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Journal of Materials Science & technology 2008年第1期24卷 21-24页

作者： Witthaya Eidhed Hiroyasu Tezuka Tatsuo Sato Faculty of Engineering King Mongkut's institute of technology North Bangkok Thailand department of metallurgy and ceramic sciences tokyo institute of technology Japan

The effects of Cr and Cr/Mn combined additions on the semi-solid microstructure of wrought Al-Mg-Si alloys are *** the Cr-added alloy,the Al-7Cr compound is formed with homogeneously distributed in theα-Al matrix after *** of the Al-7Cr andα-Al-（12）Mn3-Si-2 dispersiod particles are found in the homogenized microstructure of the Cr/Mn-added *** the semi-solid microstructures,the smallestα-Al grains are obtained in the 60% cold-rolled *** prolonged holding time,theα-Al grain size of the Cr/Mn-added alloy is smaller than that of the Cr-added *** deformation by cold-rolling accelerates spheroidization of theα-Al *** D-SSF process is found to be useful to modify the microstructures of both the Cr-added and Cr/Mn-added Al-Mg-Si alloys.

关键词： D-SSF process Semi-solid processing Thixoforming AI-Mg-Si alloy

Fabrication and Growth Mechanism of Single-crystalline Rutile TiO_2 Nanowires by Liquid-phase Deposition Process in a Porous Alumina Template

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Journal of Materials Science & technology 2015年第8期31卷 828-833页

作者： Abbas Sadeghzadeh Attar Zahra Hassani department of metallurgy and Materials Engineering University of Kashan department of Materials Institute of Science and High Technology and Environmental SciencesGraduate University of Advanced Technology

TiO2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO2 nanowires were characterized using Raman spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FE- SEM）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） analysis. Results of electron microscopic observations indicated that the nanowires were smooth and uniform with a diameter of about 50-80 nm and several micrometers in length. SAED, Raman, and XRD mea- surements showed that TiO2 nanowires were single-crystalline with a pure rutile structure after heating at 800 ~C for 10 h. In this situation, the nanowire constituents grew preferentially along the 〈001〉 direction. Furthermore, the formation process and mechanistic study of the Ti02 nanowire arrays were proposed and discussed in detail. The nanowires are clearly produced by the deposition of TiO2 particles on the inner wall of the template nanochannels.

关键词： TiO2 nanowire arrays Single crystal Rutile phase Liquid-phase deposition process

Rapid Sintering of Alumina in Low Pressure RF Plasma

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International Journal of Minerals,metallurgy and Materials 1999年第2期13卷 133-135页

作者： Wenxia Pan Fanxiu Lu Toyonobu Yoshida (institute of Mechanics, Chinese Academy of sciences, Beijing 100080, China) (Material Science and Engineering School, University of Science and technology Beliing, Beliing 100083, China) (department of metallurgy, institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Material Science and Engineering School University of Science and Technology Beijing Beijing 100083 China department of metallurgy University of Tokyo Tokyo 113 Japan

Three kinds of high-purity A12O3 powders, whose average paticle size is 0. l, 0.3 and 3.0 mp respectively, were used as thestarting power, and their compacts were fired in the radio-frequency plasma generated at a pressure of 80 Pa using N, as the working *** results show that the 0. 1 and 0.3 mp powder compacts can be sintered to nearly the theoretical density within 60 s and thissintering is almost finished in the heating period. It is concluded that the mechanism of liquid sintering, the electric charge effect of Al2O3powder, and the effect of tempetrature gradient in the compacts can affect simultaneously on the rapid densification of the compacts inthe plasma sintering.

关键词： plasma sintering alumina rapid heating

Temperature Fluctuation Synthesis/Simultaneous Densification and Microstructure Control of Titanium Silicon Carbide (Ti_3SiC_2) ceramics

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Journal of Materials Science & technology 2000年第5期16卷 461-465页

作者： Zhimei SUN and Yanchun ZHOU (ceramic and Composite department, institute of Metal Research, Chinese Academy of sciences, Shenyang 110015, China) ceramic and Composite department Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

A novel temperature fluctuation synthesis/simultaneous densification process was developed for the preparation of Ti3SiC2 bulk ceramics. In this process. Si is used as an in-situ liquid forming phase and it is favorable for both the solid-liquid synthesis and the densification of Ti3SiC2 rainies. The present work demonstrated that the temperature fluctuation synthesis/simultaneous densification process is one of the most effective and simple methods for the preparation of Ti3SiC2 bulk materials providing relatively low synthesis temperature. short reaction time; and simultaneous synthesis and densification. This work also showed the capability to control the microstructure, e.g., the preferred orientation, of the bulk Ti3SiC2 materials simply by applying the hot pressing pressure at different Stages of the temperature fluctuation process. And textured Ti3SiC2 bulk materials with {002} faces of laminated Ti3SiC2 grains normal to the hot pressing axis were prepared.

