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Dual-functions of the carbon-confined oxygen on the capacitance and cycle stability enhancements of Zn-ion capacitors Yi Zhang, Zhimin Zou, Qi Liu, Yu Qiao, Chunhai Jiang J. Mater. Sci. Technol.    2025, 221 (0): 278-288.   DOI: 10.1016/j.jmst.2024.10.003 Abstract （11473）      PDF       Knowledge map    Save Zinc-ion capacitors (ZICs) are promising energy storage devices due to their balance between the energy and power densities inherited from Zn-ion batteries and supercapacitors, respectively. However, the low specific capacitance of carbon cathode materials and the dendrite growth on Zn anode have set fatal drawbacks to their energy density and cycle stability. Herein, we demonstrate that, in 1 M Zn(CF3SO3)2/DMF (N, N-dimethylformamide) electrolyte, confining oxygen in carbon cathode materials via high-energy ball milling can synergistically introduce additional pseudocapacitance on the cathode side while suppressing the dendrite growth on Zn anode side, which jointly lead to high energy density (94 Wh kg-1 at 448 W kg-1) and long cycle stability of ZICs. The hydroxyl group in carbon cathode can be transformed to C-O-Zn together with the release of protons during the initial discharge, which in turn stimulates the defluorination of CF3SO3- anions and formation of ZnF2 on both cathode and anode. The ZnF2 formed on the surface of the Zn anode suppresses the dendrite growth by regulating the Zn2+ deposition/stripping in a reticular structure, resulting in the excellent cycle stability. This work provides a facile strategy to rationally design and construct high energy and stable ZICs through engineering the oxygen-bearing functional groups in carbon cathode materials. Reference | Related Articles | Metrics | Comments（0）

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Controlled Growth of One-Dimensional Oxide Nanomaterials Xiaosheng FANG, Lide ZHANG J Mater Sci Technol    2006, 22 (01): 1-18.   Abstract （6011）   HTML （4）    PDF（pc） （10236KB）（6555）       Knowledge map    Save This article reviews the recent developments in the controlled growth of one-dimensional (1D) oxide nanomaterials, including ZnO, SnO2, In2O3, Ga2O3, SiOx, MgO, and Al2O3. The growth of 1D oxide nanomaterials was carried out in a simple chemical vapor transport and condensation system. This article will begin with a survey of nanotechnology and 1D nanomaterials achieved by many researchers, and then mainly discuss on the controlled growth of 1D oxide nanomaterials with their morphologies, sizes, compositions, and microstructures controlled by altering experimental parameters, such as the temperature at the source material and the substrate, temperature gradient in the tube furnace, the total reaction time, the heating rate of the furnace, the gas flow rate, and the starting material. Their roles in the formation of various morphologies are analyzed and discussed. Finally, this review will be concluded with personal perspectives on the future research directions of this area. Reference | Related Articles | Metrics | Comments（0）

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Preparation of α-Fe2O3 Nanodisks by Blocking the Growth of (001) Plane Baoliang Lv,Yao Xu,Dong Wu,Yuhan Sun J Mater Sci Technol    2009, 25 (02): 155-158.   Abstract （5594）   HTML （2）    PDF（pc） （1364KB）（1720）       Knowledge map    Save Based on the difference of hydroxy group configuration on different planes of α-Fe2O3 nanoparticles, using the special adsorption and coordination of phosphate on the (001) plane of α-Fe2O3 , well-crystallized and well dispersed α-Fe2O3 nanodisks with diameter of 150-200 nm and thickness of 40-80 nm were synthesized via a hydrothermal method. The magnetic properties of synthesized nanodisks were investigated. It was found that the nanodisks possessed a saturation magnetization (Ms) of 0.38 emu/g, a remanent magnetization (Mr) of 0.031 emu/g and a coercivity of 452.91 Oe at room temperature. The Mr and coercivity of synthesized α-Fe2O3  nanodisks are higher and the Ms is lower than those of other previously reported α-Fe2O3 nanostructures. Reference | Related Articles | Metrics | Comments（0）

