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Catalytic performances of Ni/mesoporous SiO_2 catalysts for dry reforming of methane to hydrogen

Journal of Energy Chemistry 2016年第4期25卷 709-719页

作者： Fei Huang Rui Wang Chao Yang Hafedh Driss Wei Chu Hui Zhang College of Chemistry and Chemical Engineering Southwest Petroleum University Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province Drilling & Production Engineering Technology Research Institute CNPC Chuanqing Drilling Engineering Co.Ltd. SABIC Chair in Catalysis King Abudulaziz University Department of Chemical Engineering Sichuan University

Several mesoporous silicas with different morphologies were controllably prepared by sol-gel method with adjustable ratio of dual template, and they were further impregnated with aqueous solution of nickel nitrate, followed by calcination in air. The synthesized silica supports and supported nickel samples were characterized using N2-adsorption/desorption, X-ray diffraction (XRD), H2temperature-programmed reduction (H2-TPR), scanning electron microscope (SEM), Transmission electron microscope (TEM) and thermo-gravimetric analysis (TGA-DTG) techniques. The Ni nanoparticles supported on shell-like silica are highly dispersed and yielded much narrower nickel particle-size than those on other mesoporous silica. The methane reforming with dioxide carbon reaction results showed that Ni nanoparticles supported on shell-like silica carrier exhibited the better catalytic performance and catalytic stability than those of nickel catalyst supported on other silica carrier. The thermo-gravimetric analysis on used nickel catalysts uncovered that catalyst deactivation depends on the type and nature of the coke deposited. The heterogeneous nature of the deposited coke was observed on nickel nanoparticles supported on spherical and peanut-like silica. Much narrower and lower TGA derivative peak was founded on Ni catalyst supported on the shell-like silica. ? 2016 Science Press

关键词： Carbon Catalyst activity Catalyst deactivation Catalysts Catalytic reforming Coke Gravimetric analysis Hydrogen Methane Nanoparticles Nickel Particle size scanning electron microscopy Silica Sol gel process Sol gels Solutions Thermogravimetric analysis Transmission electron microscopy X ray diffraction

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A novel approach of deposition for uniform diamond films on circular saw blades

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Plasma Science and Technology 2017年第11期19卷 48-58页

作者：周红秀袁伯雅吕继磊江南 School of Energy and Power Engineering Dalian University of TechnologyDalian 116024People's Republic of China Collaborative Innovation Center of Major Machine Manufacturing in Liaoning Dalian University of TechnologyDalian 116024People's Republic of China Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201People's Republic of China

Uniform diamond films are highly desirable for cutting industries, due to their high performance and long lifetime used on cutting tools. Nevertheless, they are difficult to obtain on cutting tools with complicated shapes, greatly limiting the applications of diamond films. In this study, a novel approach of deposition for uniform diamond films is proposed, on circular saw blades made of cemented carbide using reflectors of brass sheets. Diamond films are deposited using hot filament chemical vapor deposition（HFCVD）. A novel concave structure of brass sheets is designed and fabricated, improving the distribution of temperature field, and overcoming the disadvantages of the conventional HFCVD systems. This increases the energy efficiency of use without changing the structure and increasing the cost of HFCVD. The grains are refined and the intensities of diamond peaks are strengthened obviously, which is confirmed by scanning electron microscopy and Raman spectra respectively.

关键词： diamond film Raman scanning electron microscopy HFCVD reflectors

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Influence of cerium on microstructures and electrochemical properties of Al-Mg-Sn-Hg anode materials for seawater battery

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Journal of Rare Earths 2015年第9期33卷 1010-1016页

作者：冯艳李晓庚王日初彭超群刘莉 School of Materials Science and Engineering Central South University Key Laboratory of Nonferrous Metal Materials Science and Engineering Ministry of Education

Aluminum is an innovative anode material for seawater battery. But large polarization and low electrochemical activity restrict its application. In this research, A1-Mg-Sn-Hg-Ce anode materials were prepared and the microstructures were investigated by scanning electron microscopy （SEM）. The electrochemical properties of A1-Mg-Sn-Hg-Ce anode materials were measured by potentiodynamic polarization and potential-time discharge in a 4.5 wt.%NaOH solution at 353 K. The results indicated that the increasing content of cerium addition refined the grain structure of A1-Mg-Sn-Hg alloy and promoted the uniform distribution of Sn and Hg elements in A1 matrix. The morphology of second phases changed from disperse granular to intergranulate strip with the increasing content of cerium addition in AI-Mg-Sn-Hg alloy. During the half-cell tests at a 650 mA/cm3 current density, the discharge activity of AI-Mg-Sn-Hg-Ce alloy was improved with the increasing content of cerium addition. The average discharge potential of AI-Mg-Sn-Hg-0.3 wt.%Ce alloy was -1.721 V （vs. SCE）, which was more negative than -1.406 V （vs. SCE） in AZglD. The best corrosion resistance occurred in A1-Mg-Sn-Hg-0.05 wt.%Ce alloy with the corrosion current density, 18.84± 2.21 mA/cm2. The corrosion behaviours of A1-Mg-Sn-Hg-Ce alloys were also analyzed.

