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Valence Distribution in AT_xV_(6-X)O_(11) Compounds

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Journal of Materials Science & Technology 1999年第6期15卷 551-554页

作者： Hongchao LIU and Changlin KUO(shanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china) chinese Acad Sci Shanghai Inst Ceram Shanghai 200050 Peoples R China

The distribution of trivalent and tetravalent cations in several ATxV6-xO11 compounds was quantitatively studied by the bond valence method. In SrV6O11, the M(3) sites were mainly occupied by trivaient cations; while M(1) and M(2) sites were shared by trivalent and tetravalent cations, the relative content of tetravalent at M(1) sites was higher than at M(2) sites. During substitution process, the trivalent cations preferred to occupy M(3) sites, tetravalent ones preferred to occupy M(2) sites. The occupancy of trivalent and tetravalent cations at M sites would change with the substitution

关键词： AT X)O Valence Distribution in AT_xV Compounds

X-ray Powder Diffraction Pattern of Bi_4(SiO_4)_3

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Journal of Materials Science & Technology 1997年第2期13卷 145-148页

作者： Hongchao LIU Changlin KUO (shanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china) shanghai institute of ceramics Chinese Academy of Sciences Shanghai 200050 China

In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figure-of-merits, which qualify agreement between observed and calculated relative intensities. F30 is 158.90 (0.0059, 32), intensity figure of merit Rint is 8.7, I20(17), 8.0. The values of figure-of-merits show that the data of JCPDS cards are distorted. Both the experimental and calculated peak positions and heights are listed in detail.

关键词： SiO4 X-ray Powder Diffraction Pattern of Bi4 Bi

Formation and Oxidation Resistance of Silicide Coatings for Mo and Mo-Based Alloys

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Journal of Materials Science & Technology 2001年第4期17卷 479-481页

作者： Yu WANG , Yunpeng LI and Xingfang HU shanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china chinese Acad Sci Shanghai Inst Ceram Shanghai 200050 Peoples R China

The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gas- phase deposition method. has been studied by examining the microstructure of coatings and the relationship between coating thickness and process parameters. It was shown that the growth of coatings was diffusion-controlled, the diffusion of silicon to be coated into Mo or Mo-base alloys was mainly responsible for the formation of silicide. The relationship between initial silicide thickness and oxidation resistance was also investigated, and the equation of service life of the coatings at high temperature in air is presented.

关键词： Mo Formation and Oxidation Resistance of Silicide Coatings for Mo and Mo-Based Alloys

Kinetic Process and Conductivity of Ag^+ Ion Exchange for Polycrystalline Na-β"-Al_2O_3

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Journal of Materials Science & Technology 1996年第4期12卷 315-317页

作者： Jianhua YANG(shanghai institute of ceramics, chinese academy of Scieoces, shanghai 2.0050, china) shanghai institute of ceramics Chinese Academy of Sciences Shanghai 200050 China

This paper reports the kinetic process of Ag ion exchange for the polycrystalline Na-β'-*** interdiffusion coefficients in the process of Ag+ and Na+ ion exchange have been calculated with an 'one dimensional double side diffusion model'. Microstructures of the samples were observed and analysed by XRD, EMPA, SEM. The results of the conductivity measurements for samples with Na+, Ag+ and Na+-Ag+ mobile ions are presented and explained

关键词： Kinetic Process and Conductivity of Ag Ion Exchange for Polycrystalline Na Al2O3

Removal Behaviors of Different SiC ceramics during Polishing

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Journal of Materials Science & Technology 2010年第2期26卷 125-130页

作者： Guiling Liu, Zhengren Huang , Xuejian Liu and Dongliang Jiang Structural ceramics Center, shanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china [a] Structural ceramics Center shanghai institute of ceramics chinese academy of sciences shanghai 2.0050 china

Comparative experiments were conducted to reveal the removal behaviors of three kinds of silicon carbide （SIC） ceramics during polishing and the effects of ceramic microstructure on the surface quality were also reported. Experimental results show that the second phase in SiC ceramics plays an important role in the surface quality when its size is large enough. The surface quality is enslaved to the formation of steps at interfaces between second phase and SiC matrix that results from different elastic modulus and hardness between two phases. Under 3 μm abrasive grains polishing condition, different SiC ceramics show different removal mechanisms. With decreasing abrasive grain size, all of different SiC ceramics exhibit a ductile removal mode, which decreases surface roughness efficiently.