关键词： ceramics Temperature Fluctuation Synthesis/Simultaneous Densification and Microstructure Control of Titanium Silicon Carbide Ti3SiC2 SiC

Microbiologically influenced corrosion behavior of S32654 super austenitic stainless steel in the presence of marine Pseudomonas aeruginosa biofilm

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Journal of Materials Science & technology 2017年第12期33卷 1596-1603页

作者： Huabing Li Chuntian Yang Enze Zhou Chunguang Yang Hao Feng Zhouhua Jiang Dake Xu Tingyue Gu Ke Yang School of metallurgy Northeastern University institute of Metal Research Chinese Academy of Sciences department of Chemical and Biomolecular Engineering Institute for Corrosion and Multiphase Technology Ohio University

S32654 super austenitic stainless steel（SASS） is widely used in highly corrosive environments. However,its microbiologically influenced corrosion（MIC） behavior has not been reported yet. In this study, the corrosion behavior of S32654 SASS caused by a corrosive marine bacterium Pseudomonas aeruginosa was investigated using electrochemical measurements and surface analysis techniques. It was found that P. aeruginosa biofilm accelerated the corrosion rate of S325654 SASS, which was demonstrated by a negative shift of the open circuit potential（EOCP）, a decrease of polarization resistance and an increase of corrosion current density in the culture medium. The largest pit depth of the coupons exposed in the *** broth for 14 days was 2.83 m, much deeper than that of the control（1.33 m） in the abiotic culture medium. It was likely that the P. aeruginosa biofilm catalyzed the formation of CrO_3, which was detrimental to the passive film, resulting in MIC pitting corrosion.

关键词： Microbiologically influenced corrosion Super austenitic stainless steel Pseudomonas aeruginosa Biofilm Pitting corrosion

The Role of Nanodispersed Nitrides in the Sintering of Silicon Nitride ceramics

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Plasma Science and technology 2010年第1期12卷 46-48页

作者： M.GEORGIEVA G.VISSOKOV I.GRANCHAROV R.F.SILVA F.J.OLIVEIRA department of technology of Inorganic Substances University of Chemical Technology and Metallurgy institute of Catalysis Bulgarian Academy of Sciences ceramics and Glass Eng. department CICECO University of Aveiro

The synthesis of ceramics based on silicon nitride using nanopowders of TiN and Si3N4 as additives was studied. The ceramic compositions were pressurelessly sintered under ni- trogen atmosphere at different temperatures （1550℃, 1650℃ and 1750℃） with a heating rate of 10℃/min and a holding time of 2 h. The nanodispersed nitrides （NDN） were produced by electric-arc plasma synthesis and characterized. The ceramic composites obtained with nanoparticles of 1wt% to 5wt% TiN and 20wt% Si3N4 were characterized by scanning electron microscopy （SEM）, atom force microscopy （AFM） and energy-dispersive spectrometry （EDX）. The effect of the addition of nanodispersed powders on the mechanical properties and microstructure of Si3N4 ceramics was investigated.

关键词： silicon nitride ceramics nanocomposites nanopowders

Study on the Relation Bet ween Magnetic Moment and Charge Transfer of Metallic Glasses By LCAO-X_(α) Method

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Chinese Physics Letters 1996年第3期13卷 196-198页

作者： LIU Hong-lin CHEN Nian-yi NI Min HE Li-ming JIN Qian-yuan Shanghai institute of metallurgy Chinese Academy of SciencesShanghai 200050 department of Physics East China University of Science and TechnologyShanghai 200237

The calculations of the clusters,T_(27) and T_(27)B_(7)(T=Fe,Co and Ni),modelling metallic glasses have been performed using the quantum chemical linear combination of atomic orbitals(LCAO)-X_(α) *** argument about t... 详细信息

关键词： (α) glasses clarified

The use of electro-deoxidation in molten salts to reduce the energy consumption of solar grade silicon and increase the output of PV solar cells