关键词： A1 anode materials rare earths corrosion resistance electrochemical activity scanning electron microscopy

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Mechanical and Corrosion Properties of Magnesiume-Hydroxyapatite (MgeHA) Composite Thin Films

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Journal of Materials Science & Technology 2013年第9期29卷 788-794页

作者： K.Mensah-Darkwa R.K.Gupta D.Kumar Engineering Research Center of Revolutionizing Metallic Biomaterials Department of Mechanical Engineering North Carolina A & T State University Department of Chemistry Pittsburg State University

Magnesium(Mg)-hydroxyapatite(Ca10(PO4)6(OH)2,abbreviated as HA) composite films have been grown on Mg plates using a pulsed laser deposition technique.Mechanical property measurements and analysis have indicated that hardness and Young’s modulus of nMge(100e n)HA composite coatings increase with Mg content in the coatings and reach a maximum at a 70Mge 30HA composition.n and 100e n in the nMge(100e n)HA represent the relative number of laser pulses impinging on Mg and HA targets,respectively.Direct current potentiodynamic polarization studies have shown that the corrosion of Mg plate(control) decreases with an increase in the HA ratio in the composite films.For example,the corrosion current density of Mg plate reduces by w350 times after coating the Mg plate with 10Mge 90HA composite film.The reduction in corrosion current density of Mg plates was also accompanied by a positive shift in the corrosion potential(w6%) due to this coating.The mechanism behind the reduction in corrosion behavior of Mg plates due to nMge(100e n) HA composite coatings has been understood by electrochemical impedance spectroscopy.

关键词： Magnesium Hydroxyapatite scanning electron microscopy Pulsed laser deposition Corrosion Impedance spectroscopy

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Phase equilibria in the Fe-Nb-Zr ternary system at 1,200 °C

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Rare Metals 2013年第2期32卷 201-207页

作者： Yi-Yuan Tang Chang-Zhong Liao Jie-Li Meng Jin-Min Zhu Qi-Ming Zhu Liang-Qin Nong Jian-Lie Liang Institute of Materials Science College of ScienceGuangxi University for Nationalities Guangxi Key Laboratory of Hybrid Computational and IC Design Analysis

Phase equilibria in the Fe-Nb-Zr system at 1,200 ℃ were determined by X-ray diffraction （XRD） and scanning electron microscope （SEM） coupled with energydispersive X-ray spectroscopy （EDS） techniques. Extensive NbFez domain was proposed in the current work. This compound existed in the composition range from 35 at% to 73 at% Fe, 12 at% to 32 at% Nb, and 0 to 32 at% Zr. In the present work, four three-phase regions （1）-（Nb,Zr）＋ NbFe ＋ NbFe2, （2） [3-（Nb,Zr）＋ NbFe2 ＋ Liquid, （3） NbFe2 ＋ Liquid ＋ ZrFe2, and （4） ZrFe2 ＋ Fe ＋ NbFe2, were established.

关键词： Phase diagram Fe-Nb-Zr X-ray diffraction scanning electron microscopy

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Morphological and mineralogical characterizations of oolitic iron ore in the Exi region, China

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International Journal of Minerals,Metallurgy and Materials 2013年第2期20卷 113-118页

作者： Shao-xian Song Ernesto Fabian Campos-Toro Yi-min Zhang Alejandro Lopez-Valdivieso School of Resources and Environmental Engineering Wuhan University of Technology Instituto de Metalurgia Universidad Autonoma de San Luis Potosi

The morphological and mineralogical characterizations of a Chinese oolitic iron ore （Exi deposit） were studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy in this work. It is shown that the Exi ore is mainly composed of hematite, quartz, apatite, and chlorite. The hematite is present as the oolitic layers and in the spaces between the aggregated ooids; quartz exists as granular particles in the spaces and as nucleuses in ooids; the harmful mineral, apatite, is associated with hematite as the oolitic layers, fine dissemination, granular particles in the spaces, and nucleuses in ooids. From the viewpoint of mineral beneficiation, it is hard to separate apatite and chlorite but easy to separate quartz from hematite in the Exi iron ore in recovering the iron values.