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Microstructure and Properties of Low Temperature Composite Chromized Layer on H13 Tool Steel Cuilan WU, Chengping LUO, Ganfeng ZOU J Mater Sci Technol    2005, 21 (02): 251-255.   Abstract （5035）   HTML （0）    PDF（pc） （559KB）（1480）       Knowledge map    Save Low temperature composite chromizing is a process composed of a plain ion-carbonitriding or ion-nitriding at 550~580℃, followed by a low-temperature chromizing in a salt-bath of 590℃. The microstructure and properties of the low temperature composite chromized layer on H13 tool steel were investigated using metallography, X-ray diffraction, microanalysis, hardness and wear tests. It was found that this low temperature process was thermodynamically and kinetically possible, and the composite chromized layer on H13 steel, with a thickness of 3~6 μm, consisted of three sub-layers (bands), viz. the outer Cr-rich one, the intermediate (black) one, and the inner, original white layer. After chromizing, the former diffusion layer was thickened. The results of X-ray diffraction showed that the composite chromized layer contained such nitrides and carbides of chromium as CrN, Cr2N, (Cr, Fe)23C6, and (Cr, Fe)7C3, as well as plain α-(Fe, Cr). A high surface microhardness of 1450~1550 HV0.025, which is much higher than that obtained by the conventional ion carbonitriding and ion nitriding, was obtained. In addition, an excellent wear resistance was gained on the composite chromized layer. Reference | Related Articles | Metrics | Comments（0）

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One-dimensional (1D) ZnS Nanomaterials and Nanostructures Xiaosheng FANG, Lide ZHANG J. Mater. Sci. Technol.    2006, 22 (06): 721-736.   Abstract （4675）   HTML （6）    PDF（pc） （3313KB）（4551）       Knowledge map    Save One-dimensional (1D) nanomaterials and nanostructures have received much attention due to their potential interest for understanding fundamental physical concepts and for applications in constructing nanoscale electric and optoelectronic devices. Zinc sulfide (ZnS) is an important semiconductor compound of II-VI group, and the synthesis of 1D ZnS nanomaterials and nanostructures has been of growing interest owing to their promising application in nanoscale optoelectronic devices. This paper reviews the recent progress on 1D ZnS nanomaterials and nanostructures, including nanowires, nanowire arrays, nanorods, nanobelts or nanoribbons, nanocables, and hierarchical nanostructures etc. This article begins with a survey of various methods that have been developed for generating 1D nanomaterials and nanostructures, and then mainly focuses on structures, synthesis, characterization, formation mechanisms and optical property tuning, and luminescence mechanisms of 1D ZnS nanomaterials and nanostructures. Finally, this review concludes with personal views towards future research on 1D ZnS nanomaterials and nanostructures. Reference | Related Articles | Metrics | Comments（0）

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Antibacterial Characterization of Silver Nanoparticles against E. Coli ATCC-15224 M.Raffi, F.Hussain, T.M.Bhatti, J.I.Akhter, A.Hameed, M.M.Hasan J Mater Sci Technol    2008, 24 (02): 192-196.   Abstract （4578）   HTML （30）    PDF（pc） （533KB）（8523）       Knowledge map    Save Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation (IGC) method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli (E.coli) was carried out in liquid as well as solid growth media. Scanning electron microscopy (SEM) and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity. Reference | Related Articles | Metrics | Comments（0）

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Doped-TiO2 Photocatalysts and Synthesis Methods to Prepare TiO2 Films Ying CUI, Hao DU, Lishi WEN J Mater Sci Technol    2008, 24 (05): 675-689.   Abstract （4340）   HTML （13）    PDF（pc） （6912KB）（3869）       Knowledge map    Save TiO2 is a promising photocatalyst. However, the low photocatalytic efficiency calls for the modification of TiO2. Metal- and nonmetal-doping of TiO2 have been proved to be effective ways to enhance photocatalytic properties. This review provides a deep insight into the understanding of the metal- and nonmetal-doped TiO2 photocatalysts. This article begins with the introduction of the crystal structures of TiO2 and applications of TiO2 materials. We then reviewed the doped-TiO2 system in two categories: (1) metal-doped TiO2 photocatalysts system, and (2) nonmetal-doped TiO2 photocatalysts system. Both experimental results and theoretical analyses are elaborated in this section. In the following part, for the advantages of TiO2 thin films over particles, various preparation methods to obtain TiO2 thin films are briefly discussed. Finally, this review ends with a concise conclusion and outlook of new trends in the development of TiO2-based photocatalysts. Reference | Related Articles | Metrics | Comments（0）

