Sample records for rare-earth iron alloys

  1. A Rare Earth High-iron Aluminum Alloy Cable Company to Settle in Chongqing


    <正>On September 14,the reporter learnt from the Seminar on Application of New Rare Earth High-iron Aluminum Alloy Cable Technologies for Energy Conservation and Environmental Protection held by Chongqing Electric Industry Association that a rare earth high-iron aluminum alloy cable company with

  2. Effect of Rare Earth Alloy Modification on High Carbon Equivalent Gray Cast Iron of Automotive Brake Drum

    ZHANG Daowen; LI Zhu; HUANG Jie


    Effect of rare earth alloy modification on properties and microstructure of high carbon equivalent gray cast iron was investigated.The experimental results show that in the way of mechanical property,when the addition of rare earth alloy is 0.2% and 0.3%,the tensile strength of cast iron increases.In the way of microstructure,the addition of rare earth alloy increases the number of primary austenite dendrites,reduces secondary dendritic arm spacing,and changes the eutectic size and quantity.When rare earth alloy is added into gray cast iron,the morphology and quantity of graphite play a major role on the improvement of tensile strength.

  3. Generation and characterization of anisotropic microstructures in rare earth-iron-boron alloys

    Oster, Nathaniel

    The automotive industry is currently being directed toward electrification of their fleets. In order to provide these hybrid or electric vehicles, lightweight high torque electric motors are needed. Permanent magnet (PM) brushless motors have been identified as the preferred motors for these applications. In order to effectively provide these motors, cost-effective high strength PMs are needed. The use of polymer bonded PMs is one method to reduce processing costs, but performance is decreased unless anisotropic PMs can be formed. New processing methods to form anisotropic mixed rare earth (MRE)-iron-boron PM particulate were studied in this work. Two primary processing routes were identified and investigated: controlled devitrification through application of uniaxial pressure and rapid directional solidification utilizing a segregating additive. In addition, further control of the melt-spinning process was achieved through control of wheel surface temperature and finish. Controlled devitrification was found to produce an anisotropic, nanocrystalline microstructure, as observed through TEM and XRD studies. A high defect density within the structure, unprecedented in RE2Fe14B microstructures, was observed. It is surmised that the defects cause soft magnetic behavior. Stabilization of a columnar, textured microstructure was achieved through the utilization of moderate wheel speeds during melt-spinning, in combination with minor additions of Ag to the alloy. The texture was seen to be altered from that typically seen in RE2Fe14B alloys melt-spun at low-to-moderate wheel speeds. It was observed that this occurs through a modification in the solidification pathway, catalyzed by the addition of Ag. In addition to the altered texture, the presence of fine precipitates within the matrix and varying interdendritic phases was observed. Alteration of wheel surface temperature and surface finish was seen to have significant effects on the ability to form amorphous material in

  4. Generation and Characterization of Anisotropic Microstructures in Rare Earth-Iron-Boron Alloys

    Oster, Nathaniel [Iowa State Univ., Ames, IA (United States)


    The goal of this work is to investigate methods in which anisotropy could be induced in fine-grained alloys. We have identified two general processing routes to creating a fine, textured microstructure: form an amorphous precursor and devitrify in a manner that induces texture or form the fine, textured microstructure upon cooling directly from the liquid state. Since it is possible to form significant amounts of amorphous material in RE-Fe-B alloys, texture could be induced through biasing the orientationof the crystallites upon crystallization of the amorphous material. One method of creating this bias is to form glassy material and apply uniaxial pressure during crystallization. Experiments on this are presented. All of the work presented here utilizes melt-spinning, either to create precursor material, or to achieve a desired final microstructure. To obtain greater control of the system to process these materials, a study was done on the effects of heating the wheel and modifying the wheel’s surface finish on glass formation and phase selection. The second general approach—creating the desired microstructure directly from the liquid—can be done through directional rapid solidification. In particular, alloys melt-spun at low tangential wheel speeds often display directional columnar growth through a portion of the ribbon. By refining and stabilizing the columnar growth, a highly textured fine microstructure is achieved. The effects of adding a segregating element (Ag) on the columnar growth are characterized and presented.

  5. Theory of Rare-Earth Alloys

    Lindgård, Per-Anker


    A mean-field random alloy theory combined with a simple calculation of the exchange interaction J(c,Q) is shown to quantitatively account for the phase diagrams for alloys of rare-earth metals with Y, Lu, Sc, and other rare-earth metals. A concentration-dependent J(c,Q) explains the empirical 2...... to account for all alloys except the Sc based. The exceptional behavior of the Sc alloys is due to a low density of states for Sc. A brief discussion is given of the effect on the mean-field results of changes in volume or c/a ratio and of critical fluctuations. Since the physical mechanisms of these ideal...

  6. Hydrogen solubility in rare earth based hydrogen storage alloys

    Uchida, Hirohisa [Tokai Univ., Kanagawa (Japan). School of Engineering; Kuji, Toshiro [Mitsui Mining and Smelting Co. Ltd., Saitama (Japan)


    This paper reviews significant results of recent studies on the hydrogen storage properties of rare earth based AB{sub 5} (A: rare earth element, B: transition element) alloys The hydrogen solubility and the hydride formation, typically appeared in pressure-composition isotherms (PCT), are strongly dependent upon alloy composition, structure, morphology and even alloy particle size. Typical experimental results are shown to describe how these factors affect the hydrogen solubility and storage properties.

  7. Ferroelectricity of domain walls in rare earth iron garnet films.

    Popov, A I; Zvezdin, K A; Gareeva, Z V; Mazhitova, F A; Vakhitov, R M; Yumaguzin, A R; Zvezdin, A K


    In this paper, we report on electric polarization arising in a vicinity of Bloch-like domain walls in rare-earth iron garnet films. The domain walls generate an intrinsic magnetic field that breaks an antiferroelectric structure formed in the garnets due to an exchange interaction between rare earth and iron sublattices. We explore 180° domain walls whose formation is energetically preferable in the films with perpendicular magnetic anisotropy. Magnetic and electric structures of the 180° quasi-Bloch domain walls have been simulated at various relations between system parameters. Singlet, doublet ground states of rare earth ions and strongly anisotropic rare earth Ising ions have been considered. Our results show that electric polarization appears in rare earth garnet films at Bloch domain walls, and the maximum of magnetic inhomogeneity is not always linked to the maximum of electric polarization. A number of factors including the temperature, the state of the rare earth ion and the type of a wall influence magnetically induced electric polarization. We show that the value of polarization can be enhanced by the shrinking of the Bloch domain wall width, decreasing the temperature, and increasing the deviations of magnetization from the Bloch rotation that are regulated by impacts given by magnetic anisotropies of the films.

  8. Ferroelectricity of domain walls in rare earth iron garnet films

    Popov, A. I.; Zvezdin, K. A.; Gareeva, Z. V.; Mazhitova, F. A.; Vakhitov, R. M.; Yumaguzin, A. R.; Zvezdin, A. K.


    In this paper, we report on electric polarization arising in a vicinity of Bloch-like domain walls in rare-earth iron garnet films. The domain walls generate an intrinsic magnetic field that breaks an antiferroelectric structure formed in the garnets due to an exchange interaction between rare earth and iron sublattices. We explore 180° domain walls whose formation is energetically preferable in the films with perpendicular magnetic anisotropy. Magnetic and electric structures of the 180° quasi-Bloch domain walls have been simulated at various relations between system parameters. Singlet, doublet ground states of rare earth ions and strongly anisotropic rare earth Ising ions have been considered. Our results show that electric polarization appears in rare earth garnet films at Bloch domain walls, and the maximum of magnetic inhomogeneity is not always linked to the maximum of electric polarization. A number of factors including the temperature, the state of the rare earth ion and the type of a wall influence magnetically induced electric polarization. We show that the value of polarization can be enhanced by the shrinking of the Bloch domain wall width, decreasing the temperature, and increasing the deviations of magnetization from the Bloch rotation that are regulated by impacts given by magnetic anisotropies of the films.

  9. Rapidly solidified Mg-Al-Zn-rare earth alloys

    Chang, C.F.; Das, S.K.; Raybould, D.


    Among the light metal alloys, magnesium is the lightest structural material except for beryllium, and yet magnesium alloys have not seen extensive use because of their poor strength and corrosion resistance. Rapid solidification technology offers a possible solution to these problems. A number of Mg-Al-Zn alloys containing rare earth (RE) elements (e.g. Ce, Pr, Y, and Nd) have been investigated using rapid solidification processing for possible structural applications. The processing consists of planar flow or jet casting into ribbons, pulverization of ribbon to powder, and consolidation of powder into bulk shapes. The mechanical properties of some of these alloys show attractive combinations of strength, ductility and corrosion resistance. The microstructures of these alloys are correlated with their mechanical properties. The rapidly solidified Mg-Al-Zn-RE alloys show great potential for applications in automotive and aerospace industries. 7 references.

  10. Effect of surface deposited rare earth oxide gel characteristics on cyclic oxidation behavior of Fe20-Cr alloys

    Stela Maria Cristina Fernandes


    Full Text Available Rare earths have been used to increase high temperature oxidation resistance of many chromium dioxide and alumina forming alloys. These rare earths can be added as elements (or as oxide dispersions to the alloys or applied as an oxide coating to the alloy surface. The sol-gel technique is considered to be very efficient to apply fine oxide particle coatings. Oxide gel coatings of various rare earths such as lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, dysprosium, yttrium, erbium and ytterbium have been applied to an iron-chromium alloy to determine their influence on the cyclic oxidation behavior (RT-900 °C of the alloy. The morphology and coverage of the rare earth oxide gels varied with the type of rare earth. The cyclic oxidation resistance of the alloy increased with increase in time at temperature required to reach a specific chromium dioxide layer thickness and this in turn was influenced by the rare earth ion radius and characteristics of the rare earth oxide coating such as morphology, stability, coverage, resistance to thermal stresses and consequently adhesion.

  11. Effect of Annealing on Rare Earth Based Hydrogen Storage Alloys

    Li Jinhua


    Rare earth-based hydrogen storage alloy used as negative electrode materials for nickel-metal hydride (Ni-MH) batteries are used commercially.The effect of annealing treatment with different annealing temperature and time on the MLNi3.68 Co0.78 Mn0.35 Al0.27 and MMNi3.55 Co0.75 Mn0.40 Al0.30 alloys were investigated.The crystal microstructure,pressure-composition-isotherms (p-C-T) and electrochemical properties of alloys were examined by X-ray diffraction (XRD), automatic PCI monitoring system and electrical performance testing instruments.The optimum annealing treatment conditions of two kinds of alloys were determined.

  12. Effects of rare earths on friction and wear characteristics of magnesium alloy AZ91D

    祁庆琚; 刘勇兵; 杨晓红


    The influence of various rare-earth contents on the friction and wear characteristics of magnesium alloyAZ91D was studied. The results show that the wear resistance properties of rare-earth magnesium alloys are betterthan those of the matrix alloy under the testing conditions. Magnesium alloys undergo transition from mild wear tosevere wear. The addition of rare earths refines the structure of alloys, improves the comprehensive behaviors of themagnesium alloys, increases the stability of oxidation films on worn surfaces, enhances the loading ability of rare-earth magnesium alloys, and delays the transition from mild wear to severe wear effectively.

  13. Properties of rare-earth iron garnets from first principles

    Nakamoto, Ryan; Xu, Bin; Xu, Changsong; Xu, Hu; Bellaiche, L.


    Structural and magnetic properties of rare-earth iron garnets (RIG), which contain 160 atoms per unit cell, are systematically investigated for rare-earth elements varying from La to Lu (and including Y), by performing spin polarized density-functional calculations. The effects of 4 f electrons (as core or as valence electrons) on the lattice constant, internal coordinates, and bond lengths are found to be rather small, with these predicted structural properties agreeing rather well with available experiments. On the other hand, treating such electrons as valence electrons is essential to interpret the total magnetization measured in some RIG at low temperature, the different orientation and magnitude of the magnetizations that Fe and rare-earth ions can adopt and to also explain why some RIG have a compensation temperature while others do not. The magnetic exchange couplings and orbital-projected density of states are also reported for two representative materials, namely Gd3Fe5O12 and Nd3Fe5O12 , when accounting for their 4 f electrons.

  14. Preparation of hard magnetic materials based on nitrogenated rare-earth iron alloys; Preparacao de materiais magneticamente duros a base de ligas de terra rara - ferro nitrogenadas

    Guilherme, Eneida da Graca


    Nd Fe{sub 11}Ti, Nd Fe{sub 10.5} Mo{sub 1.5} and Nd Fe{sub 10.75} Mo{sub 1.25} alloys were synthesized by reduction-diffusion calciothermic process (RDC) from neodymium chloride (NdCl{sub 3}), iron, titanium, molybdenum and reduction agent (metallic calcium). The effect of process variables, like temperature, time, excess amount of NdCl{sub 3}, heating rate, and composition variation of the Nd Fe{sub 12-x}Mo{sub x} (1 {>=} x {>=} 2). Mother alloys in which 1:12 phase is major were nitrogenated by gas-solid reaction with N{sub 2} and by chemical reaction with sodium zide (Na N{sub 3}). In addition, the influence of reducing particle size of the powdered mother alloys in the nitrogenation step with Na N{sub 3} were studied. As prepared and interstitially modified Nd Fe{sub 11} Ti, Nd Fe{sub 10.5} Mo{sub 1.5} and Nd Fe{sub 10.75} Mo{sub 1.25} alloys with nitrogen , were characterized by X-ray diffraction, Moessbauer spectroscopy, thermomagnetic, SEM and EDS. Nitrogenation by gas-solid reaction with N{sub 2} is found to be not promising, since resulted Curie temperatures (Tc) were lower than literature values. However, nitrogenation by chemical reaction with Na N{sub 3} was efficient with higher or same Tc than previous reported results. The average increases on Tc and volumetric expansion were 200 deg C and 4%, respectively. Milling of the mother alloys before nitrogenation at 330 deg C is preferred because reaction kinetics is enhanced. Nevertheless, at 450 deg C, a competition between the interstitially modified compound formation (alloy + N) and alloy dissociation has occurred, resulting in a Fe-{alpha} phase increase. (author)

  15. Recovering heavy rare earth metals from magnet scrap

    Ott, Ryan T.; McCallum, Ralph W.; Jones, Lawrence L.


    A method of treating rare earth metal-bearing permanent magnet scrap, waste or other material in a manner to recover the heavy rare earth metal content separately from the light rare earth metal content. The heavy rare earth metal content can be recovered either as a heavy rare earth metal-enriched iron based alloy or as a heavy rare earth metal based alloy.

  16. Role of multi-microalloying by rare earth elements in ductilization of magnesium alloys

    Yuanding Huang


    Full Text Available The present work investigates the influences of microalloying with rare earths on the mechanical properties of magnesium alloys. The amount of each rare earth element is controlled below 0.4 wt.% in order not to increase the cost of alloy largely. The synergic effects from the multi-microalloying with rare earths on the mechanical properties are explored. The obtained results show that the as-cast magnesium alloys multi-microalloying with rare earths possesses a quite high ductility with a tensile strain up to 25–30% at room temperature. Moreover, these alloys exhibit much better corrosion resistance than AZ31 alloy. The preliminary in situ neutron diffractions on the deformation of these alloys indicate that the multi-microalloying with rare earths seems to be beneficial for the activation of more slip systems. The deformation becomes more homogeneous and the resultant textures after deformation are weakened.

  17. Friction and Wear Characteristics of Mg-Al Alloy Containing Rare Earths

    祁庆琚; 刘勇兵; 杨晓红


    The influence of rare earth on the friction and wear characteristics of magnesium alloy AZ91 and AM60 were studied. The results show that the wear resistance properties of rare earth magnesium alloys are better than those of matrix alloy under the testing conditions. The anti-wear behaviour of AZ91 alloy is much better than that of AM60 alloy. In dry sliding process,magnesium alloys undergo a transition from mild wear to severe wear. The addition of rare earths refine the structure of alloys, improve the comprehensive behaviors of magnesium alloys, increase the stability of oxidation films on worn surfaces, enhance the loading ability of rare earth magnesium alloys, and delay the transition from mild wear to severe wear effectively.

  18. Powder metallurgical processing of magnetostrictive materials based on rare earth-iron intermetallic compounds

    Malekzadeh, M.


    Procedures are described for fabrication of high density rare earth-iron magnetostrictive compounds by powder metallurgical techniques. The fabrication involves a sequence of steps which includes preparing the pre-alloyed compounds, pulverizing them into a fine powder, compacting in suitable sizes and shapes, and sintering. Samples prepared by these procedures are carefully characterized by scanning electron microscopy, x-ray diffraction, dilatometry, and magnetic measurements. Process steps are found to exert important influences upon densities, microstructure and magnetic properties attained after densification. Investigations on a number of these process steps, including milling time and medium, sintering, and magnetic powder alignment are described.

  19. A novel fused iron catalyst for ammonia synthesis promoted with rare earth gangue

    YU Xiujin; LIN Bingyu; LIN Jianxin; WANG Rong; WEI Kemei


    Rare earth gangue, which mainly consists of mixtures of fight rare earths such as lanthana, ceda, neodymium oxide and praseo-dymium oxide, was used as the promoter of fused iron catalysts for ammonia synthesis. The result showed that the activity of the catalyst promoted with rare earth gangue was comparable with those of commercial iron catalysts with high amount of cobalt. The role of rare earths was owed to their advantages for favoring the deep reduction of the main composite in catalyst, i.e., iron oxide. This finding indicated that the use of rare earth gangue could decrease the content of cobalt or even completely replace cobalt, which was used to be regarded as unsub-stitutable promoters for high performance ammonia catalyst; therefore, the cost of fused iron catalysts would decrease significantly.

  20. Effects of rare earth elements on the microstructure and properties of magnesium alloy AZ91D

    KaikunWang; KuiZhang; 等


    The effects of rare earth elements on the microstructure and properties of Magnesium alloy AZ91D alloy were studied.The different proportion of rare earth elements was added to the AZ91D and the tensile tests were carried out at different temperatures.The experimental results show that at room temperature or at 120℃ the AZ91D's decrease with the increasing amount of the rare earth elements.however,the ductility is improved.The influence of 0.14%Sb(mass fraction)on the AZ91D's strength is like that of rare earth elements(0.2%-0.4%)(mass fraction).Microstructure graphs demonstrate that appropriate amount of rare earth elements (0.1%-0.2%) can fine AZ91D's grain and improve its ductility.

  1. Effects of rare earth elements on the microstructureand properties of magnesium alloy AZ91D


    The effects of rare earth elements on the microstructure and properties of magnesium alloy AZ91D alloy were studied. The different proportion of rare earth elements was added to the AZ91D and the tensile tests were carried out at different temperatures. The experimental results show that at room temperature or at 120℃ the AZ91D's strength decrease with the increasing amount of the rare earth elements. However, the ductility is improved. The influence of 0.14%Sb (mass fraction) on the AZ91D's strength is like that of rare earth elements (0.2%-0.4%) (mass fraction). Microstructure graphs demonstrate that appropriate amount of rare earth elements (0.1%-0.2%) can fine AZ91D's grain and improve its ductility.

  2. Effect of rare earth elements on the microstructure and property for magnesium alloy AM60B


    The effects of rare earth elements on the microstructure and properties of magnesium alloy AM60B alloy were studied. Different proportions of rare earth elements were added to AM60B and the tensile tests were carried out under different temperatures. The experimental results show that at room temperature the tensile strength of AM60B can be improved with the addition of rare earth elements. The ductility of which at room or elevated temperature (120℃) can also be improved, and the ductility is to some extent in proportion with the amount of rare earth elements. The ductility at 120℃ is better than that at room temperature. The microstructure graphs demonstrate that appropriate amount of rare earth elements (0.1%-0.2%, mass fraction) can fine AM60B's grain and improve its ductility.

  3. Effect of Rare Earth Elements on Depositing Rate of Nickel Alloy Brush Plating Coating


    The effect of four kinds of rare earth elements on the depositing rate of Ni-based alloy brush plating coatings was investigated. The results indicate that all of the selected rare earth elements increase the depositing rate of Ni-based alloy coatings, and Sm increases the depositing rate most obviously. There is an optimum amount of rare earth addition in the plating solution. With the change of plating voltage to a certain extent, the results reveal no differences. The mechanism of the increase of the depositing rate was analyzed.

  4. Effects of Rare Earths on Properties of Ti-Zr-Cu-Ni Base Brazing Filler Alloys

    Ma Tianjun; Kang Hui; Wu Yongqin; Qu Ping


    The effects of the addition of rare earths on the properties of Ti-Zr-Cu-Ni base brazing filler alloys and the mechanical microstructure and properties were studied for the brazed-joints in the vacuum brazing of TC4 by comparing synthetical properties of two kinds of filler metals.The results indicate that the filler metals added with rare earths have lower melting point, better wettability and higher mechanical properties in the brazing joints.

  5. Modification Mechanism of Rare Earth Elements in ZA27 Casting Alloys

    刘贵立; 李荣德


    The model of the liquid-phase ZA27 alloys was set up by molecular dynamics theory. The atomic structure of phase, RE-compounds, and the phase-liquid interface in ZA27 alloys were constructed by computer programming. Electronic structures of phase with rare earth elements dissolved and of phase-liquid interfaces with rare earth elements enrichment in ZA27 casting alloys were investigated by using the Recursion method. The ESE energy of RE elements and the structure energy of RE-compounds, phase, and the liquid-phase ZA27 alloys were calculated. The results show that rare earth elements are more stable to be in the phase interface than in phase, which explains the fact of very small solid so lubility of rare earth elements in phase, and the enrichment in the solid-liquid growth front. This makes dendrite melt and break down, dissociate and propagate. RE-compounds can act as heterogeneous nuclei for phase, leading to phase refinement. All above elucidates the modification mechanism of rare earth elements in zinc-aluminum casting alloys at electronic level.

