REN Jun Baotou Research Institute of Rare Earth Metals
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Ministry of Metallurgical Industry
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Baotou
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China engineer
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Baotou Research Institute of Rare Earth Metals
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Baotou 014010
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China
金属学报(英文版)
The flotation behaviour and mechanism of bastnaesite with N-hydroxyl phthalicimide were investigated by ξ-potential measurement,infrared spectrum and quantum chemistry calculation.The results show that 3 oxygen atoms from N-hydroxyl phthalicirnide chelate the rare earth ions on the surface of bastnaesite to form double five-chain O=C-N-O- RE(Ⅲ)-O chelate which is chemically adsorbed on the surface of bastnasite,thus making N-hydroxyl phthalicimide an effective collector for bastnaesite.
关键词:
N-hydroxyl phthalicimide
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null
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null
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Materials Science and Technology
The effect of rare earth metals (REMs) on the microstructure and segregation during solidification in a highly alloyed Ni based superalloy was investigated. Rare earth metals considerably decrease the amounts of coarse columnar grains and increase the amounts of equiaxed grains. They are segregated to the interdendritic regions mainly as the precipitate of Ni5Ce. Both the dimension and distribution of gamma' particles and MC carbide are modified by REM. Eutectic (gamma+gamma'), Laves phase, delta phase and sigma phase are precipitated in the interdendritic regions because of the serious segregation of niobium and titanium aggravated by REM. The differential thermal analysis indicates that the precipitation temperature of phases and the solidification sequence of the superalloy can be changed due to the additions of REM.
关键词:
Rare earth metals;Segregation;Solidification;Nickel based superalloy;microstructure;segregation;steel;alloy
WANG Xiaotian YAO Yinliang SHAO Tanhua Xi′an Jiaotong University
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Xi′an
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China
金属学报(英文版)
The microstruetural transformation of steels:20SiMn2V,20SiMn2VRE,40SiMn2V and 40SiMn2VRE during quenching and tempering have been examined by TEM,X-ray diffraction and dilatometer.It was shown that the addition of rare earth metals not only can refine the austenite grains of the low or medium carbon steels and packet of lath martensite and lath size,lower the M_s temperature,but can also raise the relative percentage of disloca- tion substructure of martensite in medium carbon steel,but there is little effect on volume frac- tion and thermal stability of retained austenite quenching and tempering structure of low or medium carbon steels.The rare earth metals may remarkably inhibit the decomposition of low carbon martensite during low temperature tempering,retard the precipitation of cementite plates in lath grains and delay the spheroidization of carbides.They may also restrain obvious- ly the precipitation and spheroidization of cementite in medium carbon martensite during high temperature tempering.
关键词:
rare earth metals
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null
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null
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Zeitschrift Fur Physik B-Condensed Matter
Both parabola and ellipse separating schemes are used to study the solid solubilities for the binary alloy systems based on the 13 rare earth metals. It has been found that the soluble elements can be separated from the insoluble ones by a parabola y(1) = a - bx(1)(2) or an ellipse (x(2)-m)(2)/c(2) + (y(2)-n)(2)/d(2) = 1. The results show that the overall reliabilities of the solid solubilities for the 897 binary alloys based on the rare earth metals are 89.2% and 92.8% for the parabola and ellipse regularities respectively. The constants a and b in the parabola equation, and m, n, c and d in the ellipse equation are discussed, which can be related to some appropriate parameters for each host metal respectively.
关键词:
Journal of Physics D-Applied Physics
A comprehensive review is given of recent advances in the study of metastable phases in rare-earth permanent magnets. The relations between the structures of the metastable and equilibrium phases and the transformations from the former to the latter are discussed. The formation of the phases is found to depend on the difference between the symmetries of the metastable and equilibrium phases. The magnetic properties of the metastable-phase rare-earth permanent magnets synthesized by various processes, such as mechanical alloying, mechanical milling, rapid quenching, hydrogenation, disproportionation, desorption and recombination, solid-state reaction, solid-gas reaction, self-flux and sputtering, are compared. The main conclusion of this article is that searching for new metastable phases with high magnetic performance will be one of the most active directions in the research on rare-earth permanent magnets.
关键词:
fe-c alloys;disproportionation-desorption-recombination;solidified;sm-fe;r = nd;high-coercivity;magnetocrystalline anisotropy;intermetallic compounds;remanence enhancement;crystal-structure;high-performance
X.K. Tao
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X.Cong
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R.S. Peng
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J.Liu and Z.Y. Liu Tianjin Institute of Technology
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Tianjin 300191
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China
金属学报(英文版)
This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.
关键词:
rare earth elements
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null
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C.M. Yang
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Q.R. Zhang and Z. Fang(Department of Chemistry
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Central South University of TecHnology
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Changsha 410083
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China)
金属学报(英文版)
Polyaniline doped with rare earth chloride was synthcsized in organic solvent and identified by clemental analysis and ithered spectroscopy. The experimental results show that there exist both doping and complexation at the same time in the resulting product. When pH<4, prototnic acid doping is predominating, whereas rare earth ion complexation is predominating when pH>1. Moreover, polyanitine doped wih rare earth chloride exhibits better thermal stability than that doped with hydrochloric acid.
关键词:
dope
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null
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