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One-Dimensional (1-D) Nanoscale Heterostructures Guozhen SHEN, Di CHEN, Yoshio B, O, Dmitri GOLBERG J Mater Sci Technol    2008, 24 (04): 541-549.   Abstract （3801）   HTML （2）    PDF（pc） （2203KB）（2343）       Knowledge map    Save One-dimensional (1-D) nanostructures have been attracted much attention as a result of their exceptional properties, which are different from bulk materials. Among 1-D nanostructures, 1-D heterostructures with modulated compositions and interfaces have recently become of particular interest with respect to potential applications in nanoscale building blocks of future optoelectronic devices and systems. Many kinds of methods have been developed for the synthesis of 1-D nanoscale heterostructures. This article reviews the most recent development, with an emphasize on our own recent efforts, on 1-D nanoscale heterostructures, especially those synthesized from the vapor deposition methods, in which all the reactive precursors are mixed together in the reaction chamber. Three types of 1-D nanoscale heterostructures, defined from their morphologies characteristics, are discussed in detail, which include 1-D co-axial core-shell heterostructures, 1-D segmented heterostructures and hierarchical heterostructures. This article begins with a brief survey of various methods that have been developed for synthesizing 1-D nanoscale heterostructures and then mainly focuses on the synthesis, structures and properties of the above three types of nanoscale heterostructures. Finally, this review concludes with personal views towards the topic of 1-D nanoscale heterostructures. Reference | Related Articles | Metrics | Comments（0）

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Effects of deformation processes on morphology, microstructure and corrosion resistance of LDHs films on magnesium alloy AZ31 Jing Chen, Liang Wu, Xingxing Ding, Qiang Liu, Xu Dai, Jiangfeng Song, Bin Jiang, Andrej Atrens, Fusheng Pan J. Mater. Sci. Technol.    2021, 64 (0): 10-20.   DOI: 10.1016/j.jmst.2019.10.007 Abstract （3151）   HTML （1109）    PDF（pc） （6026KB）（2590）       Knowledge map    Save Highly oriented Mg-Al layered double hydroxide (LDHs) films were deposited on magnesium alloy AZ31 with different deformation processes by an easy in-situ growth method. The characteristics of the films were investigated by optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical, immersion and hydrogen evolution tests. The corrosion protection performance ranked the LDHs films as the increasing series: CS-LDHs (as-cast sample with LDHs) < AE-LDHs (asymmetric extrusion sample with LDHs) < SE-LDHs (symmetric extrusion sample with LDHs) < RS-LDHs (rolled sample with LDHs). A thicker and more compact LDH conversion coating was formed on the RS sample, and had the best corrosion protection performance. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Effect of Notch Location on Fatigue Life Prediction of Strength Mismatched HSLA Steel Weldments S.Ravi, V.Balasubramanian, S.Nemat Nasser J Mater Sci Technol    2004, 20 (02): 129-135.   Abstract （3127）   HTML （1）    PDF（pc） （3743KB）（3270）       Knowledge map    Save Welding of high strength low alloy steels (HSLA) involves usage of low, even and high strength filler materials (electrodes) than the parent material depending on the application of the welded structures and the availability of the ˉller material. In the present investigation, the fatigue crack growth behaviour of weld metal (WM) and heat affected zone (HAZ) regions of under matched (UM), equal matched (EM) and over matched (OM) joints has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. Shielded metal arc welding (SMAW) process has been used to fabricate the butt joints. Centre cracked tension (CCT) specimen has been used to evaluate the fatigue crack growth behaviour of the welded joints. Fatigue crack growth experiments have been conducted using servo hydraulic controlled fatigue testing machine at constant amplitude loading (R=0). A method has been proposed to predict the fatigue life of HSLA steel welds using fracture mechanics approach by incorporating influences of mismatch ratio (MMR) and notch location. Reference | Related Articles | Metrics | Comments（0）

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Surface Nanocrystallization (SNC) of Metallic Materials-Presentation of the Concept behind a New Approach Ke LU, Jian LU J Mater Sci Technol    1999, 15 (03): 193-197.   Abstract （3109）   HTML （93）    PDF（pc） （1527KB）（4438）       Knowledge map    Save In this paper, a concept of surface nanocrystallization (SNC) of metallic materials is introduced. Three types of SNC processes are classified. Different SNC mechanisms and possible techniques for SNC are discussed with emphasis on mechanically induced surface self-nanocrystallization. Further development and prospects are addressed with respect to the properties and behaviors of the materials with a nanocrystalline surface. Enhancement of the behavior of the engineering materials by means of the SNC technology and its industrial application possibilities are analyzed. Reference | Related Articles | Metrics | Comments（0）