  6. Effect of Rare Earth Metals on the Microstructure of Al-Si Based Alloys

    Saleh A. Alkahtani


    Full Text Available The present study was performed on A356 alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the alloy melting temperature with no marked change in the temperature of Al-Si eutectic precipitation. Additionally, rare earth metals have no modification effect up to 1.5 wt %. In addition, La and Ce tend to react with Sr leading to modification degradation. In order to achieve noticeable modification of eutectic Si particles, the concentration of rare earth metals should exceed 1.5 wt %, which simultaneously results in the precipitation of a fairly large volume fraction of insoluble intermetallics. The precipitation of these complex intermetallics is expected to have a negative effect on the alloy performance.

  7. Effect of Rare Earth Elements on Anisotropy and Microstructure of Al-Li Alloy 2195 Sheets


    For the purpose of decreasing the applied limitation resulting from the anisotropic mechanical property of Al-Li alloy 2195, this study employed a complex heat treatment process, involving the pre-tension, thermo-infiltration of the rare earth element Ce, solution treatment, and artificial aging technology. The results indicate that the infiltration of rare earth element Ce benefits the abatement of anisotropy of Al-Li alloy 2195 sheet, in contrast with that of the normal heat treatment process. The gradient of the Vickers-hardness decreases at least 50% through the thickness, and the tensile strength in the rolling direction also increases significantly. If Ce was infiltrated into the alloy under the optimum pre-deformation, the yield strength (σ0.2) increased by 30 MPa while the tensile strength (σb) enhanced by 25 MPa compared to the rare earth free samples. Meanwhile, the fractography illustrated that the fracture surface of the sample became more desirable.

  8. The effect of rare earth elements on the microstructure of as-cast AM50 alloy

    A. Żydek


    Full Text Available As-cast Mg-5Al-0.4Mn-xRE (x = 0, 1, 2 wt.% magnesium alloys were prepared successfully and influence of rare earth (RE elements on the microstructure has been investigated by light microscopy and X-ray diffraction (XRD. The results revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. With the addition of rare earth elements Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitates increased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased. Additionally, in alloys with rare earth elements no aluminium-manganese precipitates were observed, instead of that ternary intermetallic compound Al10RE2Mn7 was formed.

  9. Effect of Rare Earth Metals on the Microstructure of Al-Si Based Alloys

    Alkahtani, Saleh A.; Elgallad, Emad M.; Tash, Mahmoud M.; Samuel, Agnes M.; Samuel, Fawzy H.


    The present study was performed on A356 alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the alloy melting temperature with no marked change in the temperature of Al-Si eutectic precipitation. Additionally, rare earth metals have no modification effect up to 1.5 wt %. In addition, La and Ce tend to react with Sr leading to modification degradation. In order to achieve noticeable modification of eutectic Si particles, the concentration of rare earth metals should exceed 1.5 wt %, which simultaneously results in the precipitation of a fairly large volume fraction of insoluble intermetallics. The precipitation of these complex intermetallics is expected to have a negative effect on the alloy performance. PMID:28787844

  10. Effect of Rare Earth on Superplasticity of Zn-5Al Eutectic Alloy

    石志强; 叶以富; 李世春; 王焕荣; 滕新营


    The superplastic deformation curves of Zn-5Al eutectic alloy containing small amount of rare earth were measured, and the influence of rare earth on structure and superplasticity characteristics of the alloy was examined with optical microscope, XDF and TEM. The results show that the elongation of Zn-5Al eutectic alloy can be increased if less than 0.2 %(mass fraction) misch-metal was added. Rare earth which exists in the form of compounds Al2CeZn2 and CeZn3 can refrain the dissolution and diffusion of Zn to Al and postpone the saturation of the diffusion-dissolution zone(DDZ) above 350 ℃, and in such a way boost up α/β interface sliding which benefits the superplasticity.

  11. Effect of Rare Earth Metals on the Microstructure of Al-Si Based Alloys.

    Alkahtani, Saleh A; Elgallad, Emad M; Tash, Mahmoud M; Samuel, Agnes M; Samuel, Fawzy H


    The present study was performed on A356 alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the alloy melting temperature with no marked change in the temperature of Al-Si eutectic precipitation. Additionally, rare earth metals have no modification effect up to 1.5 wt %. In addition, La and Ce tend to react with Sr leading to modification degradation. In order to achieve noticeable modification of eutectic Si particles, the concentration of rare earth metals should exceed 1.5 wt %, which simultaneously results in the precipitation of a fairly large volume fraction of insoluble intermetallics. The precipitation of these complex intermetallics is expected to have a negative effect on the alloy performance.

  12. Investigation on Behavior of Rare Earth Element Cerium in Aluminum-Lithium Alloys by Internal Friction Method


    The behavior of rare earth element Ce in 2090 Al-Li alloys was studied by the method of low frequency internal friction.The results showed that rare earth element Ce can increase the activation energy of grain boundary and improve the grain boundary strength of alloys.Rare earth element Ce can decrease the tendency of softening of elastic modulus of 2090 Al-Li alloys after heat cycle and keep high elastic modulus of initial state.

  13. Development of Strip Casting Technology in Rare Earth Permanent Magnet Alloys and Hydrogen Storage Alloys in China

    Han Weiping; Guo Binglin; Yu Xiaojun; Zhu Jinghan; Cheng Xinghua


    The SC technique is now being applied widely in material preparation, especially in rare earth functional materials in virtue of its advanced process and high performance product. The applications of SC technique in rare earth permanent magnet alloys and hydrogen storage alloys were analyzed integrative, on the basis of summary of SC technique development in this paper. The paper mainly includes development history of SC technology, effect of SC technology on alloy microstructure, application of SC technology in RE storage hydrogen alloy and sintered Nd-Fe-B alloy, development of SC equipment and SC product industry. At the same time, the paper points out the existing problem of SC products.

  14. Effect of Rare Earth Metals on Structure and Properties of Electroless Co-B Alloy Coating

    宣天鹏; 张雷; 黄秋华


    The effect of rare earth metals cerium, lanthanum and yttrium on chemical composition, structure and properties of electroless Co-B alloy coating was studied. By plasma transmitting spectrograph, electron energy spectrometer, X-ray diffractometter, micro-hardometer and vibratory sample magnetometer the chemical constitution, structure and properties of the alloy coatings were analyzed and inspected. The results show that with a tiny quantity of rare earth metal added into Co-B alloy coating, the content of boron is decreased in the alloy coatings, and the kinds of rare earth metal have enormous effect on the structure and properties of electroless Co-B alloy coating. At the same time electroless Co-B alloy with amorphous structure is transformed to electroless Co-B-RE alloy with microcrystalline or crystalline structure. In this way microhardness of the coatings is increased remarkably. Cerium and lanthanum would also increase the saturated magnetic intensity and decrease coercitive force of the coating. So soft magnetization of the coatings would be improved.

  15. Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies

    Brachetti S, S. B. [Instituto Tecnologico de Ciudad Madero, Av. 1o. de Mayo y Sor Juana I. de la Cruz, Col. Los Mangos, 89440 Ciudad Madero, Tanaulipas (Mexico); Dominguez C, M. A.; Torres H, A. M.; Onofre B, E. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Altamira, Carretera Tampico-Puerto Industrial Altamira Km. 14.5, 89600 Altamira, Tamaulipas (Mexico); De la Cruz H, W., E-mail: [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 2681, 22800 Ensenada, Baja California (Mexico)


    The present work is aimed to investigate the corrosion resistance of rare earth protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO{sub 3}){sub 3} and La(NO{sub 3}){sub 3} solutions by varing parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization. Chemical and morphological characterizations of the surface before and after electrochemical evaluations were performed by X-ray photoelectron spectroscopy and scanning electron microscopy. (Author)

  16. New approaches for rare earth-magnesium based hydrogen storage alloys

    Huaiwei Zhang


    Full Text Available As the most possibility applied to the next generation negative electrode materials of Ni/ MH second battery, rare earth (RE-magnesium (Mg based alloys have been developed over the last few years. Recent advances about the RE-Mg based intermetallic compounds on the crystal structures, hydrogenation behaviors and electrochemical performances are reviewed in the paper. On the other hand, new results about the preparation and modification methods of the alloys are also covered in details.

  17. Rare earth oxide coatings to decrease high temperature degradation of chromia forming alloys

    Stela Maria de Carvalho Fernandes


    Full Text Available The addition of small quantities of reactive elements such as rare earths (RE to chromia or alumina forming alloys improves the high temperature oxidation resistance. Traditionally, these elements are alloying additions or are added as oxides to form a dispersion. The alloys can also be coated with RE oxides. Several methods can be used to coat alloy substrates with RE oxides and the sol-gel process is considered to be quite efficient, as it generates the very small oxide particles. This paper presents the influence of surface coatings of Ce, La, Pr, and Y oxide gels on the oxidation behavior of an Fe-20Cr alloy at 1000 °C. The morphology of the rare earth (RE oxide coatings varied with the nature of RE. The oxidation rate of RE oxide coated Fe-20Cr was significantly less than that of the uncoated alloy. The extent of influence the RE oxide coating exercised on the oxidation rate decreased in the following order: La, Ce, Pr, Y. The scale formed in the presence of RE oxide was very thin, fine grained and adherent chromia. A direct correlation between rare earth ion radius and the extent of influence on chromia growth rate at 1000 °C was observed.

  18. Progress in bulk MgCu2-type rare-earth iron magnetostrictive compounds

    Ren Wei-Jun; Zhang Zhi-Dong


    Studies of bulk MgCu2-type rare-earth iron compounds with Laves phase are reviewed.The relationship between magnetostriction and structural distortion and the consequent crystallographic method for measuring magnetostriction are introduced at first.Then we review recent progress in understanding bulk magnetostrictive Laves phase materials,especially the magnetostriction and the minimization of the anisotropy of the light rare-earth Pr-and Sm-based compounds.Finally,a summary and outlook for this kind of compounds are presented.

  19. Strengthening and Toughening Design and Development of Mg-Rare Earth Alloys

    ZENG Xiaoqin


    Full Text Available Magnesium alloys are the lightest structural alloys developed so far and have a great potential for lightweight applications, ranging from portable electronic devices to automobile parts. Comparing to Mg alloys containing no rare earth (RE, Mg-RE alloys attracted more and more attentions due to the higher strengths at both room temperature and elevated temperature. Strengthening methods for Mg alloys with high RE contents and low RE contents were introduced respectively in this paper. For Mg alloys with high RE contents, precipitates of β' lying in the triangular prismatic plates can impede dislocation slip effectively to enhance the strength of the alloy. For Mg alloys with low RE contents, the microstructure containing nano grains in the surface layer and twinning in the center can be obtained by surface mechanical attrition treatment. Thus the Mg alloy can be strengthened by both refinement strengthening of nano grains and twinning strengthening of RE segregated twin boundaries.

  20. Effect of rare earths on corrosion resistance of Cu-30Ni alloys in simulated seawater

    毛向阳; 方峰; 蒋建清; 谈荣生


    Cu-30Ni-xRE(x=0-0.213 wt.%) alloy was prepared by adding rare earths(RE) in melted Cu-30Ni alloy using metal mould casting method.The effects of RE on corrosion resistance of the alloy in simulated seawater were investigated using optical microscope,scanning electronic microscope with energy-dispersive spectrometer and electrochemical measurement system.The results showed that the corrosion resistance of Cu-30Ni alloy was greatly improved by adding proper amount of RE,whereas excess addition of RE worsened ...

  1. Effects of rare earths on the microarc oxidation of a magnesium alloy

    LI Jianzhong; TIAN Yanwen; CUI Zuoxing; HUANG Zhenqi


    The effects of rate earths on the properties of the microarc oxidation (MAO) coating on a magnesium alloy were investigated by means of scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS),and electrochemistry methods.The results show that a nice and compact MAO coating was successfully obtained when the magnesium alloy was treated in nitrate solutions as the pre-treatment of MAO.However,the MAO was not successfully completed for the silicate electrolytes with the addition of rare earths.After the magnesium alloy being treated by rare earth nitrate,the obtained MAO coating has advantages such as uniform distribution of thickness,improved corrosion resistance,and nice-uniform surface,as compared with the untreated magnesium alloy.In addition,the time of non-ESP,the voltage and current density of the MAO process obviously decrease.Cerium oxide doped on the surface of the magnesium alloy can significantly improve the corrosion resistance of the MAO coating and decrease the current density of the MAO process,as compared with lanthanum oxide,whereas the doped rare earths have no significant effect on the components of the MAO coating.

  2. Crystal Fields in Dilute Rare-Earth Metals Obtained from Magnetization Measurements on Dilute Rare-Earth Alloys

    Touborg, P.; Høg, J.


    Crystal field parameters of Tb, Dy, and Er in Sc, Y, and Lu are summarized. These parameters are obtained from magnetization measurements on dilute single crystals, and successfully checked by a number of different methods. The crystal field parameters vary unpredictably with the rare-earth solute....... B40, B60, and B66 are similar in Y and Lu. Crystal field parameters for the pure metals Tb, Dy, and Er are estimated from the crystal fields in Y and Lu....

  3. Influence of rare earth metals on the nucleation and solidification behavior of iron and 1045 steel

    Li, H.; McLean, A.; Rutter, J. W.; Sommerville, I. D.


    Two series of experiments have been conducted to determine the influence of rare earth additions on the nucleation and crystallization behavior of pure iron and 1045 steel. In the first series, additions of rare earth suicide or cerium dioxide powder to two-Kg 1045 steel ingots indicated that rare earth suicide can refine the as-cast structure of such ingots. However, if the holding time after rare earth silicide addition is over two minutes, the grain refinement decreases. With cerium dioxide additions, a relatively large columnar zone was obtained. In the second series, the effects of cerium metal or cerium dioxide powder additions on the degree of undercooling obtainable in pure iron and 1045 steel were examined by the lévitation melting method. Surface tension measurements of the levitated droplets were carried out at the same time to investigate the possible effects of surface tension variations on the nucleation and crystallization behavior of the metals. The experimental data show that rare earth inclusions can greatly reduce the degree of undercooling of iron and steel, and that a small amount of dissolved cerium can further reduce the degree of undercooling of levitated droplets. The structure and reaction products obtained with Fe-Ce levitated droplets were examined with both optical and scanning electron microscopy as well as X-ray diffraction analysis. The experimental results clearly indicated that cerium solute redistribution during solidification is the dominant factor in refining the as-cast structure. A nucleation and solidification model for the Fe-Ce levitated droplets has been developed, which can successfully explain the experimental results.



    Force Base, Dayton OH, March 20th 2013 23. Informatics Aided Discovery of Energy Materials 2013 Kentucky Workshop on Renewable Energy and Energy ...AFRL-AFOSR-VA-TR-2016-0122 Sustainable Alloy Design Searching for Rare Earth Element Alternatives through Crystal Engineering Krishna Rajan IOWA...reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching

  5. Study of rare earth element effect on microstructures and mechanical properties of an Al-Cu-Mg-Si cast alloy

    WAN Weiwei; HAN Jianmin; LI Weijing; WANG Jinhua


    The improvements of microstructures and properties of a high strength aluminum cast alloy were studied.The effects of rare earth elements on the microstructures and mechanical properties of the high strength cast alloy Al-Cu-Mg-Si were investigated.The result shows that the addition of rare earth elements can change the microstructures in refining the grain size of the alloy and making the needle-like and laminar eutectic Si to a granular Si.With the increase of the rare earth, the tensile strength and elongation of the alloy increase first and then fall down.The mechanical properties of the alloy will reach the highest value when the content of rare earth elements is about 0.7%.

  6. Influence of rare earths on shrinkage porosity in thin walled ductile cast iron

    Pedersen, Karl Martin; Tiedje, Niels Skat


    Ductile cast iron has been cast in test bars with thickness from 2 to 10 mm. The rare earth elements La and Ce have been added to some of the castings to evaluate their influence on microstructure and shrinkage tendency. Both La and Ce increased the graphite nodule count, especially for thickness...... the temperature T-1, which is controlled by the growth of off-eutectic austenite dendrites, increased the shrinkage tendency....

  7. The effects of solidification and atomization on rare-earth alloys

    Anderson, Iver E.; Osborne, M. G.; Ellis, T. W.


    This article discusses the results of experiments involving the application of atomization techniques to the production of three selected rare-earth intermetallic (REI) materials. High-pressure gas atomization and centrifugal atomization into a rotating quench bath have been used to process the alloys. Rapid-solidification processing by atomization techniques is of great benefit since optimum performance of these REI materials demands chemical and structural homogeneity. The results demonstrate that such careful solidification microstructure control is required if the benefits of REI-alloy properties are to be realized with maximum processing efficiency.

  8. Structural transformation studies on the rare earth containing Heusler alloys Pd 2RESn

    Umarji, A. M.; Malik, S. K.; Shenoy, G. K.


    The Heusler alloys Pd 2RESn form for rare-earths (RE) from Tb to Lu and for Sc and Y. Of these, the alloys containing Yb, Tm, Lu, Sc and Y are superconducting. We have carried out structural studies on all these alloys by studying the temperature dependence of the X-ray patterns in the temperature range 5 to 300 K. Some nonstoichiometric compositions were also investigated. Structural transformation is observed only in Tb and Dy containing alloys while none of the superconducting alloys show a transformation. The transformation temperature is lowered by about 50 K in going from stoichiometric Pd 2TbSn to nonstoichiometric Pd 2Tb 0.95Sn while it is completely suppressed in Pd 2Dy 0.95Sn. Magnetic and Mössbauer studies on Dy compound are also reported.

  9. Thermal oxidation of the surface of binary aluminum alloys with rare-earth metals

    Akashev, L. A.; Popov, N. A.; Kuznetsov, M. V.; Shevchenko, V. G.


    The kinetics of oxidation of the surface of Al alloys with 1-2.5 at % rare-earth metals (REMs) at 400-500°C in air was studied by ellipsometry and X-ray photoelectron spectroscopy (XPS). The addition (1-2.5 at % REM) of all rare-earth metals to aluminum was shown to increase the thickness of the oxide layer. The addition of surfactant and chemically active REMs (Yb, Sm, La, and Ce) increased the rate of oxidation of solid aluminum most effectively. The oxidation can be accelerated by the polymorphic transformations of the individual REM oxides in the film. The surface activity of Sm with respect to solid Al was confirmed by XRS.

  10. Assessing the utility of trace and rare earth elements as biosignatures in microbial iron oxyhydroxides

    Christine eHeim


    Full Text Available Microbial iron oxyhydroxides are common deposits in natural waters, recent sediments and mine drainage systems and often contain significant accumulations of trace and rare earth elements (TREE. TREE patterns are widely used to characterize minerals and rocks, and to elucidate their evolution and origin. Whether and which characteristic TREE signatures distinguish between a biological and an abiological origin of iron minerals is still not well understood. Long-term flow reactor studies were performed in the Äspö Hard Rock Laboratory to investigate the development of microbial mats dominated by iron-oxidizing bacteria, namely Mariprofundus sp. and Gallionella sp. The experiments investigated the accumulation and fractionation of TREE under controlled conditions and enabled us to assess potential biosignatures evolving within the microbial iron oxyhydroxides. Concentrations of Be, Y, Zn, Zr, Hf, W, Th, Pb, and U in the microbial mats were 1e3- to 1e5-fold higher than in the feeder fluids whereas the rare earth elements and Y (REE+Y contents were 1e4 and 1e6 fold enriched. Except for a hydrothermally induced Eu anomaly, the normalized REE+Y patterns of the microbial iron oxyhydroxides were very similar to published REE+Y distributions of Archaean Banded Iron Formations. The microbial iron oxyhydroxides from the flow reactors were compared to iron oxyhydroxides that were artificially precipitated from the same feeder fluid. These abiotic and inorganic iron oxyhydroxides show the same REE+Y distribution patterns. Our results indicate that the REE+Y mirror quite exactly the water chemistry, but they do not allow to distinguish microbially mediated from inorganic iron precipitates. All TREE studied showed an overall similar fractionation behavior in biogenic, abiotic and inorganic iron oxyhydroxides. Exceptions are Ni and Tl, which were only accumulated in the microbial iron oxyhydroxides and may point to a potential usage of these elements as

  11. Effects of Rare Earth and Alkaline Earth on Spheroidizing of Eutectic Carbides in Low Tungsten White Cast Iron

    Fu Hanguang; Zou Dening


    Tungsten Alloy White Cast Iron(TAWCI) has great brittleness and narrow application scope. The influences of Rare earth element(Ce) and alkaline earth elements ( K, Na) on the microstructures and performances of TAWCI were researched, and the idea estimating spheroidizing effect of carbides using Circular Degree (C. D) were put forward. The result shows that eutectics carbide tums into sphericity from network after modification, and carbide is refined and uniformly distributed and the C. D of eutectic carbide increases. The mechanism of carbide spheroidizing was analyzed. The impact toughness and wear resistance of TAWCI obviously improve with the rise of C. D of carbides.The service life of modified TAWCI roll is 35 % higher than that of high chromium cast iron roll, and its production cost is reduced by 25 %.

  12. In vitro biocompatibility and endothelialization of novel magnesium-rare Earth alloys for improved stent applications.