关键词： SiC Surface quality Removal behavior Polishing

Densification and Microstructure of β-sialon/Nano-size SiC Composites

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Journal of Materials Science & Technology 1997年第4期13卷 339-341页

作者： Cheng ZHANG Danyu JIANG Qiang LI and Weiying SUN (shanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china) shanghai institute of ceramics Chinese Academy of Sciences Shanghai 200050 China

β-sialon/nano-size SiC composite ceramic with DyAG(Dy3Al5O12) as grain boundary phase was fabricated through hot-pressing. The effect of nano-size SiC on densification, phase composition, microstructure and mechanica... 详细信息

关键词： Nano SiC Densification and Microstructure of sialon/Nano-size SiC Composites

Tape Casting of Al_2O_3-TiB_2/Al_2O_3-Nano-TiC Multilayer Composites

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Journal of Materials Science & Technology 1997年第4期13卷 324-326页

作者： Yuping ZENG Dongliang JIANG Shouhong TAN and Jingkun GUO(shanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china) shanghai institute of ceramics Chinese Academy of Sciences Shanghai 200050 China

Ceramic tapes, containing Al2O3-25 wt pct TiB2(B) and Al2O3-25 wt pct nano-TiC (c), have been obtained by tape casting process. Numerous tapes (about 60～80 tapes) were prepared by stacking in turn the composition (B) and (C), laminating under 10 MPa pressure, eliminating the solvent and burning out the polymer additives. The final green bodies were hot pressed at 1750℃ and 30 MPa. The composite has a bending strength of 568 MPa and a fracture toughness of 5.8 M Pa·m1/2. SEM analysis exhibits that Al2O3 particle growth was inhibited by TiC particles in C. but TiB2 particles could not hinder Al2O3 growth in B. The curves of GTA indicates that all organic additives could be removed completely above 600℃

关键词： Nano TiB Al Tape Casting of Al2O3-TiB2/Al2O3-Nano-TiC Multilayer Composites TiC

Microstructure and Properties of Plasma Spraying Boron Carbide Coating

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Journal of Materials Science & Technology 2000年第1期16卷 63-66页

作者： Yi ZENG, Jingwei FENG and Chuanxian DING (shanghai institute of ceramics, chinese academy of sciences, 1295 Dingxi Road, shanghai 2.0050, china) shanghai institute of ceramics Chinese Academy of Sciences 1295 Dingxi Road Shanghai 200050 China

Microstructure of plasma spray boron carbide coating was studied by SEM and TEM. Its physical, mechanical and electrical properties were measured. The results showed that high microhardness, modulus and low porosity of B4C coating were manufactured by plasma spray. It was lamellar packing and dense. The B4C coating examined here contained two principal structures and two impurity phase besides major phase. The relatively small value of Young's modulus, comparing with that of the bulk materials, is explained by porosity . The Fe impurity phase could account for the relatively high electrical conductivity of boron carbide coating by comparing with the general boron carbide materials.

关键词： Microstructure and Properties of Plasma Spraying Boron Carbide Coating

Synthesis and crystal structure of SrNi_xV_(6-x)O_(11)

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chinese Science Bulletin 1997年第10期42卷 850-855页

作者： LIU Hongchao, GUO Changlin and TU Hengyongshanghai institute of ceramics, chinese academy of sciences, shanghai 2.0050, china shanghai institute of ceramics Chinese Academy of Sciences Shanghai China

THE AV6O11（A,alkaline or alkaline earth metals）-type compounds are the only phases

关键词： SrNixV6-xO11 crystal structure X-ray powder diffraction Rietveld method bond-valence method.