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Current Status in Layered Ternary Carbide Ti3SiC2, a Review H.B. Zhang,Y.W. Bao,Y.C. Zhou J Mater Sci Technol    2009, 25 (01): 1-38.   Abstract （3065）   HTML （12）    PDF（pc） （7876KB）（2458）       Knowledge map    Save This article provides a review of current research activities that concentrate on Ti3SiC2. We begin with an overview of the crystal and electronic structures, which are the basis to understand this material. Followings are the synthetic strategies that have been exploited to achieve, and the formation mechanism of Ti3SiC2. Then we devote much attentions to the mechanical properties and oxidation/hot corrosion behaviors of Ti3SiC2 as well as some advances achieved recently. At the end of this paper, we elaborate on some new discoveries in the Ti3SiC2 system, and also give a brief discussion focused on the "microstructure -property" relationship. Reference | Related Articles | Metrics | Comments（0）

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Metal Fabrication by Additive Manufacturing Using Laser and Electron Beam Melting Technologies Lawrence E. Murr, Sara M. Gaytan, Diana A. Ramirez, Edwin Martinez, Jennifer Hernandez, Krista N. Amato, Patrick W. Shindo, Francisco R. Medina, Ryan B. Wicker J Mater Sci Technol    2012, 28 (1): 1-14.   Abstract （3042）   HTML （23）          Knowledge map    Save Selective laser melting (SLM) and electron beam melting (EBM) are relatively new rapid, additive manufacturing technologies which can allow for the fabrication of complex, multi-functional metal or alloy monoliths by CAD-directed, selective melting of precursor powder beds. By altering the beam parameters and scan strategies, new and unusual, even non-equilibrium microstructures can be produced; including controlled microstructural architectures which ideally extend the contemporary materials science and engineering paradigm relating structure-properties-processing-performance. In this study, comparative examples for SLM and EBM fabricated components from pre-alloyed, atomized precursor powders are presented. These include Cu, Ti-6Al-4V, alloy 625 (a Ni-base superalloy), a Co-base superalloy, and 17-4 PH stainless steel. These systems are characterized by optical metallography, scanning and transmission electron microscopy, and X-ray diffraction. Reference | Related Articles | Metrics | Comments（0）

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Morphology Change of Metastable Regrown Graphite with Boron Additive under HPHT Chuanyi Zang,Xiaozhou Chen,Qiang Hu,Wei Guo,Guofeng Huang J Mater Sci Technol    2009, 25 (04): 539-542.   Abstract （2993）   HTML （3）    PDF（pc） （868KB）（1425）       Knowledge map    Save By temperature gradient method under high pressure and high temperature (HPHT), with NiMnCo alloy as the solvent metal, at diamond-stable region of about 5.4 GPa and 1500 K, metastable regrown graphite crystals of different morphology were synthesized. With B as an additive incorporated into the NiMnCo-C system, metastable regrown graphite crystals of sphere-like shape were firstly obtained under HPHT. If the growth system does not contain B, sheet-like regrown graphite crystals, most with regular hexagonal morphology, are grown upwards and standing vertically in the metal solvent. When B additive of 1.0 wt pct was added into carbon source (graphite powder), all metastable regrown graphite crystals took on the habit of regular sphere-like morphology, and were grown by a spiral layer growth mechanism. Reference | Related Articles | Metrics | Comments（0）

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Effect of Sintering Temperature on the Texturing Behavior of NaCo2O4-δ Synthesized by Urea Auto-Combustion Method Yue Zhang,Wei Wei,Yong Liu,Benpeng Zhu,Ping Huang,Ziyu Wang,Zhongpo Zhou,Wufeng Tang,Jing Shi J Mater Sci Technol    2009, 25 (06): 742-744.   Abstract （2941）   HTML （0）    PDF（pc） （437KB）（1335）       Knowledge map    Save Polycrystalline NaCo2O4-δ materials were prepared using the urea auto-combustion method. The reaction process and crystal growth were investigated through X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), and Fourier transform infrared spectrometry (FTIR). The results indicate that the formation temperature of NaCo2O4-δ is about 620°C, which is lower than that for solid-state reaction. XRD results show that the texturing along c-axis occurred as the powders calcined at 700°C were pressed into pellets with subsequently sintering, and the degree of such texturing increases  with increasing sintering temperature. Surface morphologies by scanning electron microscopy (SEM) also indicate that the texturing show dependence on sintering temperature. The grains on the surfaces of the pellets sintered at 750 and 850°C have some growth trend along a-b planes, while the grains on the surface of the pellet sintered at 950°C show an obvious growth trend toward c-axis. Reference | Related Articles | Metrics | Comments（0）