    Nan Zhao

    Full Text Available Magnesium (Mg based alloys are the most advanced cardiovascular stent materials. This new generation of stent scaffold is currently under clinical evaluation with encouraging outcomes. All these Mg alloys contain a certain amount of rare earth (RE elements though the exact composition is not yet disclosed. RE alloying can usually enhance the mechanical strength of different metal alloys but their toxicity might be an issue for medical applications. It is still unclear how RE elements will affect the magnesium (Mg alloys intended for stent materials as a whole. In this study, we evaluated MgZnCaY-1RE, MgZnCaY-2RE, MgYZr-1RE, and MgZnYZr-1RE alloys for cardiovascular stents applications regarding their mechanical strength, corrosion resistance, hemolysis, platelet adhesion/activation, and endothelial biocompatibility. The mechanical properties of all alloys were significantly improved. Potentiodynamic polarization showed that the corrosion resistance of four alloys was at least 3-10 times higher than that of pure Mg control. Hemolysis test revealed that all the materials were non-hemolytic while little to moderate platelet adhesion was found on all materials surface. No significant cytotoxicity was observed in human aorta endothelial cells cultured with magnesium alloy extract solution for up to seven days. Direct endothelialization test showed that all the alloys possess significantly better capability to sustain endothelial cell attachment and growth. The results demonstrated the promising potential of these alloys for stent material applications in the future.

  13. Examination of Sarikaya(Yozgat-Turkey) iron mineralization with rare earth element(REE) method

    Nursel; OKSUZ; Sukru; KOC


    Iron mineralizations in the study area are found in amphibolites in the localities of Buyukoren,Uzunkuyu-Atkayasi,and Karabacak and they display a predominantly banded texture.Their paragenesis is dominated by magnetite and hematite.In this study,iron mineralizations in Sarikaya were examined in terms of rare earth element(REE) contents and attempts were made to determine some physicochemical conditions that had an impact upon their formation.For this purpose,42 ore samples and 17 enriched magnetite samples...

  14. Preparation and Performance of Rare Earths Chemical Conversion Film on Magnesium Alloy


    Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morphology and performance of the conversion film were analyzed by means of SEM and electrochemical method. Formation dynamics about cerium conversion film on magnesium alloy in solution containing cerium salt and the anti-corrosion behavior of the conversion film in 3.5% NaCl solution were studied by electrochemical method respectively. The results shows that the conversion film is more compact at room temperature when concentration of cerium sulfate is 10 g·L-1 in the solution; the open circuit potential of the magnesium sample moves up to positive direction about 100 mV, the surface of conversion film becomes even and lustrous, and the adhesion intensity of conversion film increases when adding aluminum nitrate into the solution containing cerium salt. The pH value of the solution and immersion time of the sample in the solution also affect the surface morphology and anti-corrosion property of the conversion film. After covered by rare earths conversion film, the anti-corrosion property of magnesium alloy is obviously improved. Rare earth conversion film has self-repairing capability in corrosion medium.

  15. Study on Nanocrystalline Rare Earth Mg-Based System Hydrogen Storage Alloys with AB3-Type


    A sort of rare earth Mg-based system hydrogen storage alloys with AB3-type was prepared by double-roller rapid quenching method. The alloys were nanocrystalline multi-phase structures composed of LaNi3 phase and LaNi5 phase by X-ray diffraction and scanning electron microscopy analyses, and the suitable absorption/desorption plateau was revealed by the measurement of P-C-I curve. Electrochemical studies indicate that the alloys exhibit good electrochemical properties such as high capacity and stable cycle life, and the discharge capacity is 369 mAh·g-1 at 0.2 C (72 mA·g-1), after 460 cycles, the capacity decay was only 19.4% at 2 C (720 mA·g-1).

  16. Effects of Aging Treatment on Laser-Welded Mg-Rare Earth Alloy NZ30K

    Jun Dai


    Full Text Available Magnesium-rare earth alloys have received extensive attention due to their attractive mechanical properties resulting from high density of precipitation. The precipitation sequence in laser-welded Mg-3Nd-0.2Zn-0.4Zr (NZ30K alloy during aging treatment at 200°C and 225°C has been investigated using transmission electron microscopy (TEM. The results indicate that the tensile strength of laser-welded NZ30K can be improved significantly after aging treatment at 200°C for 8 h. It is found that the precipitation in laser-welded NZ30K alloy follows the sequence of supersaturated solid solution → β′′(DO19 → β′(fcc.

  17. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys

    Kwo-Hsiung Young


    Full Text Available Effects of substitutions of rare earth (RE elements (Y, La, Ce, and Nd to the Zr-based AB2 multi-phase metal hydride (MH alloys on the structure, gaseous phase hydrogen storage (H-storage, and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15 are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation and is recommended for all the AB2 MH alloys for electrochemical applications.

  18. Endothelialization of novel magnesium-rare earth alloys with fluoride and collagen coating.

    Zhao, Nan; Workman, Benjamin; Zhu, Donghui


    Magnesium (Mg) alloys are promising scaffolds for the next generation of cardiovascular stents because of their better biocompatibility and biodegradation compared to traditional metals. However, insufficient mechanical strength and high degradation rate are still the two main limitations for Mg materials. Hydrofluoric acid (HF) treatment and collagen coating were used in this research to improve the endothelialization of two rare earth-based Mg alloys. Results demonstrated that a nanoporous film structure of fluoride with thickness of ~20 µm was formed on the Mg material surface, which improved the corrosion resistance. Primary human coronary artery endothelial cells (HCAECs) had much better attachment, spreading, growth and proliferation (the process of endothelialization) on HF-treated Mg materials compared to bare- or collagen-coated ones.

  19. Endothelialization of Novel Magnesium-Rare Earth Alloys with Fluoride and Collagen Coating

    Nan Zhao


    Full Text Available Magnesium (Mg alloys are promising scaffolds for the next generation of cardiovascular stents because of their better biocompatibility and biodegradation compared to traditional metals. However, insufficient mechanical strength and high degradation rate are still the two main limitations for Mg materials. Hydrofluoric acid (HF treatment and collagen coating were used in this research to improve the endothelialization of two rare earth-based Mg alloys. Results demonstrated that a nanoporous film structure of fluoride with thickness of ~20 µm was formed on the Mg material surface, which improved the corrosion resistance. Primary human coronary artery endothelial cells (HCAECs had much better attachment, spreading, growth and proliferation (the process of endothelialization on HF-treated Mg materials compared to bare- or collagen-coated ones.

  20. Galvanic corrosion of rare earth modified AM50 and AZ91D magnesium alloys coupled to steel and aluminium alloys

    Mohedano, M.; Arrabal, R.; Pardo, A.; Paucar, A.; Merino, M. C.; Matykina, E.; Mingo, B.; Garces, G.


    Electrochemical and gravimetric measurements were used to examine the effects of neodymium and gadolinium additions on the galvanic corrosion behaviour of AM50 and AZ91D magnesium alloys coupled to A 570 Gr 36 carbon steel and AA2011-AA6082 aluminium alloys. Rare earth modified alloys showed Al{sub 2}Nd/Al{sub 2}Gd and Al-Mn-Nd/Al-Mn-Gd intermetallics, reduced area fraction of {beta}-Mg{sub 1}7Al{sub 1}2 phase and increased corrosion resistance due to increased surface passivity and suppression of micro-galvanic couples. Neodymium and gadolinium additions improved the galvanic corrosion resistance of AM50 alloy, but were less effective in case of the AZ91D alloy. The AA6082 alloy was the most compatible material and the AA2011 alloy was the least compatible. (Author)

  1. A modified Johnson-Cook constitutive relationship for a rare-earth containing magnesium alloy

    陈道伦; 李德江; 曾小勤


    Lightweight magnesium alloy has recently attracted a considerable interest in the automotive and aerospace industries to improve fuel efficiency and reduce CO2 emissions via the weight reduction of vehicles. Rare-earth (RE) element addition can re-markably improve the mechanical properties of magnesium alloys through weakening crystallographic textures associated with the strong mechanical anisotropy and tension-compression yield asymmetry. While the addition of RE elements sheds some light on the alteration in the mechanical anisotropy, available information on the constitutive relationships used to describe the flow behavior of RE-containing magnesium alloys is limited. To establish such a constitutive relationship, uniaxial compressive deformation tests were first conducted on an extruded Mg-10Gd-3Y-0.5Zr (GW103K) magnesium alloy at the strain rates ranging from 1×10-1 to 1×10-4 s-1 at room temperature. A modified Johnson-Cook constitutive equation based on a recent strain hardening equation was proposed to predict the flow stresses of GW103K alloy. Comparisons between the predicted and experimental results showed that the modified Johnson-Cook constitutive equation was able to predict the flow stresses of the RE-containing magnesium alloy fairly accurately with a standard deviation of about 1.8%.

  2. Effects of rare earth elements addition on microstructures, tensile properties and fractography of A357 alloy

    Jiang, Wenming, E-mail: [State Key Lab of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Mechanical and Electrical Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Fan, Zitian; Dai, Yucheng; Li, Chi [State Key Lab of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)


    The effects of rare earth (RE) containing Ce and La elements addition on the microstructures characteristics, tensile properties and fracture behavior of A357 alloy under as-cast and T6 conditions were systematically investigated in this study. Obtained results showed that the addition of RE obviously reduced the sizes of the α-Al primary phase and eutectic silicon particles as well as SDAS value and improved the morphology of eutectic silicon particles. The optimum level of added RE content were 0.2 wt%, and the aspect ratio of eutectic silicon particles of the A357 modified alloy under as-cast and T6 conditions decreased 142% and 174%, respectively, compared with the unmodified alloy. In addition, the addition of RE greatly improved the tensile properties of A357 alloy as result of the significant improvement in microstructure, especially in elongation under T6 condition. The fracture surfaces of the A357 unmodified alloy tensile samples showed a clear brittle fracture nature, and its fracture path passed through the eutectic silicon particles and displayed a transgranular fracture mode, leading to poorer ductility. The fracture path of the A357 modified alloys passed through the eutectic phase along the grain boundaries of the α-Al primary phase, and the fracture generated by dimple rupture with cracked eutectic silicon particles, and it showed an intergranular fracture mode, resulting in superior ductility.

  3. A rare earth alloy as a synthetic reagent: contrasting homo metallic rare earth and hetero bimetallic outcomes

    Deacon, G.B.; Forsyth, C.M.; Junk, P.C.; Leary, S.G. [Monash Univ., School of Chemistry, Clayton (Australia)


    Reaction of LaNi{sub 5} with 2,2'-dipyridyl-amine (HNpy{sub 2}) at 170 C under vacuum gave crystals of dimeric [La(Npy{sub 2}){sub 3}]{sub 2} as a previously unknown eight-coordinate isomer (1a) (two {mu}-{eta}{sup 2}:{eta}{sup 2} and two terminal chelating (Namide,Npy) Npy{sub 2} ligands), which reverts to the known ten coordinate isomer (1b) on recrystallization from THF/PhMe, thereby establishing linkage isomerism of a [Ln(Npy{sub 2}){sub 3}]{sub 2} complex for the first time. Reaction of 8-hydroxyquinoline (HOQ) with excess LaNi{sub 5} alloy at 190 C resulted in extraction of both metals and the formation of hetero-bimetallic [Ni{sub 2}La(OQ){sub 7}] (2). The trinuclear complex has two terminal, fac-octahedral nickel(II) sites, each bound to three chelating 8-quinolinolate anions which bridge through the oxygen atoms to the lanthanum(III) centre. The eight-coordinate lanthanum environment is completed by a chelating OQ ligand. (authors)

  4. Influence of Rare Earths on Improve Impact Property of Structural Alloy Steel with Extra Low Sulfur and Oxygen

    Guo Feng; Lin Qin


    The influence of rare earth lanthanum and cerium on impact property of structural alloy steel with extra low sulfur and oxygen was studied by impact test and microanalysis. The results showed that rare earths increased impact power of the steel when their contents were about 0.005%. Proper addition of rare earths could purify grain boundaries and decrease amount of inclusions, and reduced the possibility of crack growth along grain boundaries and through inclusions. Therefore, such steel could absorb more crack growth energy while it was impacted. However, if the content of rare earths is excessive, the grain boundary would be weakened and brittle-hard phosphates and Fe-RE intermetallic would be formed, which worsened impact toughness of steel.

  5. Research on rare earth and iron-rich diamond-enhanced tungsten carbide composite button

    SHI Xiaoliang; SHAO Gangqin; DUAN Longchen; YUAN Runzhang


    At the present time in china, the binder used in tungsten carbide composite button is mainly cobalt, which is very expensive. In order to solve the problems, a new type of rare earth and iron-rich diamond-enhanced tungsten carbide with high abrasive resistance and high toughness against impact, which realizes to substitute ferrum for cobalt, has been developed. The key problems in making the button are to improve the mechanical properties of matrix and increase the welding strength between the diamond and the matrix. All these problems have been solved effectively by low temperature activation hot-press sintering, doping rare earth lanthanum in matrix and high sintering pressure. The properties of the button have been determined under laboratory conditions. The test results show that its hardness is more than 90 HRA, its abrasive resistance is 39 times more than that of conventional cemented tungsten carbide, and its toughness against impact is more than 200 J. All these data show the button has very good mechanical properties.

  6. Preparation and Corrosion Resistance of Rare Earth Conversion Coatings on AZ91 Magnesium Alloy

    Xu Yue; Chen Xiang; Lü Zushun; Li Yingjie


    The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings (short for RECCs) on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optimum processing parameters on corrosion resistance of RECCs, such as density of treating solution, temperature and time of coating formation were discussed. Protective performance of conversion coatings on magnesium alloy was evaluated by moisture/heating test, anodic polarization, etc. The results show that Ce-based RECCs under moisture/heating condition can remain intact, with high coverage and no obvious corrosion phenomenon. Corrosion potential increases and passive phenomenon occurs while current density decreases, therefore Ce-based RECCs can improve corrosion resistance of AZ91 magnesium alloy. The morphology of Ce-based RECCs prepared under optimum process through SEM observation is found to be a few particles coherent to the base coating, and the coating has no cracks and exhibits apparent corrosion resistance during corrosion courses of AZ91 magnesium alloy.

  7. A rare-earth free magnesium alloy with improved intrinsic ductility.

    Sandlöbes, S; Friák, M; Korte-Kerzel, S; Pei, Z; Neugebauer, J; Raabe, D


    Metals are the backbone of manufacturing owing to their strength and formability. Compared to polymers they have high mass density. There is, however, one exception: magnesium. It has a density of only 1.7 g/cm(3), making it the lightest structural material, 4.5 times lighter than steels, 1.7 times lighter than aluminum, and even slightly lighter than carbon fibers. Yet, the widespread use of magnesium is hampered by its intrinsic brittleness. While other metallic alloys have multiple dislocation slip systems, enabling their well-known ductility, the hexagonal lattice of magnesium offers insufficient modes of deformation, rendering it intrinsically brittle. We have developed a quantum-mechanically derived treasure map which screens solid solution combinations with electronic bonding, structure and volume descriptors for similarity to the ductile magnesium-rare earth alloys. Using this insight we synthesized a surprisingly simple, compositionally lean, low-cost and industry-compatible new alloy which is over 4 times more ductile and 40% stronger than pure magnesium. The alloy contains 1 wt.% aluminum and 0.1 wt.% calcium, two inexpensive elements which are compatible with downstream recycling constraints.

  8. Thermodynamics analysis of the rare earth metals and their alloys with indium in solid state

    Vassiliev, V.P., E-mail: [Chemical Department, Lomonossov University, Moscow 119992 (Russian Federation); Benaissa, Ablazeze [Département des Matériaux, Faculté des Sciences de l’Ingénieur, Université M’hamed Bougara, Boumerdes 35000 (Algeria); Taldrik, A.F. [Institute of Superconductivity and Solid State Physics, Academician Kurchatov 1, Moscow 123098 (Russian Federation)


    Graphical abstract: Gibbs energies of formation vs. RE atomic numbers in REIn{sub 3}. Highlights: •Set of experimental values was collected for REIn{sub 3} phases. •Thermodynamic functions of formation were calculated at 298 K and 775 K. •Experimental and calculated values were compared. -- Abstract: Nonlinear correlative analyses between thermodynamic and some physico-chemical properties of rare-earth metals (RE) and their alloys with indium are performed for the isostructural phases RE and REIn{sub 3}. The thermodynamics values (Gibbs energies of formation, enthalpies of formation, and entropies of formation at 298 K and 775 K and standard entropies) of LnIn{sub 3} phases are calculated on the basis of calorimetry and potentiometry results. The proposed correlation between physico-chemical and thermodynamic properties agrees for all the isostructural phases REX (X are others elements of the periodic table). The resulting thermodynamic data are recommended for metallurgical handbook.

  9. Cyclic Deformation Behavior of a Rare-Earth Containing Extruded Magnesium Alloy: Effect of Heat Treatment

    Mirza, F. A.; Chen, D. L.; Li, D. J.; Zeng, X. Q.


    The present study was aimed at evaluating strain-controlled cyclic deformation behavior of a rare-earth (RE) element containing Mg-10Gd-3Y-0.5Zr (GW103K) alloy in different states (as-extruded, peak-aged (T5), and solution-treated and peak-aged (T6)). The addition of RE elements led to an effective grain refinement and weak texture in the as-extruded alloy. While heat treatment resulted in a grain growth modestly in the T5 state and significantly in the T6 state, a high density of nano-sized and bamboo-leaf/plate-shaped β' (Mg7(Gd,Y)) precipitates was observed to distribute uniformly in the α-Mg matrix. The yield strength and ultimate tensile strength, as well as the maximum and minimum peak stresses during cyclic deformation in the T5 and T6 states were significantly higher than those in the as-extruded state. Unlike RE-free extruded Mg alloys, symmetrical hysteresis loops in tension and compression and cyclic stabilization were present in the GW103K alloy in different states. The fatigue life of this alloy in the three conditions, which could be well described by the Coffin-Manson law and Basquin's equation, was equivalent within the experimental scatter and was longer than that of RE-free extruded Mg alloys. This was predominantly attributed to the presence of the relatively weak texture and the suppression of twinning activities stemming from the fine grain sizes and especially RE-containing β' precipitates. Fatigue crack was observed to initiate from the specimen surface in all the three alloy states and the initiation site contained some cleavage-like facets after T6 heat treatment. Crack propagation was characterized mainly by the characteristic fatigue striations.

  10. Dynamic performance of magneto-optical Bi-substituted rare-earth iron garnet

    Shiguang Li; Changxi Yang; Enyao Zhang; Guofan Jin


    @@ The dynamic performances of magneto-optical Bi-substituted rare-earth iron garnet (BIG) under different external magnetic fields and at different frequencies are experimentally studied. The measurement data indicate that the Faraday rotation angle is almost proportional to the external magnetic field when the garnet is far less saturated, while there is good switch performance when it is saturated. The higher the working frequency is, the larger the saturation magnetic field and the phase delay of Faraday angle relative to the field. The saturation fields and the phase delays at different frequencies are measured. The dynamic performance of the BIG determines the performance of BIG-based optical devices. To get the better performance of such devices, the garnets with small dampness and large stiffness should be chosen elaborately.

  11. Palladium-rare-earth metal alloys-advanced materials for hydrogen power engineering


    Hydrogen of no less than 99. 999 % (vol. fraction) purity is a principal power media of hydrogen power engineering. A single method for the preparation of high purity hydrogen consists in its separation from vapour-gas mixtures via the selective diffusion of hydrogen through a palladium membrane. The rate of hydrogen diffusion and the strength and stability during the operation in aggressive gases are important characteristics of palladium membranes. The increase in the strength, plasticity, and hydrogen-permeability of membrane alloys can be reached by alloying palladium with the formation of solid solutions.The formation of wide ranges of palladium-rare-earth metal (REM) solid solutions is an interesting feature of palladium. Earlier, we have shown that the alloying of Pd with REM substantially increases the rate of hydrogen diffusion and markedly increases the strength of palladium on retention of the adequate plasticity.In this work, we have studied alloys of the Pd-Y and Pd-Y-Me systems. It was shown that the following conditions should be satisfied to prepare high-quality alloys exhibiting high service properties: (1)the use of high-purity components (whose purity is no less than 99.95%, mass fraction), in particular,high-purity Y prepared by vacuum distillation, and (2) holding the reached purity for the final product.For this purpose, we suggested a cycle of manufacturing operations including the preparation of a vacuumtight foil of 50 (m thick as the final stage.The hydrogen-permeability of the alloys was measured at different temperatures and hydrogen pressures. The instability of operation of binary Pd-Y alloys w alloying the composition with a Ⅷ Group metal. For example, the alloy of the optimum composition Pd-8Y-Me in the annealed state exhibits the following mechanical properties: HV= 75 kg/mm2 , σu = 58 kg/mm2 , and δ= 20%. Its hydrogen-permeability (QH2) measured as a function of the temperature exceeds that of the Pd-23Ag alloy (that is widely

  12. {sup 57}Fe Moessbauer spectroscopy applied to the study of rare-earth iron permanent magnets

    Persiano, A.I.C. [Departamento de Fisica-UFMG (Brazil)], E-mail:


    A survey of some important applications of {sup 57}Fe Moessbauer spectroscopy to the study of local magnetic and structural characteristics of the main phases in the rare-earth-transition metal (RE-TM) class of materials used in the development of the new generations of high performance permanent magnets is presented. A brief history of the hard magnets evolution in the last decades is followed by the description and interpretation of the main effects on the hyperfine interactions revealed by the Moessbauer technique. The contribution of the distinct crystallographic iron sites to the saturation magnetization of the rare-earth iron compounds is discussed in terms of the corresponding types of magnetic coupling, based mainly on the iron-iron distances, the number of iron neighbors and the respective hyperfine fields. These features are inferred from the energy of the resonant absorption by the iron sites 4e/4c/8j{sub 1}/8j{sub 2}/16k{sub 1}/16k{sub 2} in the Nd{sub 2}Fe{sub 14}B, sites 6c/9d/18f/18h in the light RE{sub 2}Fe{sub 17}N{sub 3} and 8f/8i/8j in the RE(Fe{sub 12-x}TM{sub x}) phases. The direction of the easy axis of magnetization is discussed taking into account the effects due to the interaction between the local magnetization vector and the electric field gradients. Some other characteristics such as the occupancy of the TM atoms in the 1 : 12 compounds as well as in some hybrid (Fe +TM) 2 : 17 structures are also discussed in terms of the changes in the relative subspectral areas. The effects regarding charge transfers and lattice expansions due to the incorporation of nitrogen and also of other different interstitial elements to the 2 : 17 rhombohedral structure are discussed considering the relative changes of the isomer shifts in comparison with the alterations in the parameter due exclusively to the respective volume expansions.

