochemical performance of5V spinel LiNi_0.5Mn_1.5O₄ prepared by solid-state reaction

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 176-181.

  摘要 ( )   可视化   收藏

  Spinel compound LiNi_0.5Mn_1.5O₄ with high capacity and high rate capability was synthesized by solid-state reaction. At first, MnCl₂·4H₂O and NiCl₂·6H₂O were reacted with (NH₄)₂C₂O₄·H₂O to produce a precursor via a low-temperature solid-state route, then the precursor was reacted with Li₂CO₃ to synthesize LiNi_0.5Mn_1.5O₄. The effects of calcination temperature and time on the physical properties and electrochemical performance of the products were investigated. Samples were characterized by thermal gravimetric analysis(TGA), scanning electron microscopy(SEM), X-ray diffractometry(XRD), charge-discharge tests and cyclic voltammetry measurements. Scanning electron microscopy(SEM) image shows that as calcination temperature and time increase, the crystallinity of the samples is improved, and their grain sizes are obviously increased. It is found that LiNi_0.5Mn_1.5O₄ calcined at 800 ℃ for 6 h exhibits a typical cubic spinel structure with a space group of Fd3m. Electrochemical tests demonstrate that the sample obtained possesses high capacity and excellent rate capability. When being discharged at a rate as high as 5C after 30 cycles, the as-prepared LiNi_0.5Mn_1.5O₄ powders can still deliver a capacity of 101 mA∙h/g, which shows to be a potential cathode material for high power batteries.
• Select
  Effects of Na-substitution on structural and electronic properties of Li₂CoSiO₄ cathode material

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 182-186.

  摘要 ( )   可视化   收藏

  Na-substituted dilithium orthosilicate Li₂CoSiO₄ was investigated by performing density functional theory calculations within the GGA+U framework. The effects of Na-substitution on the electronic structures and structural properties of Li₂CoSiO₄ were presented. The results show that the Na-substitution on Li sites in Li₂CoSiO₄ induces a lowering of the conduction bands and a narrowing of the band gap, which could be helpful for enhancing the electronic conductivity. On the other hand, the Na-substitution on the Li ions in Li₂CoSiO₄ leads to the expansion of interlayer space of the adjacent corrugated layers. This lattice expansion effect would benefit the Li ion diffusion.
• Select
  Thermal property and microstructure of Al nanopowders produced by two evaporation routes

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 187-191.

  摘要 ( )   可视化   收藏

  Al nanopowders with diameters ranging from 20 to 50 nm passivated by Al₂O₃ coatings were produced by two different evaporation routes: induction heating evaporation (IHE) and laser-induction complex heating evaporation (LCHE). Thermal property of the nanopowders was investigated by differential thermal analysis (DTA) in dry oxygen environment. The results show that Al nanopowders produced by LCHE have the oxidation enthalpy change (∆H) of 3.54 kJ/g, while the ΔH of Al produced by IHE is 1.18 kJ/g. The phase constitution and microstructures of these nanopowders were revealed using X-ray diffraction (XRD) analysis, transmission electronic microscopy (TEM) and high-resolution transmission electronic microscopy (HRTEM). The results show that the two powders have the same composition and mean particle size, as well as the thickness of Al₂O₃ coatings (3−5 nm). Defects were observed on the surfaces of the particles by LCHE. However, the defects were not detected by HRTEM on the surfaces of the particles by IHE. The results prove that there exists excessive stored energy in Al nanopowders by LCHE because of the nonequilibrium condition brought by laser and the defects are the storage area of the excessive stored energy. Propellants composed of Al nanopowders by LCHE show higher energy level and specific impulse.
• Select
  Preparation of TiO₂ nanotube on glass by anodization of Ti films at room temperature

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 192-198.

