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Crystallization Behaviour of Laser Synthesized Nanometric Amorphous Si_3N_4 Powders

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Journal of Materials Science & Technology 1995年第3期11卷 187-191页

作者： Yali LI Yong LIANG Zhuangqi HU(National key Lab. of rapidly {2. nonequilibrium alloys, institute of metal research,chinese academy of sciences, shenyang, 110015,{12.) Inst of metal research Chinese Acad of Sciences Shenyang China

The crystallization behaviour of the laser synthesized nanometric amorphous Si3N4 powders with the particle size of 15 nm in diameter has been studied between 12.0° and 1700℃ by XRD,TEM and FTIR techniques. A small amount of β-Si3N4 formed at 12.0℃ and increased slowly until the α- β transformation happened at 1700℃, whereas α-Si3N4 appeared at 1300℃ andincreased rapidly between 1500-1600℃. The formation of β phase at the lower temperature was caused by the nitridation of free Si due to the preexisted β-nuclei in the Si3N4 particles, whereasthe α phase was formed by solid crystallization from the amorphous matrix. There were α and β SiC formed at 1700℃ due to the presence of Sio and Co gases in the system. FTIR analysis shows that two new IR absorption at 1356 and 142. cm-1, and an overall strong absorption in wide wavenumber range resulted from the powders annealed at 1600 and 1700℃ respectively

关键词： Si Am Crystallization Behaviour of Laser Synthesized Nanometric Amorphous Si3N4 Powders OO

EFFECT OF PRE-ANNEALING ON CRYSTALLIZATION KINETICS OF AMORPHOUS Ni-P alloys

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Acta metallurgica Sinica(English Letters) 1991年第8期4卷 88-92页

作者： LUKe WANG Jingtang laboratory of rapidly {2. non-equilibrium alloys,institute of metal research,Academia Sinica,shenyang,china Acad Sinica Shenyang China

The effect of pre-annealing treatment on the crystallization kinetics parameters of amorphous Ni-P alloys has been *** results showed that the crystallization tem- perature,T_p and T_x,the apparent activation energy,E_c,as well as the Avrami exponent for isothermal crystallization,n,decrease significantly,while ΔT_(px)=T_p-T_x increases with the elongation of pre-annealing time at 570 K.

关键词： amorphous alloy crystallization kinetics crystallization temperature activation energy for crystallization

Trend and Development of Semi-Solid metal Processing

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Journal of Materials Science & Technology 2000年第5期16卷 453-460页

作者： Xianfeng PAN, Haifeng ZHANG, Aimin WANG, Bingzhe DING, Keqiang QIU and Zhuangqi HU (State key laboratory of {2. solidified nonequilibrium alloys, institute of metal research, chinese academy of sciences, shenyang 110015, china) State key laboratory of {2. solidified nonequilibrium alloys Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on the basic rheological theory are presented for more applications. Further consideration of the development and application of SSM technique is also proposed.

关键词： SSM Trend and Development of Semi-Solid metal Processing

Preparation of Ultrafine Si Powders from SiH_4 by Laser-induced Gas Phase Reaction

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Journal of Materials Science & Technology 1995年第1期11卷 71-74页

作者： Yali LI Yong LIANG Kesheng XIAO Fen ZHENG and Zhuangqi HU(State key laboratory of {2. solidified nonequlibrium alloys, institute of metal research,chinese academy of sciences, shenyang, 110015,{12.)

High quality ultrafine Si powders have been synthesized from SiH4 by laser induced gas phase reaction. The powders prduced under different synthesis conditions have mean particle size of 10-12.nm in diam. with narrow particle size distribution, and free of hard *** powders are polycrystalline with the ratio of mean grain to particle diameter being between 0.3-0.7. The size of the powder increases with increasing laser power and reaction pressure,but decreases with increasing silane gas flow rate and the addition of Ar diluent. Grain sizes drop distinctly with the rise of the addition of Ar gas and laser power, but change little with the gas flow rate and reaction temperature. The formation of Si particles under different synthesis conditions is discussed

关键词： Si Preparation of Ultrafine Si Powders from SiH4 by Laser-induced Gas Phase Reaction Figure

metals Supported Water Monomers:the Bonding Nature Revisited

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Journal of Materials Science & Technology 2010年第2期26卷 97-105页

作者： Jibiao Li, Shenglong Zhu and Fuhui Wang State key laboratory for Corrosion and Protection,{2., chinese academy of sciences, shenyang 110015, china [a] State key laboratory for Corrosion and Protection institute of metal {2. chinese academy of {2. shenyang 110015 china

A single water monomer is known as a hard-to-observe molecule even in the presence of metal surfaces as supporting matrix. This review highlights effort in experimental characterizations and theoretical modeling of transition metals supported water monomers with attention given to its structure and bonding, together with the insights that we have provided into the bonding nature of the water-interactions by the newly employed projected PDOS （partial density of states） difference analysis, which is proved to be an effective tool to be elucidate such bonding nature. The general s-d hybridization and d-shell effect are summarized, and how these effects can be tuned by tailoring local surface configurations is discussed.