  13. Exchange coupling and superconductivity in light rare earth alloys and superlattices

    Deen, P P M


    The complementary techniques of X-ray magnetic resonant scattering, neutron and X-ray diffraction and SQUID magnetometry have been employed to explore rare earth superlattices and thin films. In particular, this thesis concerns the complex magnetism of Cerium, exchange coupling in Nd/Pr superlattices and the interplay between magnetism and superconductivity in Gd/La superlattices. Molecular beam epitaxy enables the growth of high quality single-crystal structures that do not occur in nature with tailor-made physical properties. Fundamental problems in condensed matter physics can therefore be addressed. Through a study of CeY and CeLu alloys, the origin of diffuse scattering and intermediate valence behaviour observed in CeHo alloys was determined. XMRS was able to probe the behaviour of Ce in various environments. A higher energy resonance, indicative of intermediate valence behaviour, is present for the Lu and Ho based alloys but not for those containing Y. Since the lattice parameters of CeLu closely match...


    L.J.Shang; A.Q.Sun; J.F.Chen; C.M.Zhang; Q.K.Cai


    A gradient coating of Fe-based alloy was manufactured with rare earths (RE) by plasma surfacing on Q235 steel substrate. The coatings were studied by using X-ray diffraction (XRD),scanning electron microscope(SEM),differential thermal analyzer (DTA ),and electron probe micro-analyzer (EPMA). The results show that the phases of the two kinds of coatings(with and without RE) both include α-Fe, Fe7C3, Fe3C, Cr2B, Fe2B and FeB. The microstructure ofF314 coating is mainly hypereutectic, the pro-phases Cr7C3 and Cr2B are loose, crassi, spiculate and contain microcracks. The brittleness of the coating is high, and the average hardness is 787 HV. When 0.8wt% RE was added into the F314 alloy, the microstructure varied from hypoeutectic to hypereutectic continuously, The hardness appears as gradient distribution with the highest value of 773 HV, meanwhile, the brittleness decreases significantly. The formation of gradient structure depends on the fallowing factors: (i) the conversion of RE. The addition of RE lowers the elements point and Fe-C eutectic temperature, thus the base metal melting acutely. (ii) the heating of plasma arc.Graded temperature results in directional solidification, thus the gradient structure forms easily. The main reasons for the hardness decrease with RE addition in the alloy are the ratio of hard phase lowering and the hardness of the hard phase decreasing.

  15. Study on Rare Earth-Containing Phases in TiAl Based Alloys Prepared by Non-Equilibrium Solidification Processing

    马学著; 沈军; 贾均


    Microstructure evolution of rare earth rich phase of rapidly-solidified (RS) TiAl based alloys was investigated. The two rapid-solidification techniques employed are melt-spinning technique (MS) and Hammer-and-Anvil technique (HA). MS ribbons and HA foils were obtained in the experiment. The results demonstrate that with the increasing of cooling rates of TiAl based alloys great changes are taken place in the microstructures of rare earth rich phase, from scattering mainly on grain boundaries of as-cast ingot to distributing homogeneously as very fine fibers or powders (nanometer grade) on the matrix. The fine paralleling second phase fibers in the HA foils are considered to be connected with γ/α2 lamellar colonies. Selected area electronic diffraction (SAED) patterns of the rare earth rich phase is in accordance with that of intermetallic AlCe.

  16. Microstructure and creep behavior of magnesium-aluminum alloys containing alkaline and rare earth additions

    Saddock, Nicholas David

    In the past few decades governmental regulation and consumer demands have lead the automotive companies towards vehicle lightweighting. Powertrain components offer significant potential for vehicle weight reductions. Recently, magnesium alloys have shown promise for use in powertrain applications where creep has been a limiting factor. These systems are Mg-Al based, with alkaline earth or rare earth additions. The solidification, microstructure, and creep behavior of a series of Mg-4 Al- 4 X:(Ca, Ce, La, and Sr) alloys and a commercially developed AXJ530 (Mg--5 Al--3 Ca--0.15 Sr) alloy (by wt%) have been investigated. The order of decreasing freezing range of the five alloys was: AX44, AXJ530, AJ44, ALa44 and ACe44. All alloys exhibited a solid solution primary alpha-Mg phase surrounded by an interdendritic region of Mg and intermetallic(s). The primary phase was composed of grains approximately an order of magnitude larger than the cellular structure. All alloys were permanent mold cast directly to creep specimens and AXJ530 specimens were provided in die-cast form. The tensile creep behavior was investigated at 175 °C for stresses ranging from 40 to 100 MPa. The order of decreasing creep resistance was: die-cast AXJ530 and permanent mold cast AXJ530, AX44, AJ44, ALa44 and ACe44. Grain size, solute concentration, and matrix precipitates were the most significant microstructural features that influenced the creep resistance. Decreases in grain size or increases in solute concentration, both Al and the ternary addition, lowered the minimum creep rate. In the Mg-Al-Ca alloys, finely distributed Al2Ca precipitates in the matrix also improved the creep resistance by a factor of ten over the same alloy with coarse precipitates. The morphology of the eutectic region was distinct between alloys but did not contribute to difference in creep behavior. Creep strain distribution for the Mg-Al-Ca alloys developed heterogeneously on the scale of the alpha-Mg grains. As

  17. Corrosion Inhibition Mechanism of Rare Earth Metal on LC4 Al Alloy with Spilt Cell Technique


    A new method of studying the corrosion inhibition mechanism of rare earth metal(REM) on LC4 Al alloy with the spilt cell technique was studied. The principle and experimental method of the spilt cell technique were analyzed. By measuring the change of net-electric current between the two electrodes caused by the change of the amount of oxygen in the solution and the addition of CeCl3, the influence of corrosive performance of CeCl3 on LC4 super-power aluminum alloy in the 0.1 mol*L-1 NaCl solution was investigated. Meanwhile, the conditional changes of pH values, CeCl3 solution, additire and time of performance were also studied. Finally, the features of electrode surface were revealed by using SEM and X-ray energy-dispersive spectrometry (EDS). By combining these with other electric chemical techniques, such as potential-time curve, polarization curve et al.

  18. Texture evolution during thermomechanical processing in rare earth free magnesium alloys

    Miller, Victoria Mayne

    The use of wrought magnesium alloys is highly desirable for a wide range of applications where low component weight is desirable due to the high specific strength and stiffness the alloys can achieve. However, the implementation of wrought magnesium has been hindered by the limited room temperature formability which typically results from deformation processing. This work identifies opportunities for texture modification during thermomechanical processing of conventional (rare earth free) magnesium alloys via a combination of experimental investigation and polycrystal plasticity simulations. During deformation, it is observed that a homogeneous distribution of coarse intermetallic particles efficiently weakens deformation texture at all strain levels, while a highly inhomogeneous particle distribution is only effective at high strains. The particle deformation effects are complemented by the addition of alkaline earth solute, which modifies the relative deformation mode activity. During recrystallization, grains with basal orientations recrystallize more readily than off-basal grains, despite similar levels of internal misorientation. Dislocation substructure investigations revealed that this is a result of enhanced nucleation in the basal grains due to the dominance of prismatic slip. This dissertation identifies avenues to enhance the potential formability of magnesium alloys during thermomechanical processing by minimizing the evolved texture strength. The following are the identified key aspects of microstructural control: -Maintaining a fine grain size, likely via Zener pinning, to favorably modify deformation mode activity and homogenize deformation. -Developing a coarse, homogeneously distributed population of coarse intermetallic particles to promote a diffuse deformation texture. -Minimizing the activity of prismatic slip to retard the recrystallization of grains with basal orientations, allowing the development of a more diffuse recrystallization texture.

  19. Microstructure and composition of rare earth-transition metal-aluminium-magnesium alloys

    Lia Maria Carlotti Zarpelon


    Full Text Available The determination of the microstructure and chemical composition of La0.7-xPr xMg0.3Al 0.3Mn0.4Co0.5 Ni3.8 (0 < x < 0.7 metal hydride alloys has been carried out using scanning electron microscopy (SEM, energy dispersive X ray analysis (EDX and X ray diffraction analysis (XRD. The substitution of La with Pr changed the grain structure from equiaxial to columnar. The relative atomic ratio of rare earth to (Al, Mn, Co, Ni in the matrix phase was 1:5 (LaNi5-type structure. Magnesium was detected only in two other phases present. A grey phase revealed 11 at.% Mg and the concentration ratios of other elements indicated the composition to be close to PrMgNi4. A dark phase was very heterogeneous in composition, attributed to the as-cast state of these alloys. The phases identified by XRD analysis in the La0.7Mg0.3Al0.3Mn0.4Co 0.5Ni3.8 alloy were: La(Ni,Co5, LaAl(Ni,Co4, La2(Ni,Co7 and AlMn(Ni,Co2. Praseodymium favors the formation of a phase with a PuNi3-type structure. Cobalt substituted Ni in the structures and yielded phases of the type: Pr(Ni,Co5 and Pr(Ni,Co3.

  20. Study on the Rare Earth Sealing Procedure of the Porous Film of Anodized 2024 Aluminum Alloy


    The rare earth sealing procedure of the porous film of anodized aluminum alloy 2024 was studied with the fieldemission scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS). The results show thatRE solution can form cerium oxide/hydroxides precipitation in the pores of the anodized coating at the beginning ofsealing. At the same time, the spherical deposits formed on the surface of the anodized coating created a barrierto the precipitation of RE solution in the pores. When the pore-structured anodizing film is covered all with thespherical deposits, RE conversion coating will form on the surface of the anodized coating. The reaction of thecoating formation was investigated by employing cyclic voltammetry. The results indicate that accelerator H2O2 actsas the source of O2 by carrying chemical reaction in course of coating formation. In the mean time, it maybe carrieselectrochemical reaction to generate alkaline condition to accelerate the coating formation. The porous structure ofthe film is beneficial to the precipitation of the cerium hydroxides film.

  1. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.


    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  2. 熔盐电解法制备稀土合金研究进展%Research progress in the preparation of rare earth alloys by molten salt electrolysis method

    郭探; 王世栋; 叶秀深; 李权; 刘海宁; 郭敏; 吴志坚


    Rare earth alloys can be prepared through the methods of melting, metallothermic reduction, and molten salt electrolysis. Compared to the former two methods, the molten salt electrolysis method has several advantages: the production cost is lower, the composition of the rare earth alloys is uniform and easy control, and the quality of the rare earth alloys is good. The rare earth alloys can be prepared easily and continuously on industrial scale. In this paper, the research progress in the molten salt electrolysis preparation of the rare earth alloys of magnesium, aluminum, iron, cobalt, nickel, and copper is reviewed by considering the rare earth alloy applications in structural, magnetic, and hydrogen storage materials. The prospects of the related research works are discussed.%熔盐电解法制备稀土合金具有成本低、成份均匀且容易控制、质量较好、易实现连续化生产等优势.本文结合稀土合金在金属结构材料、磁性材料和贮氢材料中的应用,在介绍熔盐电解的知识进展的基础上,综述了稀土分别与镁、铝、铁、钴、镍、铜等组成的合金的熔盐电解制备研究进展,并对以后的研究工作进行展望.

  3. Magnetic nanosized rare earth iron garnets R3Fe5O12: Sol-gel fabrication, characterization and reinspection

    Opuchovic, Olga; Kareiva, Aivaras; Mazeika, Kestutis; Baltrunas, Dalis


    The magnetic nanosized rare earth iron garnets (R3Fe5O12, where R=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were prepared by an aqueous sol-gel method. Herein we present, that all these garnets can be obtained by this effective synthesis method simply by changing the temperature of the final annealing. It was also demonstrated, that a different annealing temperature leads to a different particle size distribution of the final product. The SEM analysis results revealed that the smallest particles were formed in the range of 75-130 nm. The phase purity and structure of the rare earth iron garnets were estimated using XRD analysis and Mössbauer spectroscopy. Magnetic properties were determined by magnetization measurements. The relation between the particle size, composition and magnetic properties of the sol-gel derived garnets were also discussed in this study.

  4. Influence of rare earth nanoparticles and inoculants on performance and microstructure of high chromium cast iron

    HOU Yuncheng; WANG You; PAN Zhaoyi; YU Lili


    The high chromium cast irons (HCCIs) with rare earth (RE) nanoparticles or inoculants were fabricated in the casting process.The phase compositions and microstructure were analyzed by X-ray diffraction (XRD) and optical microscopy (OM),respectively.The hardness and impact toughness were tested by Rockwel-hardmeter and impacting test enginery.And then,the morphology of fracture was researched by scanning electron microscopy (SEM).The results demonstrated that the phase compositions of HCCIs with addition of RE nanoparticles or inoculants which were M7C3 carbides + α -Fe did not change obviously.However,the prime M7C3 carbides morphology had great changes with the increase of RE nanoparticles,which changed from long lath to granular or island shape.When the content of RE nanoparticles was 0.4 wt.%,the microstructure of high chromium cast iron was refined greatly.The microstructure of carbides was coarser when the addition of RE nanoparticles was higher than 0.4 wt.%.The hardness and impact toughness of HCCIs were improved by addition of RE nanoparticles or inoculants.The impact toughness of HCCIs was increased 36.4% with RE nanoparticles of 0.4 wt.%,but the hardness changed slightly.In addition,the adding of RE nanoparticles or inoculants could reduce the degree of the brittle fracture.Fracture never seemed regular,instead,containing lots of laminates and dimples with the increase of the RE nanoparticles.The results also indicated that the optimal addition amonnt of the RE nanoparticles was 0.4%,under this composition,the microstructure and mechanical property achieved the best cooperation.In addition,through the study of erosion wear rate,when adding 0.4% RE nanoparticles into the HCCIs,the erosion wear rate got the minimum 0.32×10-3 g/mm2,which could increase 51.5% compared with that without any RE nanoparticles.

  5. Quantum Magnetism Applied to the Iron-Pnictides and Rare Earth Pyrochlores

    Applegate, Ryan

    This dissertation presents computational studies of two families of magnetic materials of significant current interest. The iron pnictides are new high temperature superconductors with interesting parent compound antiferromagnetism. The rare earth pyrochlore material Yb2Ti2O7 is a candidate quantum spin ice. The magnetic and structural phases of individual iron pnictides have both many common features and material specific differences. In an attempt to unify these behaviors as instances of a larger theoretical picture, we use Monte Carlo simulations of a two-dimensional Hamiltonian with coupled Heisenberg-spin and Ising-orbital degrees of freedom. We introduce spin-space and single-ion anisotropies and study the finite temperature transitions in our model. We develop a phase diagram and propose that the interplay of spin and orbital physics in the presence of anisotropy could explain how material details affect the transitions of the pnictide materials. Nuclear magnetic resonance (NMR) can study magnetic materials via the hyperfine interaction and the coupling between the nuclear moment and the field produced by the samples local moment environment. Recent measurements suggest that Zn doped BaFe2As2 may have quantum fluctuations about the striped phase that produce a distribution of fields at As nuclear sites. The non-magnetic ion Zn replaces Fe and can be treated as an impurity which can be studied by a zero-temperature Ising Series expansion method. We propose a Heisenberg-like J1a-J 1b-J2 model which has small ferromagnetic exchanges along the b axis and strong antiferromagnetic exchanges along the a axis. In our impurity model we find that the magnetic moments are everywhere reduced by quantum fluctuations, except on the nearest neighbor site in the AFM direction. We suggest that the presented impurity model may provide an explanation for the experimental measurements. Based on a recently proposed quantum spin ice model, we use numerical linked cluster (NLC

  6. Quantification of the strengthening effect of rare earth elements during hot deformation of Mg-Gd-Y-Zr magnesium alloy

    Hamed Mirzadeh


    Full Text Available The flow stress of Mg-Gd-Y-Zr, Mg-Al-Zn, and Mg-Zn-Zr magnesium alloys during hot deformation were correlated to the Zener–Hollomon parameter through analyses based on the proposed physically-based and apparent approaches. It was demonstrated that the theoretical exponent of 5 and the lattice self-diffusion activation energy of magnesium (135 kJ/mol can be set in the hyperbolic sine law to describe the peak flow stresses. As a result, the influence of rare earth elements, gadolinium (Gd and yttrium (Y, upon the hot working behavior was readily characterized by the proposed approach, which was not possible by the conventional apparent approach. It was shown quantitatively that the rare earth addition exerts a profound effect on the hot strength and hence on the creep resistance.

  7. Rare Earth Market Review


    @@ Rare earth market continued drop tendency.There was not much transaction of didymium oxide and the alloy. Affected by reduced order of NdFeB magnetic materials and inactive dealings of didymium mischmetal,price of didymium mischmetal had dropped from RMB ¥95,000~98,000/ton to RMBY 93,000~95,000/ton currently.

  8. Effect of Rare Earth Metals, Sr, and Ti Addition on the Microstructural Characterization of A413.1 Alloy

    M. G. Mahmoud


    Full Text Available The present work was performed on A413.1 alloy containing 0.2–1.5 wt% rare earth metals (lanthanum or cerium, 0.05–0.15% Ti, and 0–0.02 wt% Sr. These elements were either added individually or combined. Thermal analysis, image analysis, and electron probe microanalysis were the main techniques employed in the present study. The results show that the use of the depression in the eutectic temperature as a function of alloy modification cannot be applied in the case when the alloy is treated with rare earth metals. Increasing the concentration of RE increases the solidification zone especially in Sr-modified alloys leading to poor feeding ability. This observation is more prominent in the case of Ce addition. Depending upon the amount of added Ti, two RE based intermetallics can be formed: (i a white phase, mainly platelet-like (approximately 2.5 μm thick, that is rich in RE, Si, Cu, and Al and (ii a second phase made up of mainly grey sludge particles (star-like branching in different directions. The grey phase is rich in Ti with some RE (almost 20% of that in the white phase with traces of Si and Cu. There is a strong interaction between RE and Sr leading to a reduction in the efficiency of Sr as a eutectic Si modifier causing particle demodification.

  9. 用稀土合金对铸造铝合金精炼和变质处理的研究%A New Approach to Refining and Modifying Cast Aluminum Alloys with Rare Earth Alloys

    唐多光; 毛协民


    The effects of rare earth (RE) alloys on the refining and modifying of cast aluminum alloys were investigated. Compared to other substances in common use, rare earth alloys maintain the refining and modifying effects of the aluminum alloys for a longer time. RE alloys can also reduce environmental pollution in the melting process. These effects of RE alloys make them become a superior choice for the applications in aluminum foundry.

  10. Effect of Rare Earths on Electronic Structure of (110) Twin Martensite Boundary for Ni2MnGa Alloy


    The doping effect of rare earth elements (Tb and Sm) on the electronic structure of (110) martensitic twin boundary in Ni2MnGa alloys was investigated by using ab initio method within the DFT and the supercell implementation. The calculated results show that the atomic relaxation lowers the boundary energy and the segregation energy. Sm seems easier to segregate to the boundary and has a greater doping effect compared with Tb due to its lower segregation energy and bigger bonder order with neighboring atoms. Tb makes a greater contribution to the magnetic properties of the twin boundary than Sm.

  11. Activity and Stability of Rare Earth-Based Hydride Alloys as Catalysts of Hydrogen Absorption-Oxidation Reactions

    Ying Taokai(应桃开); Gao Xueping(高学平); Hu Weikang(胡伟康); Noréus Dag


    Rare earth-based AB5-type hydrogen storage alloys as catalysts of hydrogen-diffusion electrodes for hydrogen absorption and oxidation reactions in alkaline fuel cells were investigated. It is demonstrated that the meta-hydride hydrogen-diffusion electrodes could be charged by hydrogen gas and electrochemically discharged at the same time to retain a stable oxidation potential for a long period. The catalytic activities and stability are almost comparable with a Pt catalyst on the active carbon. Further improvement of performances is expected via reduction of catalyst size into nanometers.

  12. Effect of combinative addition of strontium and rare earth elements on corrosion resistance of AZ91D magnesium alloy

    NIU Jie-xin; CHEN Qiu-rong; XU Nai-xin; WEI Zhong-ling


    The influence of strontium(Sr) and rare earth(RE) elements on the corrosion behavior of AZ91D magnesium alloy was investigated by conventional corrosion testing and electrochemical measurements in 3.5% NaCI solution. After comparing the mass loss and hydrogen evolution of the samples, the microstruetures of the alloys and the morphologies of their corrosion product films were characterized by electron probe microanalysis-energy dispersive spectrometry(EPMA-EDS) and Auger electron spectroscopy(AES). Compared with individual addition of Sr or RE to AZ91D, the combinative addition of 0.5% Sr and 1% RE to AZ91D successfully decreases the corrosion rate further, which can be attributed to the depression of micro-galvanic couples, as well as the formation of more protective film due to aluminum enrichment. The combinative addition of strontium and rare earth elements to AZ91D magnesium alloy appears to he a promising approach to increase its corrosion resistance.

