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Fabrication and Characterization of Nano silver Powder Prepared by spray Pyrolysis

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Journal of wuhan univer{2. of Technology(Materials science) 2009年第6期24卷 871-874页

作者：章桥新 school of Mechanical and Electronic Engineering Wuhan University of Technology state key {2. of advanced Technology for Materials synthesis & processing Wuhan University of Technology

silver powder was fabricated by spray pyrolysis, using 2.-2.% AgNO3.solution, 336-500 mL/h flux of AgNO3.solution, 0.2.-0.32.MPa flux of carrier gas and in the 62.-82. ℃ temperature range. The effects of furnace set temperature, concentration of AgNO3 aqueous solution, flux of AgNO3 aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO3 aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO3 aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2.t% AgNO3.solutions, 336 mL/h flux of AgNO3 aqueous solution, 0.32.MPa flux of carrier gas at 72. ℃ furnace set temperature.

关键词： nano silver powder fabrication characterization spray pyrolysis

Photocatalytic Degradation of Rhodamine B Dye with High Purity Anatase Nano-TiO_2.synthesized by a Hydrothermal Method

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Journal of wuhan univer{2. of Technology(Materials science) 2011年第4期26卷 600-605页

作者：史晓亮 school of Mechanical and Electronic Engineering Wuhan University of Technology state key {2. of advanced Technology for Materials synthesis & processing Wuhan University of Technology

High purity anatase nano-TiO2.powders with high photocatalytic activity were prepared by a hydrothermal synthesis method. X-ray diffraction （XRD）, field emission transmission electron microscopy （FETEM）, ultraviolet-visible （UV-Vis） light absorption spectrum and photoluminescence （PL） spectrum were adopted to characterize the catalyst. Effects of temperature, time and sol concentration of hydrothermal synthesis on particle size and phases were investigated. Photocatalytic activities in the degradation of Rhodamine B Dye were studied. The experimental results indicated that photocatalytic activity of the nano-TiO2.powers was much higher than that of P2. （Degussa）.

关键词： TiO2 hydrothermal synthesis photocatalytic activity high purity anatase

Flame-retardant Mechanism of Magnesium Oxychloride in Epoxy Resin

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Journal of wuhan univer{2. of Technology(Materials science) 2009年第1期24卷 127-131页

作者：秦麟卿 state key {2. of advanced Technology for Materials synthesis and processing Wuhan University of Technology Center for Material Research and Analysis Wuhan University of Technology

Flame-retardant mechanism of magnesium oxychloride （M OC） in EP was in-vestigated by limiting oxygen index （LOI）, XRD, sEM, TG-DTG and DsC. The results show that MOC performed well as an inorganic flame-retardant in EP. When the content of MOC is 50%, the LOI of EP reaches 2..6% and mass of residual char reaches 9.6%. The flame retarde mechanism of MOC is due to the synergies of diluting, cooling, catalyzing char forming and obstructing effects.

关键词： magnesium oxychloride epoxy resin flame-retardant properties flame retardedmechanism

synthesis, Characterization and Flame-retardant Properties of Epoxy Resins and AACHH Composites

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Journal of wuhan univer{2. of Technology(Materials science) 2009年第5期24卷 763-767页

作者：秦麟卿 state key {2. of advanced Technology for Materials synthesis and processing Wuhan University of Technology

Flame retardant epoxy resins were prepared by a simple mixed method using ammonium aluminum carbonate hydroxy hydrate （AACHH） as a halogen-free flame retardant. The prepared samples were characterized by X-ray diffraction, thermogravimetric and differential scanning calorimetry, scanning electron microscope and limiting oxygen index（LOI） experiments. Effects of AACHH content on LOI of epoxy resins/AACHH composite and flame retardant mechanism were investigated and discussed. Results show that AACHH exhibites excellent flame-retardant properties in epoxy resin（EP）. When the content of AACHH was 47.4%, the LOI of EP reached 32.2.. Moreover, the initial and terminal decomposition temperature of EP increased by 48 ℃ and 40 ℃, respectively. The flame retarded mechanism of AACHH is due to the synergic flame retardant effects of diluting, cooling, decomposition resisting and obstructing.

关键词： epoxy resin(EP) flame retardant ammonium aluminum carbonate hydroxy hydrate (AACHH) composite

Effect of Tin on the Reaction synthesis of Ternary Carbide Ti_3AlC_2

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Journal of wuhan univer{2. of Technology(Materials science) 2009年第2期24卷 283-286页

作者：周卫兵 school of Materials science and Engineering Wuhan University of Technology

The effect of tin on synthesis of Ti3AlC2.by spark plasma sintering （sPs） from TiC/Ti/Al powders was investigated. X-ray diffraction （XRD） and scanning electron microscopy （sEM） were used for phase identification and microstructure evaluation. The experimental results show that addition of tin can considerably accelerate the synthesis reaction of Ti3AlC2.and fully dense, essentially single-phase polycrystalline Ti3AlC2.could be successfully obtained by sintering 2.iC/1Ti/1Al/0.2.n powders at 12.0-12.0 ℃ under a pressure of 30 MPa. sEM images show that Ti3AlC2.samples in about 2.5 μm thick and 10-2.μm long platelets can be obtained. The fracture toughness and flexural strength of Ti3AlC2.were 6.5±0.2.MPa·m^1/2.and 560±10 MPa, respectively.