  摘要 ( )   可视化   收藏

  In order to fabricate titania nanotubes on glass substrate, Ti thin films (700−900 nm) were first deposited by radio-frequency(RF) magnetron sputtering and then anodized in an aqueous HF electrolyte solution at room temperature. The morphology and structure of the nanotubes were identified by means of field emission scanning electron microscopy(FE-SEM) and X-ray diffractometry(XRD). The effects of anodization parameters (concentration of electrolyte, applied voltage) on nanotube morphology were comprehensively investigated. The results show that the dense and crystalline Ti film can be obtained on the unheated glass substrate under the sputtering power of 150 W, and the anodization current and voltage play significant roles in the formation of titania nanotube with different tube sizes.
Computational Materials Science
• Select
  Thermodynamic investigation of Fe-Ti-Y ternary system

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 199-204.

  摘要 ( )   可视化   收藏

  An extensive investigation on the Fe-Ti-Y system was performed via experimental measurement and thermodynamic calculation. The Fe-Ti-Y ternary couples at 1 273 K were prepared with a desire to provide accurate phase relationships needed for the refinement of this ternary phase diagram. And a tentative isothermal section of Fe-Ti-Y at 1 273 K was built based on the experimental information. In the thermodynamic modeling, the thermodynamic parameters for the Ti-Y binary system and the ternary phase in the Fe-Ti-Y system were evaluated. Those for the Fe-Ti and Fe-Y systems from literature were slightly modified for the compatibility. The isothermal sections of Fe-Ti-Y ternary system at 873 K and 1 273 K were calculated. The ternary compound Fe₁₁TiY and Fe₂(Ti, Y) solid solution formed from Fe₂Ti and Fe₂Y are detected, which is in good agreement with the literature information.
• Select
  First-principles investigation of Mg₂CoH₅ complex hydride

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 205-209.

  摘要 ( )   可视化   收藏

  Within the framework of density functional theory, crystal structure parameters, physical properties, electronic structures and thermal stability of Mg₂CoH₅ complex hydride are comprehensively investigated. The optimized structural parameters including lattice constants, atomic positions and bond lengths are well close to the experimental data determined from X-ray and neutron powder diffraction. A detailed study on the energy band, density of states (DOS) and charge density distribution shows the orbital hybridization and bonding characteristics of the complex hydride. It is found that Mg₂CoH₅ is a semiconductor with a pseudo-gap of about 1.638 1 eV, and there is a mixed ionic-covalent bonding between Co and H in CoH₅ complexes embedded in the matrix Mg²⁺ cations. The calculated formation enthalpy of Mg₂CoH₅ is in good agreement with the experimentally determined value.
• Select
  Atomic simulations for surface-initiated melting of Nb(111)

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 210-214.

  摘要 ( )   可视化   收藏

  A modified analytic embedded-atom model(MAEAM) was applied to investigate surface premelting and melting behaviors of Nb(111) plane by molecular dynamics(MD) simulations. First the relaxation of surface interface space at 300 K was studied. Then a number N of the disordered atoms per unit area was determined at the given temperatures to investigate the surface premelting and melting evolution. The obtained results indicated that the premelting phenomena occurred at about 1 100 K and a liquid-like layer emerged on (111) plane simultaneously. As temperature increased up to 2 200 K, the number N grew logarithmically for short-range metallic interactions. Upon 2 350 K surface melting generated originally and the number N increased exponentially with the incremental temperature.
• Select
  Multi-pass spinning of thin-walled tubular part with longitudinal inner ribs

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 215-221.

  摘要 ( )   可视化   收藏

  Based on the process experiments, micrography analysis was dedicated to advancing the understanding of plastic flow of the metal in backward ball spinning of thin-walled tubular part with longitudinal inner ribs. Micrography analysis reveals that severe plastic deformation leads to grain refinement, grain orientation and grain flow line of the spun part. Based on rigid-plastic finite element method, DEFORME3D finite element code was used to simulate and analyze multi-pass backward ball spinning of thin-walled tubular part with longitudinal inner ribs. Finite element simulation results involve the distributions of the strain, the shape variation of the inner ribs as well as the prediction of the spinning loading.
Mine Engineering, Metallurgical Engineering and Ch
• Select
  Isolation and identification of moderately thermophilic acidophilic iron-oxidizing bacterium and its bioleaching characterization

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 222-227.