  13. In Situ Scanning Electron Microscopy Observation of Tensile Deformation in Sn-Ag-Cu Alloys Containing Rare-Earth Elements

    Xiao, Wei Min; Shi, Yao Wu; Lei, Yong Ping; Xia, Zhi Dong; Guo, Fu


    The effects of rare-earth (RE) element additions on the tensile deformation mechanism of the Sn-3.8Ag-0.7Cu solder alloy have been investigated. The results show that adding RE elements can remarkably improve the tensile strength and elongation of the Sn-3.8Ag-0.7Cu alloy. The increase in the mechanical properties are attributed to the constraints of microcrack growth and grain boundary sliding in the eutectic phase as well as the relaxation of stress concentration in the β-Sn phase due to the addition of the RE elements. It is considered that the RE elements strengthen the eutectic phase and increase the deformation resistance of this alloy.

  14. Calculation of crystal-field parameters for rare-earth noble metal alloys

    Steinbeck, L. [MPG Research Group `Electron Systems`, Department of Physics, University of Technology, Mommsenstr. 13, D-01062, Dresden (Germany); Richter, M. [MPG Research Group `Electron Systems`, Department of Physics, University of Technology, Mommsenstr. 13, D-01062, Dresden (Germany); Eschrig, H. [MPG Research Group `Electron Systems`, Department of Physics, University of Technology, Mommsenstr. 13, D-01062, Dresden (Germany); Nitzsche, U. [MPG Research Group `Electron Systems`, Department of Physics, University of Technology, Mommsenstr. 13, D-01062, Dresden (Germany)


    The crystal-field (CF) parameters for 4f electrons of a series of rare-earth impurities in Ag and Au have been evaluated from first-principles density functional calculations of the charge distribution which are based on an optimized LCAO scheme. The localized 4f states are treated as `open core shell`. By including the self-interaction correction for the 4f states, artificial constraints on the 4f charge density employed in earlier density functional CF calculations are avoided. The calculated parameters are compared with recent neutron scattering data. ((orig.)).

  15. Calculation of crystal-field parameters for rare-earth noble metal alloys

    Steinbeck, L.; Richter, M.; Eschrig, H.; Nitzsche, U.


    The crystal-field (CF) parameters for 4f electrons of a series of rare earth impurities in Ag and Au have been evaluated from first-principles density functional calculations of the charge distribution which are based on an optimized LCAO scheme. The localized 4f states are treated as 'open core shell'. By including the self-interaction correction for the 4f states, artificial constraints on the 4f charge density employed in earlier density functional CF calculations are avoided. The calculated parameters are compared with recent neutron scattering data.


    朱龙章; 陈宇飞; 俞江萍


    Zinc-Nickel electrodepositing process and corrosion resistance ofZinc-Nickel obtained in a chloride bath with or without rare earth compounds are investigated.The experimental results show that the process of Zinc-Nickel alloy belongs to "anomalous codeposition" and the nickel content (mass percent) of Zinc-Nickel alloy coating is about 13%.When a small amount of rare earth compounds are added to the bath,the cathodic polarization of the electrodepositing process is increased,the alloy coatings gained from the bath become more close in structure and more fine in crystal and the corrosion resistance is also improved.

  17. Theory of Temperature Dependence of the Magnetization in Rare-Earth-Transition-Metal Alloys

    Szpunar, B.; Lindgård, Per-Anker


    It is shown that the temperature dependence of the magnetic moments and Curie and ferrimagnetic compensation temperatures for Gdl-xTx (T = Co, Ni, and Fe) and Y1-xCox can be accounted for by a simple model assuming a RKKY interaction between the rare-earth moments and the transition-metal pseudo-spin......1-xCox durch ein einfaches Model1 erklärt werden können, das eine RKKY-Wechsel-wirkung zwischen den Momenten der Seltenen Erden und des Pseudo-Spins des Übergangsmetalls annimmt. Die Wechselwirkung wird durch ein effektives Legierungsmedium übermittelt, das mit der CPA-Theorie und elliptischen...

  18. Microstructure of Steel 5Cr21Mn9Ni4N Alloyed by Rare Earth


    The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth (RE) amount were studied. Mechanical properties of 5Cr21Mn9Ni4N steels withont RE addition and with RE added by 0. 2 % in mass percent were tested respectively. The results indicate that the solid solution amount of RE is about 10-6 -10-5 order of magnitude in 5Cr21Mn9Ni4N steel. Dendrite of as-cast condition is refined obviously and dimension of interstitial phase is shortened when RE is added by 0. 10%-0. 20%. But the microstructure will be coarser if surplus RE is added. Precipitated phase under finished product state distributes evenly in nearly same size with RE added by 0.2% which leads to a largely improved high temperature mechanical property.

  19. Effect of Rare Earth Cerium on Yield Strength Anisotropy of Al-Li Alloy Sheet and Its Theoretical Prediction

    赵志龙; 刘林; 陈铮


    The variation of yield strength along rolling direction, transverse direction and 45° to transverse direction of 2090 Al-Li alloy and 2090+Ce alloy sheet containing rare earth cerium was comparatively investigated. The difference of deformation texture in these two alloy sheets was analyzed by means of X-ray orientation distribution function (ODF). The results show that cerium has the effects of enhancing the Brass and S rolling texture components and reducing the recrystallized texture components of Cube and Goss. This is the reason that the anisotropic degree of yield strength in 2090+Ce sheet is higher than that of 2090 alloy sheet. The prediction of yield strength along various orientations in two alloy sheets was done based on Taylor/Bishop-Hill model, and the strengthening effect of grain boundary was evaluated using Hall-Petch relationship. A modified plastic inclusion model was proposed using the concept of grain-orientation factor and T1 phase orientation factor by fitting with tensile test results.

  20. Effect of isothermal heat treatment on semi-solid microstructure of AZ91D magnesium alloy containing rare earth Gd

    Yong Hu


    Full Text Available The AZ91D magnesium alloy containing rare earth Gd was prepared in this study, and the effect of semi-solid isothermal heat treatment on the microstructure of the alloy was investigated to obtain an optimum semi-solid structure. Results show that Gd can refine the microstructure of AZ91D magnesium alloy, and the optimum semi-solid AZ91D microstructure can be achieved by adding 1.5wt.% Gd. After treated at 585 °C for 30 min, the well distributed rose-shaped and near-spherical semi-solid microstructures of AZ91D+1.5wt.%Gd alloy can be obtained. The liquid phase of the semi-solid alloy consists of three components, namely, the molten pool, the “entrapped liquid” pool and the liner liquid film which separates two neighbor particles. The solid phase is composed of two phases, the primary α-Mg particles and the α-Mg phase formed in the second stage of solidification. With the increase of holding time, melting which causes the decrease of the primary α-Mg particle size is the dominant mechanism in the initial stage while coalescence and Ostwald ripening tend to be the principles later.

  1. Partial Remelting of Thixotropic Magnesium-Rare Earth Alloy from Near Non- Equilibrium- Liquidus Casting


    After the investigation on partial remelting of thixotropic magnesium serial alloys (ZK60) by near non-equilibrium liquidus casting (NNLC), the primary solid grains of ZK60-2Ca alloy spheroidized notably during partial remelting processing, however, coarsening and polygonization as occurred holding time prolonged. The refining and globularity of the thixotropic alloys are promoted after further alloyed by Y, RE, Nd and/or Ag, and the results vary with those addition. The remelting structure of ZK60-2Ca-1Y alloy is finer than its base alloy. And the effect of RE, especially Ag, on the refinement of microstructure is notable, but Nd does nothing on it. There is little impact of remelting temperature fluctuation on partial remelted microstructure as holding time in general. On the contrary, it is more sensitive at longer holding time. The quality thixotropic silver-contained alloy can be achieved by remelted partially at 600 ℃ for 10 min.

  2. Wear-Resistance Performance of ZA-27 Alloys Reinforced by Rare Earth Compounds


    The morphology of ZA-27 alloy reinforced by RE compounds and its wear-resistance were studied. It is found that some nodular second phases appear due to the addition of Si and RE, which can disperse in grain boundaries or between dendrite crystals so that the alloy has been refined. Energy spectrum analysis of scanning electron microscope shows that the second phases are complex compounds containing RE, Al, Zn and Si. The micro-hardness test indicates that micro-hardness values of the compounds are higher than those of the matrix. The wear-resistance of ZA-27 alloy reinforced by RE compounds is 4 times as high as that of ZA-27 alloy and also higher than that of ZA-27 alloy containing Si phase. The impact toughness of the alloy containing RE and Si is higher than that of the alloy containing Si.

  3. (BRI) Direct and Inverse Design Optimization of Magnetic Alloys with Minimized Use of Rare Earth Elements


    of the desired magnetic properties of the alloys. Sensitivity analysis of the variation of concentrations of each of the alloying elements revealed ...capable of exploring yet unexplored domains of the design space. Sensitivity analysis also revealed that certain alloying elements have negligible...Principal Investigator during the previous decade and applied to design optimization of H-type steels , Ni DISTRIBUTION A: Distribution approved for


    Gewang Shuai


    Full Text Available The microstructural evolution of Cu-based alloys during aging was studied using a quantitative metallographic method. Samples were cut from ingots of Cu-0.8wt%Cr and Cu-0.8wt%Cr-RE alloys. These were solution treated at 1000 ºC for 1.5h and subsequently quenched in water, then separately aged at 480 ºC for different durations. The microstructures were observed by optical microscope, and the characteristic geometric parameters of precipitated Cr phase, including volume fraction VV, face density NA, mean diameter and roundness, were measured. These data provided more details about the process of aging. The results showed that precipitation of Cr phase occurred in the form of particles during aging. Rare earth elements promoted the precipitation of Cr phase and dispersed Cr particles. The phenomenon of overaging came earlier in Cu-Cr-RE than in Cu-Cr. In the present work, the optimal aging time at 480 ºC was 2 hrs for the Cu-0.8wt%Cr-RE alloy and 3 hours for the Cu-0.8wt%Cr alloy.

  5. Eutectic modification in a low-chromium white cast iron by a mixture of titanium, rare earths, and bismuth: Part II. effect on the wear behavior

    Bedolla-Jacuinde, A.; Aguilar, S. L.; Maldonado, C.


    In this work, we studied the wear behavior of a low-Cr white cast iron (WCI) modified with ferrotitanium-rare earths-bismuth (Fe-Ti-RE-Bi) up to 2%. These additions modified the eutectic carbide structure of the alloy from continuous ledeburite into a blocky, less interconnected carbide network. The modified structure was wear tested under pure sliding conditions against a hardened M2 steel counter-face using a load of 250 N. It was observed that wear resistance increased as the modifier admixture increased. The modified structure had smaller more isolated carbides than the WCI with no Fe-Ti-RE-Bi additions. It was observed that large carbides fracture during sliding, which destabilizes the structure and causes degradation in the wear behavior. A transition from abrasive to oxidative wear after 20 km sliding occurred for all alloys. In addition, the modified alloys exhibited higher values of hardness and fracture toughness. These results are discussed in terms of the modified eutectic carbide microstructure.

  6. Applying ellipsometry to studying the effect of two kinds of rare earth metal salts on anodizing aluminum alloy

    H00G Quan; QIAN Ying; LI Lingjie; ZHANG Shengtao


    The effects of rare earth metal salts (REMs), cerium(Ⅳ) salt and lanthanum (Ⅲ) salt, on the property of anodized coating of LD10 aluminum alloy are studied by corrosion tests including neutral salt spray test and copper accelerated acetic acid immersion test, polarization curves measurement, energy dispersion analyzer of X-Ray(EDAX) analysis, and in situ ellipsometry. The results show that the addition of either of the two REMs in anodizing solution hardly changes the composition of an anodized coating, while increases the thickness of barrier part and reduces the porosity of porous part, which contributed to the improvement of the corrosion resistance of the anodized coating. The results also demonstrate that the effect of cerium salt was better than that of lanthanum salt.

  7. Probing the nanoscale structure of the catalytically active overlayer on Pt alloys with rare earths

    Pedersen, Anders Filsøe; Ulrikkeholm, Elisabeth Therese; Escribano, Maria Escudero


    PtxY and PtxGd exhibit exceptionally high activity for oxygen reduction, both in the polycrystalline form and the nanoparticulate form. In order to understand the origin of the enhanced activity of these alloys, we have investigated thin films of these alloys on bulk Pt(111) crystals, i.e. Y/Pt(1...

  8. Ion Probe Study of Silicate Inclusions from Colomera (IIE) Iron Meteorite:the Rare Earth Element Perspective

    HSU Weibiao


    Coupled with a petrographical study, I carried out an ion probe study of rare earth element microdistributions in mineral phases of silicate inclusions from the Colomera IIE iron meteorite. Most mineral grains have homogeneous REEs, but show considerable inter-grain variations by a factor of 2 to 100. The whole rock REE abundances for Colomera,estimated by combining REE data with modal abundances, are relatively LREE-enriched with REEs of ~10'CI, which suggest that Colomera silicates were highly differentiated and might represent a low degree partial melt (~10%) of a chondritic source. REE geochemistry of Colomera silicate inclusions points to an origin that involves differentiation,dynamic mixing, remelting, reduction, recrystallization, and subsequent rapid cooling near the surface of a planetary body.

  9. Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Mg-Li Alloys


    A series of α-based Mg-Li-Al-Zn-xRE alloys were prepared. These alloys have low density ranging from 1.5 to 1.7 g·cm-3 and high strength properties. The influence of RE element on the microstructure and the mechanical properties of these alloys were studied. The results indicate that the addition of RE (La, Pr, Ce) leads to the formation of rod-shaped intermetallic compound Al2Zn2La distributed in the matrix. Al2Zn2La induces reduction of the laminar spacing and causes refinement of the microstructure. Therefore, this compound improves the strength of alloys at a high temperature.

  10. Hydrogen Absorption Thermodynamic Properties of Rare Earth Based Hydrogen Storage Alloy in Benzene

    蔡官明; 陈长聘; 安越; 徐国华; 陈立新; 王启东


    The hydriding/dehydriding thermodynamic properties of the slurry system formed by suspending La-rich mischmetal nickel hydrogen storage alloy (MlNi5) in Benzene (C6H6) were investigated. The pressure-composition isotherms for both the alloy powder and the slurry suspended with MlNi5 were measured at several temperatures(10, 20, 30, 40 ℃). The standard enthalpy of formation ΔH° and standard entropy of formation ΔS° for the alloy powder with and without benzene were determined respectively. The experimental results show that the values of ΔH° and ΔS° for the hydriding reaction of hydrogen storage alloy (MlNi5) of the slurry system and the gas-solid system are all very close.

  11. Derivative thermo analysis of the Al-Si cast alloy with addition of rare earths metals

    M. Krupiński


    Full Text Available In this paper the dependence between chemical composition, structure and cooling rate of Al–Si aluminium cast alloy was investigated. For studying of the structure changes the thermo-analysis was carried out, using the UMSA (Universal Metallurgical Simulator and Analyzer device. For structure investigation optical and electron scanning microscopy was used, phase and chemical composition of the Al cast alloy also using qualitative point-wise EDS microanalysis.

  12. Analysis of the Deformation Behavior of Magnesium-Rare Earth Alloys Mg-2 pct Mn-1 pct Rare Earth and Mg-5 pct Y-4 pct Rare Earth by In Situ Energy-Dispersive X-ray Synchrotron Diffraction and Elasto-Plastic Self-Consistent Modeling

    Lentz, Martin; Klaus, Manuela; Coelho, Rodrigo S.; Schaefer, Nobert; Schmack, Florian; Reimers, Walter; Clausen, Bjørn


    The deformation behavior of the Mg-RE alloys ME21 and WE54 was investigated. Although both alloys contain rare earth elements, which alter and weaken the texture, the flow curves of the alloys deviate significantly, especially in uniaxial compression test. Apart from the higher strength of the WE54 alloy, the compression flow curve does not exhibit the typical sigmoidal shape, which is associated with tension twinning. However, optical microscopy, X-ray texture measurements, and EBSD analysis reveal the activity of tension twinning. The combination of in situ energy-dispersive X-ray synchrotron diffraction and EPSC modeling was used to analyze these differences. The investigation reveals that twin propagation is decelerated in the WE54 alloy, which requires a change of the twinning scheme from the `finite initial fraction' to the `continuity' assumption. Furthermore, an enhanced activity of the pyramidal slip system was observed in case of the WE54 alloy.

  13. Passive behavior of magnesium alloys (Mg-Zr) containing rare-earth elements in alkaline media

    Pinto, R. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Ferreira, M.G.S. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal); CICECO, Universidade de Aveiro (Portugal); Carmezim, M.J. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Instituto Politecnico de Setubal, ESTSetubal, DEM (Portugal); Montemor, M.F., E-mail: mfmontemor@ist.utl.p [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal)


    The passive behavior of magnesium alloys ZK31, EZ33 and WE54 was studied in alkaline media (NaOH - pH 13) in the presence and absence of chloride ions. The electrochemical properties were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and capacitance measurements. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed for the study of the chemical composition and surface morphology of the surface films, respectively. The electrochemical impedance results revealed that the film formed on the surface of the three alloys is characterized by an increasing resistance, which stabilized with time. In the absence of chloride the film resistance was identical for all the three alloys. However, in the presence of chloride, the resistance of the film formed on the EZ33 alloy dropped nearly one order of magnitude comparatively to the other alloys. Generally, in the presence of chloride there was a decrease of the conductive character of the film. The films are homogeneous and, according to the XPS results, the outer layer seemed mainly composed of Mg(OH){sub 2} and the internal layer composed of MgO, independently of the presence of chloride. The AFM study revealed that the presence of chloride affected film morphology, namely nano-crystallites dimensions and aggregates size that increased.

  14. Rare Earth Market Review


    @@ Oversupply of rare earths led to the significant price drop of rare earth mineral products and separated products in Chinese domestic market. To stabilize the price, prevent waste of resources, further improve regulation capability on domestic rare earth market and rare earth price and maintain sustaining and healthy development of rare earth industry, partial rare earth producers in Baotou and Jiangxi province projected to cease the production for one month.

  15. Hf-Co and Zr-Co alloys for rare-earth-free permanent magnets.

    Balamurugan, B; Das, B; Zhang, W Y; Skomski, R; Sellmyer, D J


    The structural and magnetic properties of nanostructured Co-rich transition-metal alloys, Co(100-x)TMx (TM = Hf, Zr and 10 ≤ x ≤ 18), were investigated. The alloys were prepared under non-equilibrium conditions using cluster-deposition and/or melt-spinning methods. The high-anisotropy HfCo7 and Zr2Co11 structures were formed for a rather broad composition region as compared to the equilibrium bulk phase diagrams, and exhibit high Curie temperatures of above 750 K. The composition, crystal structure, particle size, and easy-axis distribution were precisely controlled to achieve a substantial coercivity and magnetization in the nanostructured alloys. This translates into high energy products in the range of about 4.3-12.6 MGOe, which are comparable to those of alnico.

  16. Method for treating rare earth-transition metal scrap

    Schmidt, Frederick A.; Peterson, David T.; Wheelock, John T.; Jones, Lawrence L.


    Rare earth-transition metal (e.g., iron) scrap (e.g., Nd-Fe-B scrap) is flux (slag) remelted to reduce tramp non-metallic impurities, such as oxygen and nitrogen, and metallic impurities, such as Li, Na, Al, etc., picked up by the scrap from previous fabrication operations. The tramp impurities are reduced to concentrations acceptable for reuse of the treated alloy in the manufacture of end-use articles, such as permanent magnets. The scrap is electroslag or inductoslag melted using a prefused, rare earth fluoride-bearing flux of CaF.sub.2, CaCl.sub.2 or mixtures thereof or the slag resulting from practice of the thermite reduction process to make a rare earth-iron alloy.

  17. Hot deformation behavior of rare earth magnesium alloy without pre-homogenization treatment


    The behavior and structure evolvement of as-cast Mg-Gd-Y-Nd-Zr magnesium alloy during the hot deformation process were discussed. The flow stress behavior of magnesium alloy over the strain rate range of 0.002-1 s-1 and the temperature range of 573-723 K was researched on Gleeble-1500D hot simulator under the maximum deformation degree of 60%. The experimental results show that the relationship between stress and strain is obviously affected by the strain rate and deformation temperature. The important softening mechanisms are eutectic melting and discontinuous dynamic recrystallization (DDRX) during deformation. The fragments of eutectie melting along the boundaries can turn round so as to take effect of the slippage between grains. The flow stress of Mg-7Gd-5Y-1.2Nd-Zr magnesium alloy during high temperature deformation can be represented by a Zener-Hollomon parameter in the hyperbolic Arrhenius-type equation. The strain coefficient n and deformation activation energy Q are evaluated by linear regression analysis. A, α and n in the analytical expressions of σ are fitted to be 2.401 93× 1015, 0.017 3 MPa-1 and 3.218 19,respectively. The hot deformation activation energy of alloy during hot deformation is 234.950 58 kJ/mol. The results also show that the structure of primitive microstructure has an effect on the plastic deformation.

