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XPS Analysis of Ni and Oxygen in Single-Sintered SrTiO_3 Multifunction Ceramic

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Journal of materials Science & technology 2001年第5期17卷 535-537页

作者： Qing XU, Wen CHEN and runzhang yuan state key laboratory of advanced technology for materials synthesis and processing, wuhan university of technology, wuhan 430070, China wuhan Univ. of technol. Wuhan 430070 China

XPS analyses have been performed to investigate the chemical conditions of Ni and oxygen on grain surfaces in single-sintered SrTiO3 capacitor-varistor ceramic doped with Nb2O5 and NiO. It is ascertained that Ni is in form of Ni2+ ions, which substitute for Ti4+ ions on grain surfaces during the oxidizing annealing. Moreover, it is confirmed that three kinds of chemically adsorbed oxygen such as O2-, O- and O-2(-) are formed on grain surfaces. It is proposed that these behaviors contribute greatly to the generation of multiple types of grain boundary acceptor states in the ceramic.

关键词： XPS Analysis of Ni and Oxygen in Single-Sintered SrTiO3 Multifunction Ceramic Ni

Research on Ultrafine Tungsten Carbide-Cobalt(WC-Co) Cemented Carbide Rods of Miniature Drills for Highly Integrated Printed Circuit Board(PCB)

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Journal of materials Science & technology 2005年第3期21卷 353-356页

作者： Xiaoliang SHI, Gangqin SHAO, Xinglong DUAN and runzhang yuan state key laboratory of advanced technology for materials synthesis & processing, wuhan university of technology, wuhan 430070, China Lab. of advanced technology for materials synthesis and processing Wuhan University of Technology Wuhan 430070 China

Nanocrystalline tungsten carbide-cobalt (WC-Co) composite powders produced through spray thermal decomposition-continuous reduction and carburization technology were used to prepare φ3.25 mm×38 mm ultrafine tungsten carbide-cobalt (WC-Co) cemented carbide rods through vacuum sintering plus sinterhip technology. The microstructure, Vickers hardness, density and Rockwell A hardness (HRA), transverse rupture strength (TRS), saturated magnetization and coercivity force were tested. The results show that the average grain size of the sintering body prepared through vacuum sintering plus sinterhip technology was 430 nm; transverse rupture strength (TRS) was 3850 MPa; Vickers hardness was 1890 and Rockwell A hardness of sintering body was 93. High strength and high hardness ultrafine WC-Co cemented carbide rods used to manufacture printed circuit board (PCB) drills were obtained.

关键词： Nanocrystalline Composite powder Cemented carbide Rods

Nafion/Silicon Oxide Composite Membrane for High Temperature Proton Exchange Membrane Fuel Cell

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Journal of wuhan university of technology(materials Science) 2007年第3期22卷 478-481页

作者：余军 state key laboratory of advanced technology for materials synthesis and processing Wuhan University of Technology

Nafion/Silicon oxide composite membranes were produced via in situ sol-gel reaction of tetraethylorthosilicate （TEOS） in Nafion membranes. The physicochemical properties of the membranes were studied by FT-IR,TG-DSC and tensile strength. The results show that the silicon oxide is compatible with the Nation membrane and the thermo stability of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. Furthermore, the tensile strength of Nation/Silicon oxide composite membrane is similar to that of the Nation membrane. The proton conductivity of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. When the Nation/Silicon oxide composite membrane was employed as an electrolyte in H2/O2 PEMFC, a higher current density value （1 000 mA/cm^2 at 0.38 V） than that of the Nafion1135 membrane （100 mA/cm^2 at 0.04 V） was obtained at 110 ℃.

关键词： PEMFC composite membrane silicon oxide high temperature

Fabrication of A1/Al_2O_3 Composites and FGM

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Journal of materials Science & technology 2001年第6期17卷 646-648页

作者： Hong TAO, Chengji DENG, Lianmeng ZHANG and runzhang yuan state key laboratory of advanced technology for materials synthesis and processing, wuhan university of technology, wuhan 430070, China [Manuscript received November 27 wuhan Univ. of technol. Wuhan 430070 China

Al/Al203 composites of different ratios were hot-press sintered at 575~640℃ under a pressure of 30 MPa for 2 h in a vacuum furnace. It was found that the relative density of the Al/Al203 composites could be increased evidently with the rise of sinter temperature. No reaction occurred between At and Al203 at the sinter temperatures. Under 640℃-30 MPa-2 h experimental condition, Al/Al203 system FGM was successfully fabricated, and its density range changed quasi-continuously from 2.887×103 kg/m3 to 3.1909×103 kg/m3 within the middle 1.0 mm thickness range.