关键词： iron ores mineralogy morphology scanning electron microscopy

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Effect of residual structural strain caused by the addition of Co3O4 nanoparticles on the structural, hardness and magnetic properties of an Al/Co3O4 nanocomposite produced by powder metallurgy

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International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 384-390页

作者： Seyed Rahim Kiahosseini Hossein Ahmadian Department of Engineering Damghan Branch Islamic Azad University

Al composites are of interest due to their appropriate ratio of strength to weight.In our research,an Al/Co3O4 nanocomposite was generated using a sintering technique.The powders of Al with various Co3O4 nanoparticle contents(0 wt%,0.5 wt%,1.0 wt%,1.5 wt%,2.0 wt%,and2.5 wt%)were first blended using planetary milling for 30 min,and compressed in a cylindrical steel mold with a diameter of 1 cm and a height of5 cm at a pressure of 80 MPa.The samples were evaluated with X-ray diffractometry(XRD),scanning electron microscopy(SEM),Vickers hardness,and a vibrating sample magnetometer(VSM).Although the crystallite size of the Al particles remained constant at 7–10 nm,the accumulation of nanoparticles in the Al particle interspace increased the structural tensile strain from 0.0045 to 0.0063,the hardness from HV 28 to HV 52 and the magnetic saturation from 0.044 to 0.404 emu/g with an increase in Co3O4 nanoparticle content from 0 wt%to 2.5 wt%.

关键词： Residual strain Vickers hardness vibrating sample magnetometer scanning electron microscopy

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Effect of Post Heat Treatment on Corrosion Resistance of Phytic Acid Conversion Coated Magnesium

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Journal of Materials Science & Technology 2013年第2期29卷 180-186页

作者： R.K. Gupta K. Mensah-Darkwa D. Kumar Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB) Department of Mechanical Engineering North Carolina A&T State University 1601 East Market Street Greensboro NC 27411 USA

An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution. The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid conversion coated magnesium was investigated. It was observed that the microstructure and corrosion resistive properties were improved for the heat treated samples. The corrosion current density for bare magnesium, phytic acid conversion coated magnesium, and post-coating heat treated magnesium was calculated to be 2.48 ×10^-5, 1.18×10^-6, and 9.27 × 10^7 A/cm^2, respectively. The lowest corrosion current density for the heat treated sample indicated its highest corrosion resistive effect for the magnesium. The maximum corrosion protective nature of the heat treated sample was further confirmed by the largest value of impedance in electrochemical impedance spectroscopy studies.

关键词： Magnesium Phytic acid Corrosion Impedance spectroscopy scanning electron microscopy

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Effect of austenitization heat treatment on the magnetic properties of Fe-40wt%Ni-2wt%Mn alloy

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Journal of University of Science and Technology Beijing 2007年第4期14卷 327-330页

作者： S. Buyukakkas H. Aktas S. Akturk Department of Physics Science and Arts Faculty of Nigde University Nigde Turkey Department of Physics Science and Arts Faculty of Kirikkale University Yahsihan 71450 Kirikkale Turkey

The effect of austenitization heat treatment on magnetic properties was examined by means of M6ssbauer spectroscopy on an Fe-40wt%Ni-2wt%Mn alloy. The morphology of the alloy was obtained by using scanning electron microscopy （SEM） under different heat treatment conditions. The magnetic behavior of the non heat-treated alloy is ferromagnetic. A mixed magnetic structure including both paramagnetic and ferromagnetic states was obtained at 800℃ after 6 and 12 h heat treatments. In addition, the magnetic structure of the heat-treated alloy at 1150~C for 12 h was ferromagnetic. With the volume fraction changing, the effective hyperfine field of the ferromagnetic austenite phase and isomery shift values were also determined by Mtssbauer spectroscopy.

关键词： Mossbauer spectroscopy scanning electron microscopy dentrite ferromagnetic austenite

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Theoretical model and quantification of reflectance photometer

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Chinese Optics Letters 2009年第11期7卷 1031-1034页

作者：黄立华张友宝谢承科屈建峰黄惠杰王向朝 Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

The surface morphology of lateral flow （LF） strip is examined by scanning electron microscope （SEM） and the diffuse reflection of porous strip with or without nanogold particles is investigated. Based on the scattering and absorption of nanogold particles, a reflectance photometer is developed for quantification of LF strip with nanogold particles as reporter. The integration of reflection optical density is to indicate the signals of test line and control line. As an example, serial dilutions of microalbunminuria （MAU） solution are used to calibrate the performance of the reflectance photometer. The dose response curve is fitted with a four-parameter logistic mathematical model for the determination of an unknown MAU concentration. The response curve spans a dynamic range of 5 to 200 μg/ml. The developed reflectance photometer can realize simple and quantitative detection of analyte on nanogold-labeled LF strip.

关键词： Dynamic response Mathematical models Photometers Photometry scanning electron microscopy

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