  18. The role of intermetallic phases in the corrosion of magnesium-rare earth alloys

    Silva Campos, Maria del Rosario


    A new concept to develop a RE based Mg alloy with improved corrosion resistance was followed in the current work. Based on subsequent characterisation steps to eliminate less suitable RE elements the best microstructure for improved corrosion resistance was identified. At first, the corrosion properties of selected RE elements were determined. Based on these results RE elements that have a potential to enhance the corrosion resistance of Mg-RE alloys were selected. Two aspects of RE elements were important for the selection: the electrochemical properties and the solid solubility in Mg. If the solubility limit of RE elements in the Mg matrix is exceeded, they form intermetallic phases with Mg. By performing galvanic coupling measurements the compatibility between Mg matrix and intermetallic phases were estimated. At that point three binary Mg-RE alloys systems remained (Mg-Ce, Mg-La, and Mg-Gd). To evaluate the influence of composition (amount of intermetallic phases) on the corrosion behaviour, four concentrations were cast with 1, 5, 10 and 15 wt. % of RE. Ce and La have a lower solid solubility in Mg matrix generating higher volume fraction of the secondary phases, thus higher dissolution rates in the binary Mg-RE alloys. While Gd with higher solid solubility shows a different behaviour. Additions of up to 10 wt. % Gd resulted in similar behaviour compared to 1 wt. % Gd addition. The most promising results were obtained for the Mg-Gd system with 10 wt. % Gd. Thus, the microstructure of this alloy was further modified by heat treatments to understand the influence of microstructural changes on corrosion behaviour. A ternary element was used to attempt further optimisation of the corrosion performance. Additions of Al, Zn, Ga and Y did not show any improvement in the corrosion resistance of Mg10Gd. This is due to increasing volume fractions of critical more noble phases and the microstructure dominated by eutectic phase formation. Thus galvanic effects became much

  19. The influence of d- and f-states on structure formation - amorphous alloys containing rare earths as model systems

    Stiehler, Martin; Pleul, Michael; Haeussler, Peter [Chemnitz University of Technology, 09126 Chemnitz (Germany)


    Amorphous phases as precursors of the crystalline state are interesting for investigating fundamental structure forming processes and the related evolution of electronic transport. During the last years we were able to show that many different classes of alloys organize themselves under the influence of a resonance-like interaction between the global subsystems of the electrons and the static structure. Especially for binary Al-TM alloys TM: the transition metals of the 4th period (Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu) we reported recently on an electronic influence on phase stability driven by hybridization effects between the Al-p- and the TM-d-states, showing an interesting systematics depending on the number of unoccupied TM-d-states reflected in different properties. Currently we are about to extend those investigations to systems with transition metals of the 5th and 6th period. Embedded in this class of elements are the so-called Rare Earth metals (Sc, Y, La, and the Lanthanoids). These elements exhibit very similar chemical properties although some of them (the Lanthanoids) contain f-electrons. This provides the possibility of studying the influence of localized magnetic moments (f-states) on structure formation. In this contribution we report on results concerning the static structure, the electrical resistivity and the Hall effect of the binary systems Al-Y and Al-Ce.

  20. The influence of d- and f-states on structure formation - amorphous alloys containing Rare Earths as model systems

    Stiehler, Martin; Pleul, Michael; Haeussler, Peter [Chemnitz University of Technology, 09126 Chemnitz (Germany)


    Amorphous phases as precursors of the crystalline state are interesting for investigating fundamental structure forming processes and the related evolution of electronic transport. During the last years we were able to show that many different classes of alloys organize themselves under the influence of a resonance interaction between the global subsystems of the electrons and the static structure. Especially for binary Al-TM alloys (TM: the transition metals of the 4th period Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu) we reported recently on an electronic influence on phase stability driven by hybridization effects between the Al-p- and the TM-d-states, showing an interesting systematics depending on the number of unoccupied TM-d-states reflected in different properties. Currently we are about to extend the investigations to systems with transition metals of the 5th and 6th period. Embedded in this class of elements are the so-called Rare Earth metals (Sc, Y, La, and the Lanthanoids). These elements exhibit very similar chemical properties although some of them (the Lanthanoids) contain f-electrons. This provides the possibility of studying the influence of magnetic influences, provided by the localized f-states, on structure formation. In this contribution we report on preliminary results concerning the static structure, the electrical resistivity and the Hall effect of the binary systems Al-Y and Al-Ce.

  1. Microstructure, corrosion resistance and cytocompatibility of Mg-5Y-4Rare Earth-0.5Zr (WE54) alloy

    Smola, Bohumil, E-mail: [Charles University Prague, Faculty of Mathematics and Physics, Ke Karlovu 5, 121 16 Praha 2 (Czech Republic); Joska, Ludek [Institute of Chemical Technology Prague, Faculty of Chemical Technology, Technicka 5, 166 28 Praha 6 (Czech Republic); Brezina, Vitezslav [University of South Bohemia, Institute of Physical Biology, Zamek 136, 373 33 Nove Hrady (Czech Republic); Stulikova, Ivana [Charles University Prague, Faculty of Mathematics and Physics, Ke Karlovu 5, 121 16 Praha 2 (Czech Republic); Hnilica, Frantisek [Czech Technical University in Prague, Faculty of Mechanical Engineering, Karlovo namesti 13, 121 35 Praha 2 (Czech Republic)


    Conventionally cast Mg-5Y-4Rare Earth-0.5Zr alloy (WE54) was solution treated (525 Degree-Sign C/8 h - T4) and one part subsequently aged (200 Degree-Sign C/16 h - T6). Powder from the cast WE54 alloy prepared by gas atomizing was consolidated by extrusion at 250 Degree-Sign C or 400 Degree-Sign C. Dense triangular arrangement of prismatic plates of transient D0{sub 19} and C-base centered orthorhombic phases precipitated in the {alpha}-Mg matrix during the T6 treatment. Both alloys prepared by powder metallurgy exhibit similar microstructure consisting of {approx} 4-6 {mu}m {alpha}-Mg matrix fibers surrounded by particles of the equilibrium Mg{sub 5}(Y, Nd) phase and of oxides. Open circuit potential and polarization resistance in the isotonic saline (9 g/l NaCl/H{sub 2}O) were monitored for 24 h. The corrosion rate of the T4 and T6 treated alloys was about 80 times lower than that of commercial Mg. Both alloys prepared by powder metallurgy exhibited approximately 8 times higher corrosion resistance than commercial Mg. The human MG-63 osteoblast-like cells spreading and division in the extracts (0.28 g in 28 ml of EMEM) of all 4 alloys were monitored by cinemicrography for 24 h. The MG-63 cells proliferate without cytotoxicity in all extracts. - Highlights: Black-Right-Pointing-Pointer T6 treated WE54 alloy exhibit dense triangular arrangement of {beta} Double-Prime and {beta} Prime phase prismatic plates. Black-Right-Pointing-Pointer Microstructure of PM prepared WE54 alloy consists of {alpha}-Mg phase cells surrounded by {beta} phase particles. Black-Right-Pointing-Pointer PM produced WE54 corroded 10 times faster in physiological solution thanT4 and T6 treated WE54. Black-Right-Pointing-Pointer MG63 cell spreading in EMEM extracts of PM prepared WE54 is comparable to that in control EMEM. Black-Right-Pointing-Pointer Cell mitosis is enhanced in PM WE54 extracts compared to the control and extracts of T4 and T6 WE54.

  2. Extraction of transplutionium and rare-earth elements, molybdenum and iron with zirconium salt of dibutyl phosphoric acid

    Zilberman, B. Ya.; Fedorov, Yu. S.; Shmidt, O. V.; Goletsky, N. D.; Sukhareva, S. Yu.; Puzikov, E. A.; Suglobov, D. N.; Mashirov, L. G.; Choppin, G. R.


    Zirconium salt of dibutyl phosphoric acid (ZS-HDBP) dissolved in dilute tributyl phosphate (TBP) is proposed as a solvent for separation of transplutonium and rare-earth elements (TPE, RE), including yttrium, from high-level waste in the presence of molybdenum and iron. The optimum HDBP:Zr ratio is 9 for RE and TPE extraction and is 12.5 for Mo. IR spectra indicate formation of Zr(DBP)4(HDBP)4 complex as a base of solvation. HNO3 depresses RE and TPE extraction, while Mo extraction is characterised by a minimum at 2.5 mol/L HNO3. Presence of TBP in the solvent, independently of the used diluent, leads to reduction of the distribution coefficients, but ZS-HDBP extraction capacity for the above elements is increased, as well as solubility of their solvates. Two types of complexes M(DBP)3 and MNO3(DBP)2 are formed at RE and TPE extraction by ZS-HDBP in dilute TBP. Molybdenum extraction is based both on cation exchange and on Mo solvation with HDBP as a neutral ligand. Iron extraction is formally similar to that of Mo, being influenced by the latter if both metals are present in the solution.

  3. Processing of rare earth concentrates

    Pamela Alex; R. C. Hubli; A.K. Suri


    The paper describes process details for extraction of rare earths from an intermediate grade concentrate of Madhya Pradesh region in India and a South African slag. The xenotime concentrate obtained from the former place was an intermediate grade (47%) rare earth phosphate containing both monazite and xenotime. The South African slag was a low-grade waste product typically containing only 4% of rare earths. The rare earth resource concentrates have been treated individually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Both types of materials have been processed and greater than 98% solubilization of metal values has been achieved in the intermediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thoroughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths from thorium effectively. Other impurities such as uranium and iron have been removed by precipitation of rare earths by oxalic acid. It has been possible to recover >95% yttrium along with other rare earth oxides.

  4. Rare Earth Resolution

    Mei Xinyu


    BEFORE the early 1970s, China had no rare earth exports, and the world rare earth market was dominated by the United States, Europe and Japan. In the 1970s, China began to enter the world rare earth market and its share has picked up sharply in the following decades. Today, having the monopoly over global rare earth production, China must improve the benefits from rare earth production, not only from producing individual rare earth products, but also from mastering the intensive processing of rare earth products.

  5. Alloys of Pt and Rare Earths for the Oxygen Electroreduction Reaction

    Malacrida, Paolo

    of potential cycling, Y oxidizes due to the dealloying process which is observed in-situ. The adsorbed species can be also probed and correlated to the electrochemical potential. Near the open circuit potential (OCP) conditions the oxygenated species consist, to a good extent, of non-hydrated OH, similar......This thesis presents the development and characterization of a new class of Pt alloys for catalyzing the Oxygen Reduction Reaction (ORR), in perspective of a future substitution of traditional Pt-based catalysts at the cathode of Polymer Electrolyte Membrane Fuel Cells (PEMFCs). Focused......-of-the-art polycrystalline Pt. They maintain at least 90% of this activity after accelerated stability tests (10 000 cycles between 0.6 and 1.0 V vs. the Reversible Hydrogen Electrode (RHE) in 0.1 M HClO4 electrolyte). A combination of AR-XPS and ISS measurements allowed to elucidate the active surface phase and structure...

  6. A metallurgical approach toward alloying in rare earth permanen magnet systems

    Branagan, Daniel J. [Iowa State Univ., Ames, IA (United States)


    The approach was developed to allow microstructural enhancement and control during solidification and processing. Compound additions of Group IVA, VA, or VIA transition metals (TM) and carbon were added to Nd2Fe14B (2-14-1). Transition metal carbides formed in IVA (TiC, ZrC, HfC) and Group VA (VC, NbC, TaC) systems, but not in the VIA system. The alloying ability of each TM carbide was graded using phase stability, liquid and equilibrium solid solubility, and high temperature carbide stability. Ti with C additions was chosen as the best system. The practically zero equilibrium solid solubility means that the Ti and C additions will ultimately form TiC after heat treatment which allows the development of a composite microstructure consisting of the 2-14-1 phase and TiC. Thus, the excellent intrinsic magnetic properties of the 2-14-1 phase remain unaltered and the extrinsic properties relating to the microstructure are enhanced due to the TiC stabilized microstructure which is much more resistant to grain growth. When Ti + C are dissolved in the liquid melt or solid phases, such as the glass or 2-14-1 phase, the intrinsic properties are changed; favorable changes include increased glass forming ability, reduced optimum cooling rate, increased optimum energy product, and enhanced nucleation kinetics of crystallization.

  7. Effect of rare earth cerium and impurity tin on the hot ductility of a Cr-Mo low alloy steel

    宋申华; 徐野威; 陈贤淼; 姜雪


    The specimens of 1Cr-0.5Mo low alloy steel, undoped, Sn-doped and Ce+Sn-doped, were austenitized at 1300ºCand then cooled down to different temperatures in the range of 700–1050ºC, followed by tensile tests with the aid of a Gleeble machine. The reduction of area (RA) obtained from the test was employed to evaluate the hot ductility of the steel. The testedspecimens were char-acterized using different techniques. Minor Sn could considerably reduce the RA values of the steel in the whole temperature range, and the hot ductility curve could be widened and deepened. Nevertheless, minor Ce could improve the hot ductility of the Ce+Sn-doped steel by fully suppressing the Sn-induced hot ductility deterioration. FEGSTEM microanalysis showed that the Sn or Ce and Sn atoms segregated to austenite grain boundaries in the Sn-doped or Ce+Sn doped specimens. The detrimental effect of Sn on the hot ductility could be attributed mainly to the segregation of Sn as it could decrease the grain boundary cohesion andin turn enhancedthe grain boundary sliding and cracking. However, this detrimental effect of Sn could be counteracted by the segregation of Ce which could increase the grain boundary cohesion and in turn restrainedthe grain boundary sliding and cracking. Accordingly, a minor addition of rare earth Ce could be an effective method of suppressing the detrimental effectof impurity elements on the hot ductility of a Cr-Mo low alloy steel.

  8. Co-based alloys design based on first-principles calculations: Influence of transition metal and rare-earth alloying element on stacking fault energy

    Achmad, Tria Laksana; Fu, Wenxiang; Chen, Hao; Zhang, Chi; Yang, Zhi-Gang


    The main idea of alloy design is to reduce costs and time required by the traditional (trial and error) method, then finding a new way to develop the efficiency of the alloy design is necessary. In this study, we proposed a new approach to the design of Co-based alloys. It is based on the concept that lowering the ratio of stable and unstable stacking fault energy (SFE) could bring a significant increase in the tendency of partial dislocation accumulation and FCC to HCP phase transformation then enhance mechanical properties. Through the advance development of the computing techniques, first-principles density-functional-theory (DFT) calculations are capable of providing highly accurate structural modeling at the atomic scale without any experimental data. The first-principles calculated results show that the addition of some transition metal (Cr, Mo, W, Re, Os, Ir) and rare-earth (Sc, Y, La, Sm) alloying elements would decrease both stable and unstable SFE of pure Co. The dominant deformation mechanism of binary Co-4.5 at.% X (X = alloying element) is extended partial dislocation. Our study reveals Re, W, Mo and La as the most promising alloying additions for the Co-based alloys design with superior performances. Furthermore, the underlying mechanisms for the SFE reduction can be explained regarding the electronic structure.

  9. Rare earth elements: end use and recyclability

    Goonan, Thomas G.


    Rare earth elements are used in mature markets (such as catalysts, glassmaking, lighting, and metallurgy), which account for 59 percent of the total worldwide consumption of rare earth elements, and in newer, high-growth markets (such as battery alloys, ceramics, and permanent magnets), which account for 41 percent of the total worldwide consumption of rare earth elements. In mature market segments, lanthanum and cerium constitute about 80 percent of rare earth elements used, and in new market segments, dysprosium, neodymium, and praseodymium account for about 85 percent of rare earth elements used. Regardless of the end use, rare earth elements are not recycled in large quantities, but could be if recycling became mandated or very high prices of rare earth elements made recycling feasible.

  10. Effect of Ce-rich rare earth on microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb magnesium alloy

    You Zhiyong


    Full Text Available To improve the comprehensive mechanical properties of Mg-10Zn-5Al-0.1Sb magnesium alloy, different amount of Ce-rich rare earth (RE was added to the alloy, and the effect of RE addition on the microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb alloy was investigated by means of Brinell hardness measurement, scanning electron microscopy (SEM, energy dispersive spectroscope (EDS and X-ray diffraction (XRD. The results show that an appropriate amount of Ce-rich rare earth addition can make the Al4Ce phase particles and CeSb phase disperse more evenly in the alloy. These phases refine the alloy抯 matrix and make the secondary phases [t-Mg32(Al,Zn49 phase and f-Al2Mg5Zn2 phase] finer and more dispersive, therefore significantly improve the mechanical properties of the Mg-10Zn-5Al-0.1Sb alloy. When the RE addition is 1.0 wt.%, the tensile strengths of the alloy both at room temperature and 150 篊 reach the maximum values while the impact toughness is slightly lower than that of the matrix alloy. The hardness increases with the increase of RE addition.

  11. Variation of Aging Precipitates and Mechanical Strength of Al-Cu-Li Alloys Caused by Small Addition of Rare Earth Elements

    Ma, Yun-long; Li, Jin-feng


    The effect of small rare earth (RE) addition of 0.11%Ce, 0.2%Er and 0.082%Sc on aging precipitates and mechanical strength of an Al-(3.3-4.2)Cu-1.2Li-X alloy were investigated. It is found that Cu-rich residual particles containing RE element exist in the solutionized alloy, which leads to a decrease of dissolved Cu concentration in the solutionized matrix. Like RE-free alloy, the main aging precipitate types in RE-containing alloy are T1 (Al2CuLi) and θ' (Al2Cu), but their fraction is decreased. The strength of the corresponding alloys is therefore lowered by the small RE addition. Combined with the analysis of some reported references, it is proposed that the effect of small RE addition on Al-Cu-Li alloy strength is also associated with the Cu and Li concentrations and their ratio.

  12. Ultra high sensitivity, room temperature magneto-optic field sensor made of ferromagnetic bismuth rare-earth iron garnet thick films

    Wu, Dong Ho; Garzarella, Anthony; Fratello, Vince


    The ferrimagnetic bismuth rare-earth iron garnet (BiGdLu)3 (FeGa)5 O12 thick film has a specific Faraday rotation θS of 0.09 °/mm at 1550 nm and excellent transparency at infrared wavelengths. Using the thick film we recently have demonstrated a magneto-optic (MO) field sensor with a sensitivity of about 10-14 T/ Hz 1/2 , comparable with SQUID. The sensor is made of all dielectric materials including the bismuth rare-earth iron garnet and optical fibers, and is operated at room temperature without any cooling requirement. The MO field sensor is capable to measure a magnetic field over a very large dynamic range (from a very weak field to a very high magnetic field exceeding several hundred Tesla) and over a very wide frequency range, which may be from DC to a few hundred GHz. However, presently, our MO sensor's frequency range is limited from DC to 2 GHz. We think that this limited frequency range is due to the presence of magnetic domains in the bismuth rare-earth iron garnet film. In this presentation we will report our experimental results obtained from this MO field sensor as well as the effect of magnetic domains.

  13. Use of rare earth oxides and iron oxides as soil erosion tracers in water erosion experiments at hillslope scale

    Guzmán, G.; Cañasveras, J. C.; Barrón, V.; Boulal, H.; Gómez, H.; Conde, E.; Fernández, M.; Gómez, J. A.


    The characteristics of the ideal soil erosion have been defined by several authors, for example by Zhang et al. (2001). Despite intensive research on erosion tracers in the last decades there is not a single tracer fulfilling all these characteristics. That is why research on different soil erosion tracers remains as an active field. Two desirable characteristics in erosion tracers are that they should be relatively inexpensive (to purchase and analyze) and that they should be determined with high accuracy in soil or sediment. The availability of multiple tracers is another of the key requirements. In this communication we present our preliminary results on the use of two different sets of erosion tracers. One set are iron oxides with different magnetic and optical properties (Fe3O4, α-Fe2O3 and FeOOH) analyzed by NIRS and magnetic susceptibility measurements. The other set consists of five rare earth oxides (La2O3, Pr6O11, Nd2O3, Sm2O3 and Gd2O3) analyzed using inductively coupled plasma mass spectrometry (ICP-MS). These two groups were studied under controlled and natural conditions, through several water erosion experiments, in field plots with different soil management, crops and scale. In one experiment these tracers were used to determine the source of sediment within sprinkle irrigated fields planted with cotton on shoulders. For this purpose, rainfall simulations were performed under controlled conditions at two scales, one with a portable rainfall simulator at small scale (0.81m2) and with the sprinkler irrigation system in the whole cotton field (2450 m2). Furrows were tagged with both groups of tracers, keeping shoulders untagged (where cotton was planted). Soil samples before and after the rainfall simulations were collected as well as sediment samples. In another experiment four olive orchard plots (330 m2) with different soil managements (cover crop and conventional tillage) were also tagged with the two groups of tracers. Soil samples were taken at

  14. Examination of Plasma Nitriding Microstructure with Addition of Rare Earths



    Medium-carbon alloy steel was plasma nitrided with rare earths La,Ce and Nd into the nitriding chamber respectively.The nitriding layer microstructures with and without rare earths were compared using optical microscope,normal SEM and high resolution SEM,as well as TEM.It was found that the extent of the influence on plasma nitriding varies with different contents of rare earth.The effect of plasma nitriding is benefit from adding of Ce or Nd.The formation of hard and brittle phase Fe2-3N can be prevented and the butterfly-like structure can be improved by adding Ce or Nd.However,pure La may prevent the diffusion of nitrogen and the formation of iron nitride,and reduce the depth of diffusion layer.

  15. Rare earth elements, S and Sr isotopes and origin of barite from Bahariya Oasis, Egypt: Implication for the origin of host iron ores

    Baioumy, Hassan M.