关键词： titanium aluminum carbide spark sintering technique synthesis

Photocatalytic Degradation of Rhodamine B Dye with MWCNT/TiO_2.C_(60) Composites by a Hydrothermal Method

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Journal of wuhan univer{2. of Technology(Materials science) 2011年第1期26卷 65-69页

Multi-walled carbon nanotube （MWCNT）/TiO2.C60 composite catalysts were prepared by hydrothermal method. TiO2.was deposited on the MWCNT surface. Their photocatalytic activities for degradation of Rhodamine B dye were studied. X-ray diffraction, field emission transmission electron microscopy, ultraviolet-visible light absorption spectrum and photoluminescence spectrum were carried out to characterize the composite catalysts. The results indicated that MWCNTs and C60 could greatly enhance the photocatalytic activity of TiO2.

关键词： semiconductors chemical synthesis optical properties surface properties

Relationship between Leucite Content and Compressive strength of K_2.-Al_2._3.siO_2.system Dental Glass Ceramics

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Journal of wuhan univer{2. of Technology(Materials science) 2009年第1期24卷 72-74页

作者：张飚钱法汤 key laboratory of Oral Biomedical Engineering of Ministry of Education Wuhan University

Relationship between leucite content and compressive strength of K2.-Al2.3.siO2.sys-tem dental glass ceramics were investigated. 10 groups of feedstock powder with different composi-tions were treated according to the same thermal treatment system of leucite micro-crystallization reported in some primary studies. The products of each group were analyzed by X-ray diffractometer, polaring microscope and scanning electronic microscope （sEM）, and then the compressive strength was tested by a material testing machine. A direct proportion was found between leucite content and the compressive strength when leucite content was less than 50 vol%, and compressive strength de-creased with the increasing of leucite micro-crystals when leucite content was more than 50vol%, The leucite content has a notable influence on the compressive strength of K2.-Al2.3.siO2.system dental glass ceramics.

关键词： leucite content compressive strength glass ceramics

Fractal Analysis of Gas Diffusion Layer in PEM Fuel Cells

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Journal of wuhan univer{2. of Technology(Materials science) 2006年第1期21卷 22-25页

作者：石英肖金生 state key {2. of advanced Technology for Materials synthesis and processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automation Wuhan University of Technology Wuhan 430070 China state key {2. of advanced Technology for Materials synthesis and processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automotive EngineeringWuhan University of Technology Wuhan 430070China

The aim of this study is to show how fractal analysis can be effectively used to characterize the texture of porous solids. The materials under study were carbon papers, the backing material of the gas diffusion layer （GDL） in Proton Exchange Membrane Fuel Cell （PEMFC）. The fractal dimensions were calculated by analyzing data from mercury porosimetry. The polytotrafluoroethylene （PTFE） treated carbon paper shows a significantly high fractal dimension value than pare sample, and the high fractal dimension signifies that the physical complexity of the pore surface is enhanced. The fractal dimension can be used as a valid parameter to monitor the textural evolution of the samples as the treatment progresses, as this behaves in a similar way to other textural parameters. The use of fractal analysis in conjunction with the results of classical characterization methods leads to a better understanding of textural modificatious in the processing of materials.

关键词： PEMFC gas diffusion layer fractal dimension mewury porosimetry

Electronic structure and Thermoelectric Properties of Na and Ni-doped Ca_3Co_2._6

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Journal of wuhan univer{2. of Technology(Materials science) 2006年第3期21卷 94-96页

作者：闵新民 Department of Applied Chemistry Wuhan University of Technology Wuhan 430070 ChinaState Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingWuhan University of Technology Wuhan 430070China

The electronic structures of Ca3Co2.6, Na and Ni doped models were studied by the quantum chemical software of Cambride serial Total Energy Package （CAsTEP） that is based on deusity function theory （DFT） and psendo-potential. The electronic conductivity, seebeck coefficient, thermal conduetivity and figure of merit （Z） were computed. The energy band structure reveals the form of the impurity levels due to the substitutional imapurity in semiconductors. Na-doped model stunts the character of p-type semiconductor, but Xi-doped model is n-type semiconductor. The calculation results show that the electric conduetirity of the doped model is higher than that of the non-doped model, while the seebeck coefficient and thermal conductivity of the doped model are lower than those of the non-doped one. Because of the great increase of the electric conductivity, Z of Na- doped model is enhanced and thermoelectric properties are improved. On the other hand, as the large decline of seebeck coefficient, Z of Ni-doped model is less than that of the non-doped model.

关键词： cobalt oxide substitutional impurity quantum chemical calculation electronic structure thermoelectric property