关键词： Water monomer Adsorption Surface bonding Transition metals

Rheological behaviour of semi-solid succinonitrile-camphor alloy

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Journal of University of Science and Technology Beijing 2003年第1期10卷 25-29页

作者： Zhenyao WangState key laboratory for Corrosion and Protection,{2., chinese academy of sciences, shenyang 110016, china Lab. for Corrosion and Protection Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Rheology experiments were carried out on succinonitrile-4% (mass fraction) camphor alloy, using a Haake VT550 viscometer. The results showed that the steady state viscosity of succinonitrile-4% camphor alloy in semi-solid process can be described well by the classical power law of viscosity versus shear rate, η= kγm, and the test method can be used to simulate the semi-solid processing for {2.s. The viscosity of the organic alloy decreases with increasing shear rate at a given temperature within liquid-solid range, and the viscosity of the organic alloy slurries increases with decreasing temperature, decreases with decreasing cooling rate. The structure and viscosity of organic alloy during solidification are strongly influenced by shear rate.

关键词： rheology semi-solid processing viscosity organic alloy microstructure

Oxidation Behaviour of Sputtered Ni-3Cr-2.Al Alloy

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Journal of Materials Science & Technology 2000年第1期16卷 88-90页

作者： Guofeng CHEN and Hanyi LOU (State key laboratory for Corrosion and Protection,{2., chinese academy of sciences, shenyang 110015, china) State key laboratory for Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The oxidation behavior of sputtered Ni-3Cr-2.Al coating at 900℃ in air was investigated. A dense Al2.3 layer was formed on the sputtered Ni-3Cr-2.AI coating after 2.0 h oxidation. However, owing to the segregation of Ni3Al during oxidation process at high temperature, the spinel NiAI2.4 was also formed in the Al2.3 layer. It was found that the formation of NiAI2.4 had no detrimental effect on the oxidation resistance of the sputtered N?3O-2.AI coating due to the excellent adhesion shown by the Al2.3 and NiAl2.4complex oxide scale.

关键词： Al Oxidation Behaviour of Sputtered Ni-3Cr-2.Al Alloy Cr Ni

Thermodynamic Calculation of Si_3N_4-SiC Phase equilibrium

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Journal of Materials Science & Technology 1995年第6期11卷 466-468页

作者： Yali LI and Zhuangqi HU (National key Lab. of rapidly {2. nonequilibrium alloys, institute of metal research,CAS, shenyang, 110015, china)Yang GAO and Yong LIANG (Laser Processing Dept., institute of metal research, CAS, shenyang, 110015, china) Inst of metal research Chinese Acad of Sciences Shenyang China

SisN4 and SiC phase stability via gas phase reactions among SiO, CO/CO2.and N2.has been calculated based on thermochemical equilibrium. The influences of carbon activity (αC), and the partial pressure of SiO (PSiO), CO (PCO) and N2.(PN2. on the Si3N4-SiC stability have been studied and the related phase diagrams have been constructed. Result shows that the lowering αC and PCO/PSiO ratio and the increasing PN2.greatly elevate the Si3N4-SiC equilibrium temperature. Some previously observed experimental results related to Si3N4 and SiC formation at different temperature from the gas phase reactions have been discussed and some guides for sintering and synthesis Of the Si3N4 materials have been proposed

关键词： SiC Thermodynamic Calculation of Si3N4-SiC Phase equilibrium SiO

Oxidation and Hot Corrosion Behavior of a Composite Coating System

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Journal of Materials Science & Technology 2003年第6期19卷 567-570页

作者： Dongbai XIE and Fuhui WANGState key laboratory for Corrosion and Protection,{2., chinese academy of sciences, shenyang 110016, china Lab. for Corrosion and Protection Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

The oxidation and hot corrosion behavior of Co-Ni-Cr-AI-Ta-Y coating produced by magnetron sputtering with and without enamel coating has been investigated in air at 900℃ and in molten 75 wt pct NaCl+2. wt pct Na2.O4 at 850℃. The results show that the enamel coating possesses good hot corrosion resistance in the molten salts, in comparison with the sputtered Co-Ni-Cr-AI-Ta-Y coating. In the hot corrosion test, breakaway corrosion did not occur on the samples with enamel coating and the composition of enamel coating did not significantly change either. The oxidation resistance of the sputtered coating, which offers good adhesion, can be improved by the enamel coating.

关键词： Enamel coating Sputtered coating Hot corrosion Isothermal oxidation