    Based on their occurrences and relation to the host iron ores, barites are classified into: (1) fragmented barite occurs as pebble to sand-size white to yellowish white barite along the unconformity between the Bahariya Formation and iron ores, (2) interstitial barite is present as pockets and lenses of large and pure crystals inside the iron ores interstitial barite inside the iron ores, and (3) disseminated barite occurs at the top of the iron ores of relatively large crystals of barite embedded in hematite and goethite matrix. In the current study, these barites have been analyzed for their rare earth elements (REE) as well as strontium and sulfur isotopes to assess their source and origin as well as the origin of host iron ores. Barite samples from the three types are characterized by low ΣREE contents ranging between 12 and 21 ppm. Disseminated barite shows relatively lower ΣREE contents (12 ppm) compared to the fragmented (19 ppm) and interstitial (21 ppm) barites. This is probably due to the relatively higher Fe2O3 in the disseminated barite that might dilute its ΣREE content. Chondrite-normalized REE patterns for the three barite mineralizations exhibit enrichment of light rare earth elements (LREE) relative to heavy rare earth elements (HREE) as shown by the high (La/Yb)N ratios that range between 14 and 45 as well as pronounced negative Ce anomalies varying between 0.03 and 0.18. The 87Sr/86Sr ratios in the analyzed samples vary between 0.707422 and 0.712237. These 87Sr/86Sr values are higher than the 87Sr/86Sr ratios of the seawater at the time of barite formation (Middle Eocene with 87Sr/86Sr ratios of 0.70773 to 0.70778) suggesting a contribution of hydrothermal fluid of high Sr isotope ratios. The δ34S values in the analyzed barites range between 14.39‰ and 18.92‰. The lower δ34S ratios in the studied barites compared with those of the seawater at the time of barite formation (Middle Eocene with δ34S ratios of 20-22‰) is attributed to a



    Full Text Available Results of development and certification of reference materials of composition of heat resisting nickel alloy with the certified values of content of detrimental impurities (Zn, Cd, Pb, Tl, Bi, In, Ag, Sb, Ga, Ge, As, Se, Sn, Te, Mn, Cu, rare earth elements (Pr, Nd, Dy, Gd, Ho, Er, Nb, Sc, Y, La, Ce, and also other impurities (P, B, Fe, Si, V, Ru, Zr, Hf, Ca, Mg are given. Developed CRMs are used for calibration of optical emission spectrometers, mass-spectrometers with glow discharge and laser sampling and others.

  17. The effect of rare earth elements on the kinetics of the isothermal coarsening of the globular solid phase in semisolid AZ91 alloy produced via SIMA process

    Nami, B. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Shabestari, S.G., E-mail: [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Miresmaeili, S.M. [Department of Mechanical Engineering, Shahid Radjaei University, Lavizan, Tehran (Iran, Islamic Republic of); Razavi, H.; Mirdamadi, Sh. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of)


    In the present study, the effects of rare earth (RE) elements on the microstructure and coarsening kinetics of the solid globular particle in the semisolid slurry of AZ91 magnesium alloy have been studied at 570 {sup o}C and 580 {sup o}C. The results showed that the coarsening kinetics of the solid globular particles in semisolid slurry of AZ91 alloy satisfies the Ostwald ripening theory. It was shown that the coarsening rate of the solid particles decreases by adding RE elements into AZ91 alloy, specially at 580 {sup o}C, which results in the smaller particles size. It was attributed to the solid-liquid interfacial energy reduction due to the addition of RE elements.

  18. Influence of the rare earth concentration on the crystallization process of Fe-Dy-B amorphous alloys. Study of Fe74Dy6B20 and Fe70Dy10B20 alloys

    Ravach, G.; Machizaud, F.; Teillet, J.; LeBreton, J. M.; Fnidiki, A.


    The crystallization behaviour of Fe74 Dy6 B20 and Fe70 Dy10 B20 amorphous alloys was carefully investigated by differential scanning calorimetry, Mössbauer spectrometry and x-ray diffraction up to 800 °C. Calorimetric studies were performed in limited temperature ranges that were progressively extended. For Fe74 Dy6 B20 , after partial crystallization into the tetragonal Fe3 B compound, the remaining amorphous part segregates into two amorphous `phases', respectively enriched and impoverished in dysprosium. Tetragonal Fe3 B further transforms into orthorhombic Fe3 B. Metastable Dy3 Fe62 B14 compound then forms from the Dy-impoverished amorphous fraction, and subsequent crystallization of the Dy1 + icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> Fe4 B4 phase occurs in the Dy-enriched fraction. Finally, Dy3 Fe62 B14 decomposes into bcc iron, Dy1 + icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> Fe4 B4 and iron borides. The nature of the first crystallization product suggests the existence of local environments of t-Fe3 B type for this Dy concentration. The crystallization process of Fe70 Dy10 B20 strongly differs from that of Fe74 Dy6 B20 . Segregation phenomena occur in the amorphous state prior to any crystallization. If the nature of the first crystallization product is assumed to be correlated with short-range order in the amorphous state, our results suggest that the local environments differ from those of Fe74 Dy6 B20 , as they probably involve dysprosium atoms. This behaviour would agree with a previous Mössbauer study performed on the as-quenched amorphous alloys, providing evidence for a structural modification of the iron environments in the rare earth concentration range 8-9 at.%.

  19. Influences of rare earth element Ce-doping and melt-spinning on microstructure and magnetostriction of Fe{sub 83}Ga{sub 17} alloy

    Yao, Zhanquan, E-mail: [School of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018 (China); Tian, Xiao, E-mail: [Key Laboratory for Physics and Chemistry of Functional Materials, School of Physics and Electronic Information, Inner Mongolia Normal University, Hohhot 010022 (China); Jiang, Liping; Hao, Hongbo; Zhang, Guangrui; Wu, Shuangxia; Zhao, Zengqi [Baotou Research Institute of Rare Earths, Baotou 014030 (China); Gerile, Naren [Key Laboratory for Physics and Chemistry of Functional Materials, School of Physics and Electronic Information, Inner Mongolia Normal University, Hohhot 010022 (China)


    Highlights: • The CeGa{sub 2} phase existing in the Fe{sub 83}Ga{sub 17}Ce{sub 0.8} alloy is found for the first time. • The (100) orientation of alloy become stronger after Ce doping into the Fe-Ga alloy. • The melt-spinning leads to the formation of asymmetrical DO{sub 3} phase. • The enhanced magnetostriction is credited with new phase and preferred orientation. • The Ce-doping and melt-spinning are beneficial to the improvement of magnetostriction. - Abstract: In order to improve magnetostriction of the polycrystalline Fe-Ga alloy, the rare earth element Ce was firstly doped into Fe{sub 83}Ga{sub 17} and the melt-spinning method was subsequently applied. The as-cast Fe{sub 83}Ga{sub 17} and Ce-doped Fe{sub 83}Ga{sub 17} alloys were prepared by arc melting. Then the as-cast Ce-doped Fe{sub 83}Ga{sub 17} alloy was melt-spun by the melt-spinning technique. The microstructures and magnetostrictions of all these three alloys were investigated by X-ray diffractometer (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), differential scanning calorimeter (DSC) and magnetostriction measurements. The results indicated that the CeGa{sub 2} phase and asymmetrical DO{sub 3} phase are formed caused by Ce-doping and melt-spinning, respectively. The magnetostrictions of three alloys are ranked in sequence the melt-spun Fe{sub 83}Ga{sub 17}Ce{sub 0.8} alloy > as-cast Fe{sub 83}Ga{sub 17}Ce{sub 0.8} alloy > as-cast Fe{sub 83}Ga{sub 17} alloy. The enhanced magnetostriction is attributed to the fact that the formation of new phases and the preferred orientation along (100) direction.

  20. Rare Earth Market Review


    @@ July 20~31 Rare earth market still went downward, which was mainly led by sluggish demand for didymium products. Weak demand by domestic NdFeB market was attributed to continuous price falling of didymium mischmetal.

  1. CISRI Competes for Light Rare Earth in North China


    <正>In the light rare earth market of north China,REHT,the largest rare earth enterprise in the world,has to face a bitter rival in competition.As 3 SOEs(CHINALCO,Minmetals and CNMC)are vying for the medium and heavy rare earth market of South China,a smaller SOE,i.e.,China Iron & Steel Research

  2. Corrosion and mechanical properties of AM50 magnesium alloy after being modified by 1 wt.% rare earth element gadolinium

    杨淼; 刘耀辉; 刘家安; 宋雨来


    In order to improve the corrosion and mechanical properties of AM50 magnesium alloy, 1 wt.% Gd was used to modify the AM50 magnesium alloy. The microstructure, corrosion and mechanical properties were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrochemical and mechanical stretch methods. The results indicated that β-Mg17Al12 phase decreased and Al2Gd3 and Al0.4GdMn1.6 phase existed after Gd addition. Because of the Gd addition, the grain of AM50 magnesium alloy was refined significantly, which improved the tensile strength of AM50 magnesium al-loy. The decreasing ofβ phase improved the corrosion resistance of the magnesium alloy. The fracture mechanism of the Gd modified AM50 magnesium alloy was quasi-cleavage fracture. The corrosion residual strength (CRS) of AM50 magnesium alloy was im-proved after 1 wt.% Gd addition.

  3. The fractionation and geochemical characteristics of rare earth elements measured in ambient size-resolved PM in an integrated iron and steelmaking industry zone.

    Dai, Qili; Li, Liwei; Yang, Jiamei; Liu, Baoshuang; Bi, Xiaohui; Wu, Jianhui; Zhang, YuFen; Yao, Lin; Feng, Yinchang


    Improved understanding of the fractionation and geochemical characteristic of rare earth elements (REEs) from steel plant emissions is important due to the unclear atmospheric signature of these elements and their adverse impact on human health and the environment. In this study, ambient particulate matter of different sizes was collected from one site in an integrated iron and steelmaking industrial zone (HG) and one urban background site with no direct industrial emissions (ZWY) during a 1-year sampling campaign in China. The total concentrations of REEs for TSP, PM10, and PM2.5 were 27.248, 14.989, 3.542 ng/m(3) in HG and 6.326, 5.274, 1.731 ng/m(3), respectively, in ZWY, which revealed the local influence of the steelmaking activities to the air quality. With respect to ZWY, the REEs in HG site are obviously fractionated in the coarser fraction, and LREEs account for more than 80 % of the total REE burden in all of the samples. Additionally, the REEs in HG and ZWY show a homogeneous trend with successively increased LREE/HREE ratios from the coarse particles to the fine particles. In our samples, La, Ce, Nd, and Sm are the most enriched rare earth elements, especially in the HG site. Moreover, ternary diagrams of LaCeSm indicate that the REEs in HG are potentially contributed by steelworks, carrier vehicles, coal combustion, and road dust re-suspension.

  4. Effect of Stoichiometry on Properties of Rare-Earth-Based Hydrogen Storage Alloy for Nickel-Metal Hydride Secondary Battery


    Effect of stoichiometry on microstructures, electrochemical properties and PCT characteristics of the alloys Ml(Ni0.71Co0.15-Al0.06Mn0.08)x (Ml=Lanthanum-rich Michmetal, x=4.6~5.2) have been investigated. The lattice constants a, c, and cellvolumes of non-stoichiometric alloys are bigger than those of the stoichiometric alloy. With the increasing stoichiometry x,the value of a decreases, and the value of c and cell volume increases except for those of the stoichiometric alloy; the plateaupressure of PCT curve, discharge capacity and cycling stability all increase. The alloy with x=5.2 shows the highest dischargecapacity and the best cycling stability among the studied alloys.

  5. Direct Spectrophotometric Determination of the Total Amount of Light Rare Earths with Arsenazo-DBS as a Chelator

    Yuan Fuzhen


      A direct spectrophotometric method for the determination of the total light rare earths has been developed. In this method, arsenazo-DBS is used as a chelating agent with light rare earth elements in strong acidic medium (0.04-0.48 mol l-1 of acidity). The concentrations of total rare earths in 0-15 μg /(25 ml) range can be determined accurately by this method. An absorption maximum was observed at 630 nm at which a molar absorptivity of 1.14x105 l mol-1 cm-1 was determined. The method offers high selectivity and good sensitivity towards light rare earths and features simplicity and rapidity in operation. It has been applied to the determination of light rare earths in cast iron and Ni-Fe alloys.

  6. Adsorption properties of ultradispersed powders of aluminum alloys with rare-earth metals, before and after water treatment

    Ryabina, A. V.; Shevchenko, V. G.; Eselevich, D. A.


    Adsorption of nitrogen on Al-3% La, Al-1.5% Sc, and Al-3% Ce powders before and after processing with water in the relative pressure range p/p s = 10˜3 to 0.999 is experimentally studied at a temperature of 78 K. It is shown that the interaction between ultradispersed powder and water depends on the properties of the original powder, including the original content and composition of the oxide-hydroxide phases in the surface layers of metal particles, and the length and conditions of storage. Results confirming that processing powders containing rare-earth metals with water at room temperature leads to the formation of new phases and affects their morphology are presented. It is shown that the nanopores formed between crystallites on the surface of the particles during oxidation with water and subsequent thermal dehydration play an important role in the properties of powders processed with water. The specific surface and the porosity of powders are calculated.

  7. Large magnetic anisotropy predicted for rare-earth-free F e16 -xC oxN2 alloys

    Zhao, Xin; Wang, Cai-Zhuang; Yao, Yongxin; Ho, Kai-Ming


    Structures and magnetic properties of F e16 -xC oxN2 are studied using adaptive genetic algorithm and first-principles calculations. We show that substituting Fe with Co in F e16N2 with a Co/Fe ratio ≤1 can greatly improve the magnetic anisotropy of the material. The magnetocrystalline anisotropy energy from first-principles calculations reaches 3.18 MJ / m3 (245.6 μeV per metal atom) for F e12C o4N2 , much larger than that of F e16N2 , and is one of the largest among the reported rare-earth-free magnets. From our systematic crystal structure searches, we show that there is a structure transition from tetragonal F e16N2 to cubic C o16N2 in F e16 -xC oxN2 as the Co concentration increases, which can be well explained by electron counting analysis. Different magnetic properties between the Fe-rich (x ≤8 ) and Co-rich (x >8 ) F e16 -xC oxN2 is closely related to the structural transition.

  8. Regional framework and geology of iron oxide-apatite-rare earth element and iron oxide-copper-gold deposits of the Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri

    Day, Warren C.; Slack, John F.; Ayuso, Robert A.; Seeger, Cheryl M.


    This paper provides an overview on the genesis of Mesoproterozoic igneous rocks and associated iron oxide ± apatite (IOA) ± rare earth element, iron oxide-copper-gold (IOCG), and iron-rich sedimentary deposits in the St. Francois Mountains terrane of southeast Missouri, USA. The St. Francois Mountains terrane lies along the southeastern margin of Laurentia as part of the eastern granite-rhyolite province. The province formed during two major pulses of igneous activity: (1) an older early Mesoproterozoic (ca. 1.50–1.44 Ga) episode of volcanism and granite plutonism, and (2) a younger middle Mesoproterozoic (ca. 1.33–1.30 Ga) episode of bimodal gabbro and granite plutonism. The volcanic rocks are predominantly high-silica rhyolite pyroclastic flows, volcanogenic breccias, and associated volcanogenic sediments with lesser amounts of basaltic to andesitic volcanic and associated subvolcanic intrusive rocks. The iron oxide deposits are all hosted in the early Mesoproterozoic volcanic and volcaniclastic sequences. Previous studies have characterized the St. Francois Mountains terrane as a classic, A-type within-plate granitic terrane. However, our new whole-rock geochemical data indicate that the felsic volcanic rocks are effusive derivatives from multicomponent source types, having compositional similarities to A-type within-plate granites as well as to S- and I-type granites generated in an arc setting. In addition, the volcanic-hosted IOA and IOCG deposits occur within bimodal volcanic sequences, some of which have volcanic arc geochemical affinities, suggesting an extensional tectonic setting during volcanism prior to emplacement of the ore-forming systems.The Missouri iron orebodies are magmatic-related hydrothermal deposits that, when considered in aggregate, display a vertical zonation from high-temperature, magmatic ± hydrothermal IOA deposits emplaced at moderate depths (~1–2 km), to magnetite-dominant IOA veins and IOCG deposits emplaced at shallow

  9. Distribution, evolution and the effects of rare earths Ce and Y on the mechanical properties of ZK60 alloys

    Anru Wu; Changqing Xia; Jiewen Wang


    Eight kinds of Mg-RE alloys were prepared. The distribution, evolution, and effects of RE Ce and Y in the investigated alloys were studied by examining the mechanical properties of Mg alloys using X-ray diffraction and scan electron analysis, and by TEM observation. The results show that among the investigated alloys, ZK60-1.5%Ce and ZK60-1.0%Y possessed the optimal mechanical properties. Ce and Y were distributed on the grain boundary during casting. After extrusion and T5 (150℃/0-24 h) heattreatment, Ce and Y were distributed along the extrusion direction and they existed in compound form for both as-casting and asextrusion specimens. The mechanical properties of the investigated alloys were better than those of ZK60 because of the solid solution strengthening of RE and the dispersion strengthening of Mg-RE or Mg-Zn-RE compounds.

  10. Rare (Earth Elements [score

    Camilo Méndez


    Full Text Available Rare (Earth Elements is a cycle of works for solo piano. The cycle was inspired by James Dillon’s Book of Elements (Vol. I-V. The complete cycle will consist of 14 pieces; one for each selected rare (earth element. The chosen elements are Neodymium, Erbium, Tellurium, Hafnium, Tantalum, Technetium, Indium, Dysprosium, Lanthanium, Cerium, Europium, Terbium, Yttrium and Darmstadtium. These elements were selected due to their special atomic properties that in many cases make them extremely valuable for the development of new technologies, and also because of their scarcity. To date, only 4 works have been completed Yttrium, Technetium, Indium and Tellurium.

  11. Influence of rare earth additions on the oxidation resistance of chromia forming alloys; Influencia da adicao de terras raras sobre a resistencia a oxidacao de ligas formadoras de cromia

    Pillis, Marina Fuser


    The addition of rare earths to alloys, either in elemental form or as surface coatings reduces the oxidation rate of chromia forming alloys. The rare earths either act as nucleation sites for surface oxides or get incorporates into the surface oxide and diffuse to oxide grain boundaries. If the latter occurs, a change in the defect structure close to the grain boundaries, probably takes place. In this manner, the rare earths inhibits the movement of chromium ions to the oxide/gas interface. The influence of rare earth additions to AISI 316, AISI 316L and Ni-20 Cr on their oxidation behavior has been studied., AISI 316+Ce, AISI 316+Y, Ni-20 Cr and Ni-20 Cr-2 Al-1 Ce were prepared by melting and AISI 316L, AISI 316L+Ce O{sub 2} and AISI 316L+Y{sub 2} O{sub 3} by powder compaction. The effect of superficial deposits of rare earth oxides was also studied. The alloys were coated with rare earth oxides by high temperature conversion of the respective rare earth nitrates. Isothermal oxidation tests were carried out at 900-1100 deg C and the cyclic oxidation tests consisted of 6 cycles of 2 hours each at 900 deg C, followed by cooling to room temperature. All the tests were carried out in air. Oxidation behavior was evaluated gravimetrically. Scanning electron microscopy was used to study surface morphology. Energy dispersive analysis and X-ray diffraction techniques were used to identify oxide constituents. Overall, it has been observed that with the addition of rare earths, oxidation resistance increases by decreasing oxidation rates and increasing oxide adhesion. Addition of rare earths to AISI 316 prepared by melting resulted in rapid formation of a chromium rich oxide layered near the metal/oxide interface which reduced overall oxidation rate. The addition of Ce O{sub 2} to AISI 316L was found to improve oxidation behavior after 10 hours at 1100 deg C and also inhibit the formation of volatile Cr O{sub 3}. The isothermal oxidation behavior of rare earth oxide covered

  12. Effect of Rare Earth on Microstructure of Vacuum Melting Ni-Based Self-Fluxing Alloy Coatings

    宣天鹏; 闵丹


    The Ni-based self-fluxing alloy coating containing RE was acquired by the technique of vacuum melting on the hypoeutectoid steel (Fe-0.45%C) matrix. By X-ray diffraction, SEM and EDX, the microstructure and phase structure of section of coating and the microstructure near the interface between coating and matrix were investigated, and the effect of RE on microstructure of coating was also discussed. The results show that the microstructure of the NiCrBSi alloy coating is composed of Ni-based solid solution and a lot of massive, globular and needle secondary phases CrB, Ni3B, Cr7C3, Cr23C6 among the solid solution. The metallurgical binding between steel matrix and coating is realized. RE makes needle phase of alloy coating vanish. New phases of NiB and Cr6.5Ni2.5Si are precipitated from alloy coating, and secondary phases of alloy coating are sphericized. Consequently, RE also hinders the diffusion of Ni, Cr and Si atoms from coating to matrix and Fe atoms from matrix to coating, holds back the dilution of Fe for NiCrBSi alloy coating, and assures the chemical composition of the alloy coating.

  13. Temperature and magnetic field dependence of rare -earthiron exchange resonance mode in a magnetic oxide studied with femtosecond magneto-optical Kerr effect

    Deb, Marwan; Molho, Pierre; Barbara, Bernard; Bigot, Jean-Yves


    In magnetic materials, the exchange is the strongest quantum interaction due to the Pauli exclusion principle. For that reason it can induce high-frequency modes fexch of the magnetization precession. In this work we investigate these modes over a wide range of temperatures (50 -300 K ) and magnetic fields up to 10 T in a bismuth-doped garnet with perpendicular magnetic anisotropy by performing femtosecond magneto-optical pump-probe experiments. Near the compensation temperature TM the divergence of 1 /fexch(T ) allows identifying unambiguously fexch with the rare-earthiron exchange mode. In addition, at low temperature fexch is independent of the field as usually observed. In contrast, we find that near TM,fexch decreases linearly with an increasing magnetic field. This behavior is explained in the context of the ferromagnetic resonance theory by including the perturbation term linear in the external applied field Hext.

