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Study on the diamond/ultrafine WC-Co cermets interface formed in a SPS consolidated composite

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Rare Metals 2006年第2期25卷 150-155页

作者： SHI Xiaoliang SHAO Gangqin DUAN Xinglong yuan runzhang State Key Laboratory of Advanced Technology for Materials Synthesis ＆ Processing Wuhan University of Technology Wuhan 430070 China

Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering （SPS） process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDXS）. The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix.

关键词： diamond nanocrystalline WC-Co composite powders interface spark plasma sintering

Densification of W-Ni-Cu and W-Fe-Cu Alloys at 1573 K

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Journal of Materials Science & Technology 1999年第1期15卷 94-96页

作者： Xiong, Huaping Zhang, Lianmeng Shen, Qiang yuan, runzhang Wuhan Univ Technol State Key Lab Mat Synth & Proc Wuhan 430070 Peoples R China

The tungsten alloys with Ni-Cu and Fe-Cu additives were sintered at 1573 K for 1 h by hot-pressing method. It was found that the alloy relative density can be improved with the addition of Cu when Cu content is not very high, and W95Ni3Cu2 alloy with full density can be obtained Under the sintering condition. However, with the Cu content further increasing, the relative density change of W-Ni-Cu alloy and W-Fe-Cu alloy shows different trends, the former tends to decrease obviously, but the latter shows little change. According to the analysis results, the element Cu has different effects on the activation capability of Ni and Fe during sintering of the tungsten alloys. (Edited author abstract) 7 Refs.

关键词： Tungsten alloys

CHARACTERIZATION OF MANGANESE PHTHALOCYANINE-Fe_3O_4 NANOPARTICLE COMPOSITE AND ITS ELECTROMAGNETORHEOLOGICAL FLUID

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Journal of Wuhan University of Technology(Materials Science) 1999年第1期14卷 35-40页

作者： HUANG Jun GUAN Jianguo ZHAO Suling yuan runzhang Wuhan University of Technology Wuhan University of Technology China Fiber Optic Sensing Technol. Centre Wuhan Univ. of Tech. Wuhan 430070 China

Manganese phthalocyanine (MnPc)-Fe3O4 nanoparticles composite was prepared and characterized. The results show that MnPc are completed on the surface of Fe3O4 nanoparticles in the state of single molecule. There is effective composite between MnPc and Fe3O4 nanoparticles which can improve the antioxidization ability of Fe3O4 nanoparticles greatly. The composite was dispersed into chlorinated paraffin oil to form electromag-netorheological (EMR) fluid with high activity, and the EMR properties of this EMR fluid are studied.

关键词： manganese phthaloc yanine nanopar- ticles composite electramagnetorheological fluid

Fabrication of Mo Ti functionally graded material

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中国有色金属学会会刊：英文版 1999年第3期9卷 582-585页

作者： Xiong Huaping(熊华平) Zhang Lianmeng(张联盟) Shen Qiang(沈强) yuan runzhang(袁润章) Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China

Molybdenum alloys and titanium alloys were sintered at 1 473K for 1 h under a pressure of 30 MPa. It was found that the addition of Al can increase evidently the relative density of sintered Mo Fe alloys. The Fe Al additives are also suitable for the sintering of titanium alloys, and the Mo alloy and Ti alloy can be densified concurrently with the same additives 3%Fe 1.5%Al. The experimental results also showed that during the sintering of Mo Ti alloys the Fe Al sintering aids promoted the formation of Mo Ti solid solution, but the solid solution reaction occurred at the low sintering temperature of 1 473 K is inadequate. Finally, Mo Ti system functionally graded material has been successfully fabricated. Its density changed gradually from 9.52 g/cm 3 to 4.48 g/cm 3 in thickness direction. Such a material can be used in dynamic high pressure technology.

关键词： molybdenum titanium functional gradient alloys sintering

SYNTHESIS AND CRYSTAL STRUCTURE OF A NEW COMPOUND Sr_6Sn_2Nb_8O_30

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Journal of Wuhan University of Technology(Materials Science) 1999年第2期14卷 35-39页

作者： FANG Liang ZHANG Hui WU Bolin yuan runzhang Wuhan University of Technology Wuhan University of Technology China State Key Lab. Adv. Tech. Mater. S. Wuhan Univ. of Tech. Wuhan 430070 China

A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined by X-ray diffraction, and its belongs to tungsten bronze structure. Sr6Sn2Nb8O30 crystallizes in orthorhombic system with unit cell parameters a= 17. 579 (DA,6= 17. 509(DA,c=7. 7880(5)A,Z = 4 and space group Cmm2.

关键词： Sr_6Sn_2Nb_8O_30 system new compound tungsten bronze structure

STUDY OF COMPOSITE BY MELTING INTERCALATION OF POLYACRYLAMIDE IN MONTMORILLONITE

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Journal of Wuhan University of Technology(Materials Science) 1998年第2期13卷 32-36页

作者：陈文 Wuhan University of Technology China Coll. of Mat. Sci. and Engineering Wuhan Univ. of Tech. Wuhan 430070 China

The synthesis of polyacrylamide (PAM)-montmorillinote composite by direct melting intercalation of polymer powders is studied using XRD, IR and DSC. The results show that melt PAM can intercalate into montmorillonite layer. The layered distance(d//0//0//1) of montmorillonite increases, and the melt absorption peak of PAM in layer has eliminated. (Author abstract) 8 Refs.

关键词： PAM melt intercalation montmorillonite intercalation composite

RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD FOR EFFECTIVE NONLINEAR PROPERTIES OF COMPOSITE MATERIALS

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Journal of Wuhan University of Technology(Materials Science) 2000年第2期15卷 1-6页

作者：瞿鹏程 Wuhan University of Technology China State Key Lab. Mat. Synthesis Proc. Wuhan University of Technology Wuhan 430070 China

Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of linear problems are difficult to be managed by the theoretical methods. The present study aims to use the developed method, the random microstructure finite element method, to deal with these nonlinear problems. In this paper, the random microstructure finite element method is used to deal with all three kinds of nonlinear property problems of composite materials. The analyzed results suggest the influences of the nonlinear phenomena on the effective properties of composite materials are significant and the random microstructure finite element method is an effective tool to investigate the nonlinear problems.

关键词： random microstructure finite element method effective property composite materials nonlinear property problems

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

RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD AND ITS VERIFICATION FOR EFFECTIVE PROPERTIES OF COMPOSITE MATERIALS

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Journal of Wuhan University of Technology(Materials Science) 2000年第1期15卷 6-12页

作者：翟鹏程 Wuhan University of Technology China State Key Lab. Mat. Synthesis Proc. Wuhan University of Technology Wuhan 430070 China

The present study aims at developing a new method-RandomMicrostructure Finite Element Method (RMFEM) for the effectiveproperties of com- Posite materials. In this method, a randommicrostructure Model is used to simulate the microstructure of thereal composite materials. The physical fields in such a randomMicrosturucture model under specified boundary and initial Conditionsare analyzed by finite element method.

关键词： random microstructure finite elment method effective property compositematerials