关键词： Fabrication of Al/Al2O3 Composites and FGM Co Al

Novel Magnetorheological Suspensions Based on Co-Phthalocyanine/Fe Nanocomposite Particles

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Journal of materials Science & technology 2001年第5期17卷 511-516页

作者： Rongzhou GONG and Zekun FENG Dept. of Electronic Science and technology, Huazhong university of Science and technology, wuhan 430074, China Jianguo GUAN and runzhang yuan state key laboratory of advanced technology for materials synthesis and processing, wuhan Univ. of technol. Wuhan 430070 China

A novel magnetorheological (MR) suspension was based on methyl silicone oil and cobalt-phthalocyanine (Co-Pc)/Fe nanocomposite particles, which were synthesized by thermally decomposing liquid carbonyl Fe in the solution of Co-Pc in N, N-dimethyl formamide. The nanocomposite particles were fully characterized by XRD, SEM and HREM, and the thermal, magnetic and MR properties of nanocomposite particles were measured. Such factors as weight percent of particles (w), magnetic field strength (H), temperature (T) and shear rate (gamma) etc influencing on MR properties were investigated. The results indicated that Co-Pc/Fe nanocomposite with density of 3.66 g/cm(3) was almost micro-sized regular spheroids consisting of tens of Co-Pc coated alpha -Fe nanoparticles in inner and Co-Pc layers on surface of the spheroids. They showed good characteristics of anti-oxidation and soft magnetic. Increment of w increased field-induced shear stress (Delta tau) and zero-field viscosity (eta (0)) of MR suspensions monotonously, and improved anti-settlement stability, but eta (0) increased more markedly than Delta tau with increasing w. Delta tau was basically independent on T and gamma while increased obviously with increasing H. With increasing T, response time of the MR suspension to external magnetic field seemed to decrease. As a result, MR suspensions with satisfactory stability and rapid, completely reversible and significant MR effect can be obtained from Co-Pc/Fe nanocomposite particles.

关键词： Fe Co Novel Magnetorheological Suspensions Based on Co-Phthalocyanine/Fe Nanocomposite Particles

Effect of Grinding and Polishing on the Residual Stress and Bending Strength of a Silicon Nitride Ceramic

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Journal of wuhan university of technology(materials Science) 2005年第1期20卷 46-48页

作者：高玲 state key Lab of advanced technology for materials synthesis and processing Wuhan University of TechnologyWuhan 430070China

The residual stresses on the surface of the d ifferently ground and polished silicon nitride ceramics were measured using X-r ay diffraction and identified by *** effect of the residual stress on the be nding strength was *** investigations show that the grinding proces s can introduce subatantial tensile residual stresses up to 290MPa on the surfac e of silicon nitride ceramics,which has a significant effect on reducing the ben ding strength of the ceramics after ***,in comparison with the ceramic s with a rough surface,the ceramics with a mirror image surface may have a lower *** can smooth the residual *** we evaluate the qualit y of the ceramic components after grinding,we must take residual stress into con sideration. The grinding methods and grinding conditions must be carefully selec ted in order to get the favorite residual stress as well as the surface smoothne ss.

关键词： residual stress grinding bending strengt h ceramics

Phenomenon of “contact guidance” on the surface with nano-micro-groove-like pattern and cell physiological effects

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Chinese Science Bulletin 2009年第18期54卷 3200-3205页

作者： ZHOU Feng 1,2, yuan Lin 1,3, HUANG He 1,2 & CHEN Hong1,2 1 state key laboratory of advanced technology for materials synthesis and processing, wuhan 430070, China 2 School of materials Science and Engineering, wuhan university of technology, wuhan 430070, China 3 Biomedical materials Research Center, wuhan university of technology, wuhan 430070, China state key laboratory of advanced technology for materials synthesis and processing Wuhan China School of materials Science and Engineering Wuhan University of Technology Wuhan China Biomedical materials Research Center Wuhan University of Technology Wuhan China

The topography of material surface has important influence on cell behavior and physiological functions. Groove-like pattern has drawn much attention among various patterns, due to the phenomenon of "contact guidance" induced by this kind of topography. This review mainly focuses on "contact guidance" formation as well as its influence on cell behavior and physiological effects. The possible mechanisms of "contact guidance" formation were discussed. The research trend and the potential applications were also suggested.

关键词：细胞行为生理功能材料表面逻辑效应触指纳米微米生理效应

Fractal Analysis of Gas Diffusion Layer in PEM Fuel Cells

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Journal of wuhan university of technology(materials Science) 2006年第1期21卷 22-25页

作者：石英肖金生 state key laboratory 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 laboratory 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

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超声化学法制备CoSb_3纳米粉体

武汉理工大学学报 2009年第16期31卷 5-7页

作者：徐源鄢永高唐新峰武汉理工大学材料复合新技术国家重点实验室武汉430070

Skutterudite化合物具有较高的热导率和Seebeck系数,但具有较高的热导率从而导致热电性能偏低。通过超声化学法合成CoSb3化合物纳米粉体具有很高的应用前景。以CoCl2、SbCl3为原料,采用乙醇为溶剂、NaBH4为还原剂,在超声条件下通过液相... 详细信息

Skutterudite化合物具有较高的热导率和Seebeck系数,但具有较高的热导率从而导致热电性能偏低。通过超声化学法合成CoSb3化合物纳米粉体具有很高的应用前景。以CoCl2、SbCl3为原料,采用乙醇为溶剂、NaBH4为还原剂,在超声条件下通过液相反应制备颗粒尺寸为10 nm的非晶态Co、Sb粉体。在H2气氛下380℃反应5 min得到粒径30—50 nm的CoSb3化合物纳米粉体。

关键词：超声化学法纳米cosu3 热处理