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Layered Machinable and Electrically Conductive Ti2AlC and Ti3AlC2 Ceramics: a Review X.H. Wang Y.C. Zhou J Mater Sci Technol    2010, 26 (5): 385-416.   Abstract （2918）   HTML （10）    PDF（pc） （2488KB）（2474）       Knowledge map    Save Ti2AlC and Ti3AlC2 are the most light-weight and oxidation resistant layered ternary carbides belonging to the MAX phases. This review highlights recent achievements on the processing, microstructure, physical, mechanical and chemical properties of these two machinable and electrically conductive carbides. Ti2AlC and Ti3AlC2 display superior properties such as fracture toughness, electrical and thermal conductivities, and oxidation resistance over their binary counterpart. This paper provides a comprehensive overview of the processing-microstructure-property correlations of these two carbides. Potential fields of applications for Ti2AlC and Ti3AlC2 are surveyed. In addition, we point out methods for further improving their properties in some specific applications through appropriate structural design and modification. Reference | Related Articles | Metrics | Comments（0）

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Optimization of the in vitro biodegradability, cytocompatibility, and wear resistance of the AZ31B alloy by micro-arc oxidation coatings doped with zinc phosphate Chao Yang, Suihan Cui, Ricky K.Y. Fu, Liyuan Sheng, Min Wen, Daokui Xu, Ying Zhao, Yufeng Zheng, Paul K. Chu, Zhongzhen Wu J. Mater. Sci. Technol.    2024, 179 (0): 224-239.   DOI: 10.1016/j.jmst.2023.09.019 Abstract （2887）      PDF       Knowledge map    Save As implanted bone fixation materials, magnesium (Mg) alloys have significant advantages because the density and elastic modulus are closest to those of the human bone and they can bio-degrade in the physiological environment. However, Mg alloys degrade too rapidly and uncontrollably thus hampering clinical adoption. In this study, a highly corrosion-resistant zinc-phosphate-doped micro-arc oxidation (MAO) coating is prepared on the AZ31B alloy, and the degradation process is assessed in vitro. With increasing zinc phosphate concentrations, both the corrosion potentials and charge transfer resistance of the AZ31B alloy coated with MAO coatings increase gradually, while the corrosion current densities diminish gradually. Immersion tests in the simulated body fluid (SBF) reveal that the increased zinc phosphate concentration in MAO coating decreases the degradation rate, consequently reducing the release rates of Mg2+ and OH- in the physiological micro-environment, which obtains the lowest weight loss of only 5.22% after immersion for 56 days. Effective regulation of degradation provides a weak alkaline environment that is suitable for long-term cell growth and subsequent promotion of bone proliferation, differentiation, mineralization, and cytocompatibility. In addition, the zinc-phosphate-doped MAO coatings show an improved wear resistance as manifested by a wear rate of only 3.81 × 10-5 mm3 N-1 m-1. The results reveal a suitable strategy to improve the properties of biodegradable Mg alloys to balance tissue healing with mechanical degradation. Reference | Related Articles | Metrics | Comments（0）