  摘要 ( )   可视化   收藏

  A moderately thermophilic acidophilic iron-oxidizing bacterium ZW-1 was isolated from Dexing mine, Jiangxi Province, China. The morphological, biochemical and physiological characteristics, 16S rRNA sequence and bioleaching characterization of strain ZW-1 were studied. The optimum growth temperature is 48 ℃, and the optimum initial pH is 1.9. The strain can grow autotrophically by using ferrous iron or elemental sulfur as sole energy sources. The strain is also able to grow heterotrophically by using peptone and yeast extract powder, but not glucose. The cell density of strain ZW-1 can reach up to 1.02×10⁸ /mL with addition of 0.4 g/L peptone. A phylogenetic tree was constructed by comparing with the published 16S rRNA sequences of the relative bacteria species. In the phylogenetic tree, strain ZW-1 is closely relative to Sulfobacilus acidophilus with more than 99% sequence similarity. The results of bioleaching experiments indicate that the strain could oxidize Fe²⁺ efficiently, and the maximum oxidizing rate is 0.295 g/(L·h). It could tolerate high concentration of Fe³⁺ and Cu²⁺ (35 g/L and 25 g/L, respectively). After 20 d, 44.6% of copper is extracted from chalcopyrite by using strain ZW-1 as inocula.
• Select
  Flotation of aluminosilicate minerals using alkylguanidine collectors

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 228-234.

  摘要 ( )   可视化   收藏

  The flotation mechanism of aluminosilicate minerals using alkylguanidine collectors was studied through flotation experiments, Zeta potential measurements and FT-IR spectrum analysis. It is shown that kaolinite, illite and pyrophyllite all exhibit good floatability with alkylguanidines as collectors at pH 4−12. The flotation recoveries rise with the increase of the carbon chain length. Isoelectric point(IEP) is determined to be 3.5, 3.0 and 2.3 for kaolinite, illite and pyrophyllite, respectively. However, it is anomalous that the presence of cationic collectors has less influence on the negatively charged mineral surfaces. It is explained by the special structure of guanidine which is one of the strongest bases, having two —NH₂ groups. One of them maybe interacts with minerals by electrostatic forces, and the other maybe forms hydrogen bonding with OH⁻ ions on the aluminosilicate surfaces or in the aqueous solution, increasing the density of negative charge on the aluminosilicate surface and leading unpronounced positive charge to increase on the aluminosilicate. By combining the flotation tests, Zeta potential and FTIR measurements above, the interaction mechanism can be concluded. The simultaneous presence of cationic and neutral amine groups makes it possible for SAG cation to bind on three aluminosilicate minerals by both electrostatic attraction and hydrogen bonding. While in acidic medium, the interaction of the alkylguanidines on the aluminosilicate surfaces is mainly by means of electrostatic force and hydrogen bond; in the alkaline medium, it is by the way of electrostatic effect and hydrogen bond.
• Select
  Determination of trace mercury in compost extract by inhibition based glucose oxidase biosensor

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 235-240.

  摘要 ( )   可视化   收藏

  A novel inhibition based biosensor of glucose oxidase(GOx) for environmental mercury detection was developed. An electropolymerized aniline membrane was prepared on a platinum electrode containing ferrocene as electron transfer mediator, on which GOx was cross-linked by glutaraldehyde. The response of the sensor was based on the current reduction in the electrochemical system by inhibition of mercury against GOx electrode. The detection limit of the inhibition-based sensor for mercury is 0.49 μg/L, and the linear response ranges are 0.49−783.21 μg/L and 783.21 μg/L−25.55 mg/L. The GOx membrane can be completely reactivated after inhibition, and remains 70% of the activity in more than one month. The sensor was used for mercury determination in compost extract with good results.
• Select
  Chromium accumulation, microorganism population and
  enzyme activities in soils around chromium-containing slag heap of
  steel alloy factory

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 241-248.