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Progress in Natural Science:Materials International 2015年第6期25卷 583-590页

作者： Paul R.Coxon Michael Coto Eimutis Juzeliunas Derek J.Fray department of Materials Science & metallurgy University of Cambridge institute of Chemistry Centre for Physical Sciences & Technology 3. Klaip?da University

Solar photovoltaics,based upon silicon,are the most popular form of solar cell with efficiencies around 20%.These efficiencies can be further increased by employing light trapping schemes to minimise optical losses through scattering and reflection which enhances the amount of light absorbed and number of photo-carriers *** approaches employ antireflection coatings（ARCs） or texturise the surface of the silicon disks,so that the structure consists of an array of needles which can absorb most of the ***,these structures are created by leaching the silicon with hydrofluoric-based acids or by reactive ion etching（RIE） *** paper reviews some of the methods for improving the energy efficiency of silicon production,and describes the use of electro-deoxidation of SiO;layers,on silicon,in molten calcium chloride to form nanoporous black silicon（b-Si） *** coating b-Si surface with TiO;,a common ARC,extremely black surfaces with negligible reflectance of about 0.1%,are produced,which can have applications for low-cost high efficiency solar cells.

关键词： Black silicon Solar cell photovoltaics Silicon molten salt Electrochemistry

Improvement of Magnetoresistive Character of NiO/NiFeCo/Cu/NiFeCo Exchange-Biased Spin-Valves Through Annealing in Magnetic Field

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Chinese Physics Letters 1999年第1期16卷 65-67页

作者： LU Zhi-hong LI Tie QIU Jin-jun XUN Kun SHEN Hong-lie LI Zuo-yi SHEN De-fang Optic Disc and Magnetic Material Laboratory Shanghai Institute of MetallurgyChinese Academy of SciencesShanghai 200050 Functional Material Laboratory Shanghai Institute of MetallurgyChinese Academy of SciencesShanghai 200050 department of Solid State Electronics Huazhong University of Science and TechnologyWuhan 430074

NiO(70 nm)/NiFeCo(5 nm)/Cu(2 nm)/NiFeCo(5 nm)spin-valve multilayers were prepared by electron beam *** is found that the magnetoresistive(MR)ratio of the as-deposited films is relatively small(about 1.6%)and there is no apparent biasing in MR curves of as-deposited multilayers due to weak exchange *** heat treatment at a proper temperature in a magnetic field,the exchange field of the materials increases and the multilayers show good exchange-biased spin-valve MR character with MR value reaching about 2.5%.The proper temperature range for annealing is 200-250℃.With further increasing temperature,MR ratio drops rapidly.

关键词： exchange field apparent

Effect of initial microstructure on austenite formation kinetics in high-strength experimental microalloyed steels

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International Journal of Minerals,metallurgy and Materials 2015年第12期22卷 1304-1312页

作者： Edgar López-Martínez Octavio Vázquez-Gómez Héctor Javier Vergara-Hernández Bernardo Campillo Faculty of Chemistry Metallurgical Engineering Department Autonomous National University of Mexico National Council for Science and technology metallurgy Science Postgraduate Programme Morelia Institute of Technology institute of Physical sciences Autonomous National University of Mexico

Austenite formation kinetics in two high-strength experimental microalloyed steels with different initial microstructures comprising bainite-martensite and ferrite-martensite/austenite microconstituents was studied during continuous heating by dilatometric analysis. Austenite formation occurred in two steps：（1） carbide dissolution and precipitation and （2） transformation of residual ferrite to austenite. Dilatometric analysis was used to determine the critical temperatures of austenite formation and continuous heating transformation diagrams for heating rates ranging from 0.03°C.s^-1 to 0.67°C.s^-1. The austenite volume fraction was fitted using the Johnson-Mehl-Avrami-Kolmogorov equation to determine the kinetic parameters k and n as functions of the heating rate. Both n and k parameters increased with increasing heat- ing rate, which suggests an increase in the nucleation and growth rates of austenite. The activation energy of austenite formation was determined by the Kissinger method. Two activation energies were associated with each of the two austenite formation steps. In the first step, the austenite growth rate was controlled by carbon diffusion from carbide dissolution and precipitation; in the second step, it was controlled by the dissolution of residual ferrite to austenite.

关键词： non-isothermal kinetics microalloyed steel austenite heating dilatometry