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Die Casting Mold Design of the Thin-walled Aluminum Case by Computational Solidification Simulation Young-Chan Kim, Chang-Seog Kang, Jae-Ik Cho, Chang-Yeol Jeong, Se-Weon Choi, Sung-Kil Hong J Mater Sci Technol    2008, 24 (03): 383-388.   Abstract （2840）   HTML （17）    PDF（pc） （3805KB）（6219）       Knowledge map    Save Recently, demand for the lightweight alloy in electric/electronic housings has been greatly increased. However, among the lightweight alloys, aluminum alloy thin-walled die casting is problematic because it is quite difficult to achieve sufficient fluidity and feedability to fill the thin cavity as the wall thickness becomes less than 1 mm. Therefore, in this study, thin-walled die casting of aluminum (Al-Si-Cu alloy: ALDC 12) in size of notebook computer housing and thickness of 0.8 mm was investigated by solidification simulation (MAGMA soft) and actual casting experiment (Buhler Evolution B 53D). Three different types of gating design, finger, tangential and split type with 6 vertical runners, were simulated and the results showed that sound thin-walled die casting was possible with tangential and split type gating design because those gates allowed aluminum melt to flow into the thin cavity uniformly and split type gating system was preferable gating design comparing to tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. Also, the solidification simulation agreed well with the actual die-casting and the casting showed no casting defects and distortion. Reference | Related Articles | Metrics | Comments（0）

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Investigation on Structure and Properties of Brass Casting M.M.Haque, A.A.Khan J Mater Sci Technol    2008, 24 (03): 299-301.   Abstract （2812）   HTML （15）    PDF（pc） （5589KB）（5721）       Knowledge map    Save In this work, alpha (α) brass was poured in green sand mould and metallic chill mould at about 1050℃. Sand casting method and metallic chill casting method are representing the slow and fast cooling rates of the castings, respectively. The slow cooling rate in the sand mould produces larger grains, while the metallic chill mould produces smaller grains in the castings. As the grain size decreases, the strength of the cast brass increases; micro-porosity in the casting decreases and the tendency for the casting to fracture during solidification decreases. Thus, the faster cooling rate casting offers higher strength, density and hardness compared to the slow cooling rate casting. Reference | Related Articles | Metrics | Comments（0）

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Effects of Alloying Elements on the Microstructures and Mechanical Properties of Heavy Section Ductile Cast Iron G.S.Cho, K.H.Choe, K.W.Lee, A.Ikenaga J Mater Sci Technol    2007, 23 (01): 97-101.   Abstract （2770）   HTML （18）    PDF（pc） （1032KB）（7840）       Knowledge map    Save The effects of alloying elements on the as-cast microstructures and mechanical properties of heavy section ductile cast iron were investigated to develop press die material having high strength and high ductility. Measurements of ultimate tensile strength, 0.2% proof strength, elongation and unnotched Charpy impact energy are presented as a function of alloy amounts within 0.25 to 0.75 wt pct range. Hardness is measured on the broken tensile specimens. The small additions of Mo, Cu, Ni and Cr changed the as-cast mechanical properties owing to the different as-cast matrix microstructures. The ferrite matrix of Mo and Ni alloyed cast iron exhibits low strength and hardness as well as high elongation and impact energy. The increase in Mo and Ni contents developed some fractions of pearlite structures near the austenite eutectic cell boundaries, which caused the elongation and impact energy to drop in a small range. Adding Cu and Cr elements rapidly changed the ferrite matrix into pearlite matrix, so strength and hardness were significantly increased. As more Mo and Cr were added, the size and fraction of primary carbides in the eutectic cell boundaries increased through the segregation of these elements into the intercellular boundaries. Related Articles | Metrics | Comments（0）

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Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film Yuan Zewei,ZhuJi Jin,Xingwei Ma,Boxian Dong J Mater Sci Technol    2009, 25 (03): 319-324.   Abstract （2758）   HTML （1）    PDF（pc） （900KB）（1770）       Knowledge map    Save Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost. By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere. However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality. In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS). The process of ball milling, composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed. The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix. The density of composite can be improved by mechanical alloying. The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability. These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film. Reference | Related Articles | Metrics | Comments（0）

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Laser-Heated Diamond-Anvil Cell (LHDAC) in Materials Science Research N.V.Ch, ra Shekar, P.Ch.Sahu, K.Govinda Rajan J Mater Sci Technol    2003, 19 (06): 518-525.   Abstract （2723）   HTML （4）    PDF（pc） （1568KB）（1278）       Knowledge map    Save Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored. Reference | Related Articles | Metrics | Comments（0）