  摘要 ( )   可视化   收藏

  The environmental risk of chromium pollution is pronounced in soils adjacent to chromate industry. It is important to investigate the functioning of soil microorganisms in ecosystems exposed to long-term contamination by chromium. 45 soil samples obtained from different places of the slag heap in a steel alloy factory were analyzed for chromium contamination level and its effect on soil microorganisms and enzyme activities. The results show that the average concentrations of total Cr in the soil under the slag heap, adjacent to the slag heap and outside the factory exceed the threshold of Secondary Environmental Quality Standard for Soil in China by 354%, 540% and 184%, respectively, and are 15, 21 and 9 times higher than the local background value, respectively. Elevated chromium loadings result in changes in the activity of the soil microbe, as indicated by the negative correlations between soil microbial population and chromium contents. Dehydrogenase activity is greatly depressed by chromium in the soil. The results imply that dehydrogenase activity can be used as an indicator for the chromium pollution level in the area of the steel alloy factory.
• Select
  Thermodynamic equilibrium of CaSO₄-Ca(OH)₂-H₂O system

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 249-252.

  摘要 ( )   可视化   收藏

  The pc—pH diagrams of the CaSO₄-Ca(OH)₂-H₂O system and its two subsystems at 298.15 K were constructed according to the theory of thermodynamic equilibrium. The interaction characteristics between the solubility of CaSO₄(s) and Ca(OH)₂(s) can be found out from the diagrams. CaSO₄(s), Ca(OH)₂(s) and solution coexist when the pH value of solution is about 13.2. CaSO₄(s) with the minimum solubility of 0.411 g/L is in equilibrium with solution when the pH value is lower than 13.2, and Ca(OH)₂(s) with the minimum solubility of 2.749 g/L is in equilibrium with solution at the pH value over 13.2, which provides a theoretical basis for the treatment and reuse of industrial wastewater, especially for the wastewater containing sulfate which can be treated by lime-milk neutralization.
• Select
  Removal of copper from nickel anode electrolyte through ion exchange

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 253-258.

  摘要 ( )   可视化   收藏

  An novel method for removal of copper from nickel anodic electrolyte through ion exchange was studied after cupric deoxidization. Orthogonal design experiments show the optimum conditions of deoxidizing cupric into Cu⁺ in the nickel electrolyte are the reductive agent dosage is 4.5 times as the theoretic dosage and reaction time is 0.5 h at 40 ℃ and pH 2.0. Ion exchange experiments show that the breakthrough capacity(Y) decreases with the increase of the linear flow rate(X): Y=1.559−0.194X+   0.006 7X². Breakthrough capacity increases with the increase of the ratio of height to radius(RRH). The higher the initial copper concentration, the less the breakthrough capacity(BC). SO₄²⁻ and nickel concentration have no obvious change during the process of sorption, so it is not necessary to worry about the loss of nickel during the sorption process. Desorption experiments show that copper desorption from the resin is made perfectly with NaCl solution added with 4% (volume fraction) H₂O₂ (30%) and more than 100 g/L CuCl₂ solution is achieved.
• Select
  Numerical simulation of high temperature air combustion in
  aluminum hydroxide gas suspension calcinations

  匿名

  中国有色金属学报（英文版）. 2009, 19(01): 259-266.

  摘要 ( )   可视化   收藏

  The high temperature air combustion(HiTAC) process in gas suspension calcinations(GSC) was studied by using a CFD software FLUENT that can simulate the three-dimensional physical model of GSC with the k-epsilon turbulent viscous model, PDF non-premixed combustion species model, P1 radiation model, thermal and prompt NO pollution model. The simulation vividly describes the distributions of the temperature, velocity and consistency fields. Finally, the optimal operation conditions and igniter configuration of particular fuel combustion are obtained by analyzing and comparing the simulation results. And the emission quantity of NO_x, CO and CO₂ deduced from computation can play a role as reference. These optimal and estimated values are beneficial to practical operation.