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The Role of Nd Solid-Solution and Grain-Boundary Segregation in Binary NiAl Intermetallic Compound Weili REN, Jiangting GUO, Gusong LI, Jiyang ZHOU J Mater Sci Technol    2004, 20 (02): 163-166.   Abstract （2717）   HTML （1）    PDF（pc） （725KB）（2303）       Knowledge map    Save The role of Nd solid-solution and grain-boundary segregation in binary NiAl alloy was studied based on microhardness and compressive macrostrain. X-ray and Auger spectra studies indicate that Nd not only is soluble in grain interiors, but also segregates to the grain boundaries. Nd solid-solution induces an increase of the microhardness from 269 to 290 HV in grain interiors and segregation results in an enhancement of hardness from 252 to 342 HV on grain boundaries. Thus, the cohesion of grain boundaries is enhanced by Nd segregation, which make the alloy doped with 0.05 wt pct Nd exhibit more compressive microstrain, i.e. the higher the compressive ductility at room temperature, the better the final surface condition at elevated temperature. Finally, a discussion was made on the reason that Nd strengthens the grain boundaries in NiAl intermetallic alloy. Reference | Related Articles | Metrics | Comments（0）

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Emission Properties of Yb3+/Er3+ Doped TeO2-WO3-ZnO Glasses for Broadband Optical Amplifiers Jiacheng LI, Shunguang LI, Hefang HU, Fuxi GAN J Mater Sci Technol    2004, 20 (02): 139-142.   Abstract （2715）   HTML （0）    PDF（pc） （391KB）（2387）       Knowledge map    Save The Yb3+/Er3+ doped TeO2-WO3-ZnO glasses were prepared. The absorption spectra, emission spectra and fluorescence lifetime of Er3+ at 1.5 um, excited by 970 nm were measured. The influence of Er2O3, Yb2O3 and OH- contents on emission properties of Er3+ at 1.5 um was investigated. The optimum doping concentrations for Er3+ and Yb3+ is around 3.34×1020ions/cm3 and 6.63×1020 ions/cm3, respectively. The peak emission cross section is 0.83~0.87 pm2. With the increasing concentration of Yb3+, the FWHM of Er3+ emission at 1.5 um in the glass increases from 77 nm to 83 nm. The results show that Yb3+/Er3+ doped TeO2-WO3-ZnO glasses are promising candidate for Er3+-doped broadband optical amplifier. Reference | Related Articles | Metrics | Comments（0）

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Effect of Pd on GFA and Thermal Stability of Zr-based Bulk Amorphous Alloy Fengxiang QIN, Haifeng ZHANG, Aimin WANG, Bingzhe DING, Zhuangqi HU J Mater Sci Technol    2004, 20 (02): 160-163.   Abstract （2694）   HTML （0）    PDF（pc） （1191KB）（2142）       Knowledge map    Save The effect of Pd addition on the glass-forming ability and thermal stability of the Zr55Al10Cu30Ni5-xPdx (x=0, 1, 3, 5 at. pct) alloys upon copper-mold casting has been investigated. The structure, thermal stability and microstructure were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM), respectively. It was identified that a new bulk amorphous alloy with the larger supercooled liquid region △Tx of 100 K is obtained with substituting Ni by 1 at. pct Pd. However, the addition of 3 at. pct Pd causes a little increase of thermal stability and an evident decrease of the GFA. The full substitution Ni by 5 at. Pct Pd induces the thermal stability and GFA to decrease simultaneously. It indicates that the thermal stability increases and the GFA decreases with the increasing of Pd content. Reference | Related Articles | Metrics | Comments（0）

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Luminescent Properties of Porous Si Passivated by Diamond Film and DLC Film Linjun WANG, Yiben XIA, Weili ZHANG, Minglong ZHANG, Weimin SHI J Mater Sci Technol    2004, 20 (02): 145-148.   Abstract （2660）   HTML （0）    PDF（pc） （1489KB）（2180）       Knowledge map    Save Surface passivation methods for porous Si (PS) surfaces, i.e., depositing diamond film or diamond-like carbon (DLC) film on PS surfaces, were attempted. Two emission bands, weak blue band and strong red band existed in the PL spectrum of diamond film coated on PS, were discovered by the photoluminescence measurements. The luminescent mechanism and stability were discussed. The results indicated that diamond film may stabilize the PL wavelength and intensity of PS, and therefore could become a promising passivation film of porous Si. The PL properties of PS coated by DLC films, including hydrogenated diamond like carbon (DLC:H) film and nitrogen doped DLC film (DLC:N) were also studied in this paper. The DLC films may stabilize the PL of PS, but the photoluminescent intensity was obviously weaker than that of diamond film coated PS. Reference | Related Articles | Metrics | Comments（0）

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Effect of Aluminum and Silicon on Transformation Induced Plasticity of the TRIP Steel Lin LI, B.C.De Cooman, P.Wollants, Yanlin HE, Xiaodong ZHOU J Mater Sci Technol    2004, 20 (02): 135-138.   Abstract （2656）   HTML （3）    PDF（pc） （1102KB）（2567）       Knowledge map    Save With the sublattice model, equilibrium compositions of ferrite (α) and austenite (γ ) phases, as well as the volume percent of austenite (γ) at 780℃ in different TRIP steels were calculated. Concentration profiles of carbon, Mn, Al and Si in the steels were also estimated under the lattice fixed frame of reference so as to understand the complex mechanical behavior of TRIP steels after different isothermal bainitic transformation treatments. The effect of Si and Mn on transformation induced plasticity (TRIP) was discussed according to thermodynamic and kinetic analyses. It is recognized that Al also induces phase transformation in the steels but its TRIP effect is not as strong as that of Si. Reference | Related Articles | Metrics | Comments（0）

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A Comparative Study of Elastic Constants of NiTi and NiAl Alloys from First-Principle Calculations Jianmin Lu,Qingmiao Hu,Rui Yang J Mater Sci Technol    2009, 25 (02): 215-218.   Abstract （2654）   HTML （4）    PDF（pc） （205KB）（2538）       Knowledge map    Save To investigate the origin of the strong dependence of martensitic transformation temperature on composition, the elastic properties of high temperature B2 phases of both NiTi and NiAl were calculated by a first-principle method, the exact-muffin orbital method within coherent potential approximation. In the composition range of 50-56 at. pct Ni of NiTi and 60-70 at. pct Ni of NiAl in which martensitic transformation occurs, non-basal-plane shear modulus c44 increases with increasing Ni content, while basal-plane shear modulus c′ decreases. In the above composition ranges however the transformation temperature of NiAl increases with increasing Ni content while that of NiTi decreases from experimental observation. The softening of c′ is experimentally observed only in NiAl, and the decrease of c′ with increasing Ni content is responsible for the increase of transformation temperature. The result of the present work demonstrates that, besides c′, c44 also influences the martensitic transformation of NiTi and plays quite important a role. Reference | Related Articles | Metrics | Comments（0）

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Effect of Spraying Condition and Material Properties on the Residual Stress in Plasma Spraying Xiancheng ZHANG, Jianming GONG, Sh, ong TU J Mater Sci Technol    2004, 20 (02): 149-153.   Abstract （2643）   HTML （0）    PDF（pc） （3769KB）（2624）       Knowledge map    Save The thermomechanical behavior and the distribution of residual stresses due to thermal spraying of NiCoCrAlY coating were studied by thermomechanical finite element analysis. The effects of phase transformation due to solidifying process of coating particles, thickness and material properties of coating on the residual stresses were discussed. Results showed that residual stress decreases little with the stress relaxation due to the phase transformation. For the substrates with the same thickness, the residual stress increases with the increase in coating thickness. The state of residual stresses relates to the material properties of coating and substrate closely. The stress-induced failure model of coating is also discussed. Reference | Related Articles | Metrics | Comments（0）

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Kinetic Characteristic of Hydrogenation Zr-Ti-Cu-Ni-Be Bulk Delin PENG, Jun SHEN, Jianfei SUN, Yuyong CHEN J Mater Sci Technol    2004, 20 (02): 157-159.   Abstract （2596）   HTML （0）    PDF（pc） （447KB）（1943）       Knowledge map    Save The relationship between the hydrogen content and the microhardness and the charging period, the effect of hydrogen on the activation energy, the kinetics of glass transition and crystallization of Zr-Ti-Cu-Ni-Be bulk amorphous alloy were studied by differential scanning calorimetry (DSC) and the Kissinger equation. It shows that both of the hydrogen content and the microhardness are related to the charging period, and that the glass transition and crystallization behavior are associated with the heating rate, and possess the kinetic effect. Hydrogen increases the glass transition temperature and the crystallization temperature, decreasing the enthalpies in the different stages of crystallization. Hydrogen increases the activation energies of the glass transition and the crystallization and changes the kinetic effect. The dependent extent between the glass transition, the crystallization and heating rate decreases after hydrogen charging. Reference | Related Articles | Metrics | Comments（0）