  14. The f-spin physics of rare-earth iron pnictides: influence of d-electron antiferromagnetic order on heavy fermion phase diagram

    Zhu, Jian-xin [Los Alamos National Laboratory; Dai, Jianhui [ZHEJIANG UNIV; Si, Qimiao [RICE UNIV


    Some of the high {Tc} iron pnictides contain rare-earth elements, raising the question of how the existence and tunability of a d-electron antiferromagnetic order influences the heavy fermion behavior of the f-moments. With CeOFeP and CeOFeAs in mind as prototypes, we derive an extended Anderson lattice model appropriate for these quaternary systems. We show that the Kondo screening of the f-moments are efficiently suppressed by the d-electron ordering. We also argue that, inside the d-electron ordered state (as in CeOFeAs), the f-moments provide a rare realization of a quantum frustrated magnet with competing J{sub 1}-J{sub 2}-J{sub 3} interactions in an effective square lattice. Implications ofr the heavy fermion physics in broader contexts are also discussed.

  15. Magnetic rare earth superlattices

    Majkrzak, C.F.; Kwo, J.; Hong, M.;


    Advances in molecular beam epitaxy deposition techniques have recently made it possible to grow, an atomic plane at a time, single crystalline superlattices composed of alternating layers of a magnetic rare earth, such as Gd, Dy, Ho, or Er, and metallic Y, which has an identical chemical structure...

  16. High temperature oxidation resistance of rare earth chromite coated Fe-20Cr and Fe-20Cr-4Al alloys

    Marina Fuser Pillis


    Full Text Available Doped lanthanum chromite has been used in solid oxide fuel cell (SOFC interconnects. The high costs involved in obtaining dense lanthanum chromite have increased efforts to find suitable metallic materials for interconnects. In this context, the oxidation behavior of lanthanum chromite coated Fe-20Cr and Fe-20Cr-4Al alloys at SOFC operation temperature was studied. Isothermal oxidation tests were carried out at 1000 °C for 20, 50 and 200 hours. Cyclic oxidation tests were also carried out and each oxidation cycle consisted of 7 hours at 1000/°C followed by cooling to room temperature. The oxidation measurements and the results of SEM/EDS as well as XRD analyses indicated that lanthanum chromite coated Fe-20Cr and Fe-20Cr-4Al alloys were significantly more resistant to oxidation compared with the uncoated alloys.

  17. Effect of Rare-Earth (La, Ce, and Y) Additions on the Microstructure and Mechanical Behavior of Sn-3.9Ag-0.7Cu Solder Alloy

    Dudek, M. A.; Chawla, N.


    In this article, we report on the microstructure and mechanical properties of Ce- and Y-containing Sn-3.9Ag-0.7Cu solders. The microstructures of both as-processed solder and solder joints containing rare-earth (RE) elements (up to 0.5 wt pct) are more refined compared to conventional Sn-3.9Ag-0.7Cu, with decreases in secondary Sn dendrite size and spacing and a thinner Cu6Sn5 intermetallic layer at the Cu/solder interface. These results agree well with similar observations seen in La-containing solders reported previously. The monotonic shear behavior of reflowed Sn-3.9Ag-0.7Cu- X(Ce, Y)/Cu lap shear joints was studied as well as the creep behavior at 368 K (95 °C). The data were compared with results obtained for Sn-3.9Ag-0.7Cu and Sn-3.9Ag-0.7Cu- XLa alloys. All RE-containing alloys exhibited creep behavior similar to Sn-3.9Ag-0.7Cu. Alloys with Ce additions exhibited a small decrease in ultimate shear strength but higher elongations compared with Sn-Ag-Cu. Similar observations were seen in La-containing solders. The influence of the RE-containing intermetallics (CeSn3 and YSn3) that form in these alloys on the microstructural refinement, solidification behavior, and mechanical performance of these novel materials is discussed.

  18. Mechanism of Effects of Rare Earths on Microstructure and Properties at Elevated Temperatures of AZ91 Magnesium Alloy

    Zhang Guoying; Zhang Hui; Gao Ming; Wei Dan


    By using real-space recursion method, the energetics of the undoped and Al and/or RE atoms doped 7(1450) symmetric tilt grain boundaries (GBs) in AZ91 alloys were investigated. Similar calculations were performed on undoped and doped bulk α Mg for comparison. The results showed that Al atoms segregated at GBs in AZ91 alloys. When RE atoms were added, they also segregated at GBs, and their segregation is stronger than Al atoms′. Therefore, RE atoms retard the segregation of Al atoms. Calculations of interaction energy indicated that Al atoms repelled each other, and could form ordered phase with host Mg atoms. On the contrary to the case of Al, RE atoms attracted each other, they could not form ordered phase with Mg, but could form clusters. Between RE and Al, there existed attractive interaction, and this attractive interaction was the origin of Al11RE3 precipitation. Precipitation of Al11RE3 particles with high melting point and high thermal stability along GB improves high temperature properties of AZ91 alloys.

  19. Afganistan and rare earths

    Emilian M. Dobrescu


    Full Text Available On our planet, over a quarter of new technologies for the economic production of industrial goods, are using rare earths, which are also called critical minerals and industries that rely on these precious items being worth of an estimated nearly five trillion dollars, or 5 percent of world gross domestic product. In the near future, competition will increase for the control of rare earth minerals embedded in high-tech products. Rare minerals are in the twenty-first century what oil accounted for in the twentieth century and coal in the nineteenth century: the engine of a new industrial revolution. Future energy will be produced increasingly by more sophisticated technological equipment based not just on steel and concrete, but incorporating significant quantities of metals and rare earths. Widespread application of these technologies will result in an exponential increase in demand for such minerals, and what is worrying is that minerals of this type are almost nowhere to be found in Europe and in other industrialized countries in the world, such as U.S. and Japan, but only in some Asian countries, like China and Afghanistan.

  20. Investigation of rare earth sealing of porous micro-arc oxidation coating formed on AZ91D magnesium alloy

    M.Laleh; Farzad Kargar; A.Sabour Rouhaghdam


    Magnesium and its alloys have been used in many industries,but they are reactive and require protection against aggressive environments.In this study,oxide coatings were applied on AZ91D magnesium alloy using micro-arc oxidation (MAO) process.Then,in order to seal the pores of the MAO coatings,the samples were immersed in cerium bath for different times.The surface morphologies and compositions of the coatings were analyzed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS),respectively.The corrosion behavior of the coatings was investigated with electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5 wt.% NaCl solution.The amount of the porosity of the coating was measured by electrochemical method.It was found that the sealing treatments by immersion in cerium bath successfully sealed the pores of the MAO coatings.The results of the corrosion tests showed that the MAO coating which was sealed in Ce bath for 10 min enhanced the corrosion resistance of the substrate significantly.Furthermore,this coating had the lowest amount of the porosity among the coatings.

  1. China Rare Earth Market Review


    @@ February, 2010 Rare earth separation plants and downstream producers like NdFeB magnetic materials and phosphor materials successively ceased production due to Spring Festival, Chinese New Year. Transactions in rare earth market were few affected by public holidays.

  2. China Rare Earth Market Review


    @@ Active demands from downstream industry drove the price rise of rare earth products in Chinese domestic marketrecently, particularly didymium and dysprosium products. Prices of other rare earth products remained stable.

  3. China rare earth market review


    Rare earth market fluctuated slightly recently and the transactions remained sluggish. Environment control was strengthened in southern China and many rare earth plants had gone out of production. Some traders were considering selling commodities at low p

  4. Microstructure, texture, and mechanical properties of friction stir spot welded rare-earth containing ZEK100 magnesium alloy sheets

    Rodriguez, R.I. [Department of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Jordon, J.B., E-mail: [Department of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Rao, H.M. [Department of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Badarinarayan, H.; Yuan, Wei [Hitachi America Ltd., R and D Division, Automotive Products Research Laboratory, Farmington Hills, MI 48335 (United States); El Kadiri, Haitham [Department of Mechanical Engineering, Mississippi State University, Starkville, MS 39759 (United States); Allison, P.G. [Department of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States)


    The effect of friction stir spot welding process parameters on the microstructure, texture, and mechanical properties of ZEK100 (Mg–1.0 wt% Zn–0.5 wt% RE–0.5 wt% Zr) Mg alloy was investigated. Lap-shear joints were prepared using two different tool rotational speeds (1500 and 2250 rpm) and three different shoulder plunge depths (0.0, 0.2, 0.6 mm). Microstructure analysis revealed significant grain refinement in the stir zone, when compared to the base material. Electron backscatter diffraction analysis revealed a strong texture development in the keyhole periphery and adjacent regions despite the presence of RE-elements, however, no significant texture variation was observed within the process parameters. These results suggest that the ultimate failure of the weld is more attributed to macroscopic features such as the bond width and upper sheet thickness rather than texture development.

  5. Hunan Rare Earth Group Approved


    <正>Following Guangdong,Guangxi,Fujian and Jiangxi,Hunan announced that it would consolidate its rare earth resources-the consolidation plan of Hunan Rare Earth Group has been approved. Consolidation of the rare earth industry of south China is in full swing.According to "Several Opinions of the State Council on Promoting the Sustainable and Healthy Development of Rare Earth Industry"(hereinafter referred to as "Several Opinions")released in 2011,

  6. China Rare Earth Market Review


    September 20-30, 2011 Rare earth market remained steady recently. Quoted prices of didymium products by separation and smelting plants kept stable. Some rare earth industrial zones in Baotou, Sichuan and Ganzhou had suspended production with the intensified environmental protection control and consolidation of rare earth industry. Persons in the industry hold a positive attitude toward the rare earth market after the National Day' s holiday in China. The market will develop healthily and orderly in the future.

  7. Non-rare earth magnetic nanoparticles

    Carpenter, Everett E.; Huba, Zachary J.; Carroll, Kyler J.; Farghaly, Ahmed; Khanna, Shiv N.; Qian, Meichun; Bertino, Massimo


    Continuous flow synthetic methods are used to make single phase magnetic metal alloy nanoparticles that do not contain rare earth metals. Soft and hard magnets made from the magnetic nanoparticles are used for a variety of purposes, e.g. in electric motors, communication devices, etc.

  8. China Rare Earth Market Review


    @@ Supply of rare earth concentrate remained tight recently. Rare earth market exhibited rising tendency holistically Affected by tight supply of rare earth concentrate, many plants were operated under the capacity. Supply of didymium oxide got tighter and the price was on rising.

  9. Japanese Rare Earth Market


    Since China cancelled export rebate in May this year,prices of magnetic materials related rare earth productscontinuously rose. Increasing production cost is largelyattributed to investment in environmental protectionequipments. Prices of Nd and Dy metals rose 20~30% over thebeginning of this year.Price of Nd was USD 11.5 - 12/Kg from USD 9/Kg at theend of 2004, up 30%. Price of Dy rose to USD 65- 70/Kg fromUSD 50/Kg early this year, up 20%. Price of Pr climbed to USD13.5 - 14/Kg from USD 11/Kg, up 30%. Pri...

  10. Oxidation, carburization and/or sulfidation resistant iron aluminide alloy

    Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier S.; Hajaligol, Mohammad R.; Lilly, Jr., A. Clifton


    The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, .ltoreq.1% Cr and either .gtoreq.0.05% Zr or Zro.sub.2 stringers extending perpendicular to an exposed surface of the heating element or .gtoreq.0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B. .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, .ltoreq.1% oxygen, .ltoreq.3% Cu, balance Fe.

  11. An assessment of the estimated thorium lung burdens of 130 miners in a rare-earth and iron mine in China

    Chen Xingan; Xiao Huijuan; Dong Zhihua; Lu Huimin; Yang Yingjie (Ministry of Public Health, Beijing, BJ (China). Lab. of Industrial Hygiene); Wang Jizhong; Wang Yidien; Li Shouhua; Hu Yaqin


    The thorium lung burdens of 130 miners in a rare-earth and iron mine were estimated by electrostatic collection of the decay products of exhaled thoron. The free-emanating {sup 224}Ra equivalents at the mouth of 73 individuals were higher than 1.0 pCi. The weighted mean value of {sup 224}Ra equivalents at the mouth of the 130 miners was 2.1{plus minus}0.3.Ci ({plus minus}S.E.). The corresponding weighted mean of 10 inhabitants of the same district was 0.8{plus minus}0.2.Ci. On the basis of the thorium lung burdens estimated from these results, and the dose-risk relationship obtained from epidemiological studies of miners exposed to radon daughters, the number of excess lung cancer cases among 2072 dust inhaling miners between 1958 and 1993 was calculated to be very small. A relationship was, however, found between the estimated thorium lung burdens and different stages of pneumoconiosis. (author).

  12. Separation and Recovery of Iron and Rare Earth from Bayan Obo Tailings by Magnetizing Roasting and (NH42SO4 Activation Roasting

    Yan Zhou


    Full Text Available A novel approach for recovery of iron and rare earth elements (REEs from Bayan Obo tailings of Baotou, China, was developed by combining magnetizing roasting, magnetic separation, (NH42SO4 activation roasting, and water leaching. Thermodynamic analysis of carbothermal reduction was conducted to determine the temperature of magnetizing roasting, and it agreed well with the experimental results. The maximum recovery of Fe reached 77.8% at 600 °C, and the grade of total Fe in the magnetic concentrate was 56.3 wt. %. An innovative approach, using water to leach REEs after (NH42SO4 activation roasting, was used to extract REEs from magnetic separation tailings. The main influence factors of the leaching recovery during (NH42SO4 activation roasting, were investigated with the mass ratio of (NH42SO4 to magnetic separation tailings, roasting temperature and roasting time. The leaching recoveries of La, Ce and Nd reached 83.12%, 76.64% and 77.35%, respectively, under the optimized conditions: a mass ratio of 6:1, a roasting temperature of 400 °C and a roasting time of 80 min. Furthermore, the phase composition and reaction process during the (NH42SO4 activation roasting were analyzed with X-ray diffraction (XRD, energy dispersive X-ray spectroscopy & scanning electron microscopy (EDS-SEM and thermogravimetry & differential scanning calorimetry (TG-DSC, and the leaching solution and leaching residue were also characterized.

  13. Characterization and recovery of rare earth elements from electronic scrap

    Bristøl, Lene Marie Lysgaard


    The rare earth elements are a group of 17 elements consisting of the lantahnide series, scandium and yttrium. The application with the largest rare earth consumption is the permanent rare earth magnets. The neodymium-iron-boron magnets are the strongest permanent magnetic material known and are widely used. There is a concern that there will be a shortage in Nd-Fe-B magnets in short time. This has lead to an increased interest in the recycling of the rare earth magnets in the world.This proje...

  14. China rare earth market review


    June 20-30 2012 Affected by a sustained slump in the demand from downstream industries, rare earth market remained flat recently. There were not many inquiries for rare earth products in the spot market. Consumers lacked of confidence in the future market. As for the downstream industries, the market of NdFeB magnetic materials and phosphors were in the doldrums. Ceramic, catalyst and polishing powder industries maintained weak. Affected by the global economy, export market of rare earth was weak.

  15. China rare earth market review


    Rare earth market remained weak recently. Dealings of light and heavy rare earth products were sluggish. Demand for didymium and dysprosium related products was soft and purchasers were not interested in replenishing their stocks. The market of NdFeB magnetic materials and phosphors remained inactive. Meanwhile, ceramic, catalyst and polishing powder industries were weak. Affected by global economical recession, export market of rare earth remained weak.

  16. China rare earth market review


    Rare earth market was weak recently. There was still no sign of recovery in NdFeB magnetic materials and phosphors market. The market of ceramic, catalyst and polishing powder were in the doldrums. Rare earth deep processing enterprisers hesitated to purchase rare earth products and considered that there was room for further price reduction. Global economy slowed down and there was no sign of improvement yet. The export market was sluggish and transactions were inactive.

  17. China Rare Earth Market Review


    Rare earth market was relatively stable recently. There was not much change to the quotations by suppliers. Inquiries for most products increased in spot market and so did to the transactions. Recently, rare earth special invoices attracted the attention in the industry again. It is likely to result in price rise of many rare earth products if the special invoice system can put into effect in the near term.

  18. China rare earth market review


    November 1-10, 2012 Some key rare earth producers had paused production since the last ten day period of October in order to retain normal production and market order and stabilize rare earth prices. The production suspension measure by the plants together with severe cracking down on illegal mining by the government had some influence on sluggish market recently. Data showed rapid price increase of major rare earth products after sharp decline previously.

  19. China rare earth market review


    October 21-31,2012 Recently, dealings of rare earth remained stagnant. Consumers hesitated to increase their stocks for the fear of further decline in rare earth prices. It was difficult for suppliers to sell products and they had reduced quotations to attract buyers. It did not show demand from end users could rebound in short terms. Dealings of rare earth products in spot market were few. The market of NdFeB magnetic materials, phosphors, catalysts, polishing powders and ceramics remained sluggish. There was no sign of picking up in world economy. Export market of rare earths maintained inactive.

  20. China Rare Earth Market Review


    Rare earth market remained sluggish and quiet holistically recently. Didymium-related market was quiet and the consumers were hesitating in replenishing their inventories. Inquiries for dysprosium-related products were few and the transactions were inactive, Demand for europium oxide (99.99%) was weak and the trade was far from brisk. Baogang Rare Earth suspended production, which has a positive effect in stabilizing the whole rare earth market. But prices of rare earth products did not go up rapidly. This means there were still large inventories in the market.

  1. Baotou Rare Earth Became the World’s Biggest High Performance Magnetic Material Base


    <正>The High Performance Magnetic Material Phase II Project,an industry upgrading project implemented by Inner Mongolia Baotou Iron&Steel Rare Earth(Group)Hi-tech Co.,Ltd,recently basically finished equipment commissioning,signifying that the enterprise had developed the production capacity of15000 t/a Nd-Fe-B strip casting alloy and 5000t/a Nd-Fe-B magnet,thus becoming the world’s

  2. China's rare-earth industry

    Tse, Pui-Kwan


    Introduction China's dominant position as the producer of over 95 percent of the world output of rare-earth minerals and rapid increases in the consumption of rare earths owing to the emergence of new clean-energy and defense-related technologies, combined with China's decisions to restrict exports of rare earths, have resulted in heightened concerns about the future availability of rare earths. As a result, industrial countries such as Japan, the United States, and countries of the European Union face tighter supplies and higher prices for rare earths. This paper briefly reviews China's rare-earth production, consumption, and reserves and the important policies and regulations regarding the production and trade of rare earths, including recently announced export quotas. The 15 lanthanide elements-lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium (atomic numbers 57-71)-were originally known as the rare earths from their occurrence in oxides mixtures. Recently, some researchers have included two other elements-scandium and yttrium-in their discussion of rare earths. Yttrium (atomic number 39), which lies above lanthanum in transition group III of the periodic table and has a similar 3+ ion with a noble gas core, has both atomic and ionic radii similar in size to those of terbium and dysprosium and is generally found in nature with lanthanides. Scandium (atomic number 21) has a smaller ionic radius than yttrium and the lanthanides, and its chemical behavior is intermediate between that of aluminum and the lanthanides. It is found in nature with the lanthanides and yttrium. Rare earths are used widely in high-technology and clean-energy products because they impart special properties of magnetism, luminescence, and strength. Rare earths are also used in weapon systems to obtain the same properties.

  3. Phase stable rare earth garnets

    Kuntz, Joshua D.; Cherepy, Nerine J.; Roberts, Jeffery J.; Payne, Stephen A.


    A transparent ceramic according to one embodiment includes a rare earth garnet comprising A.sub.hB.sub.iC.sub.jO.sub.12, where h is 3.+-.10%, i is 2.+-.10%, and j is 3.+-.10%. A includes a rare earth element or a mixture of rare earth elements, B includes at least one of aluminum, gallium and scandium, and C includes at least one of aluminum, gallium and scandium, where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet. In one embodiment, the rare earth garment has scintillation properties. A radiation detector in one embodiment includes a transparent ceramic as described above and a photo detector optically coupled to the rare earth garnet.

  4. Mechanism of the high transition temperature for the 1111-type iron-based superconductors R FeAsO (R =rare earth ): Synergistic effects of local structures and 4 f electrons

    Zhang, Lifang; Meng, Junling; Liu, Xiaojuan; Yao, Fen; Meng, Jian; Zhang, Hongjie


    Among the iron-based superconductors, the 1111-type Fe-As-based superconductors REFeAs O1 -xFx (RE = rare earth) exhibit high transition temperatures (Tc) above 40 K. We perform first-principles calculations based on density functional theory with the consideration of both electronic correlations and spin-orbit couplings on rare earths and Fe ions to study the underlying mechanism as the microscopic structural distortions in REFeAsO tuned by both lanthanide contraction and external strain. The electronic structures evolve similarly in both cases. It is found that there exist an optimal structural regime that will not only initialize but also optimize the orbital fluctuations due to the competing Fe-As and Fe-Fe crystal fields. We also find that the key structural features in REFeAsO, such as As-Fe-As bond angle, intrinsically induce the modification of the Fermi surface and dynamic spin fluctuation. These results suggest that the superconductivity is mediated by antiferromagnetic spin fluctuations. Simultaneously, we show that the rare-earth 4 f electrons play important roles on the high transition temperature whose behavior might be analogous to that of the heavy-fermion superconductors. The superconductivity of these 1111-type iron-based superconductors with high-Tc is considered to originate from the synergistic effects of local structures and 4 f electrons.

  5. The Redox Dynamics of Iron in a Seasonally Waterlogged Forest Soil (Chaux Forest, Eastern France) Traced with Rare Earth Element Distribution Patterns

    Steinmann, M.; Floch, A. L.; Lucot, E.; Badot, P. M.


    The oxyhydroxides of iron are common soil minerals and known to control the availability of various major and trace elements essential for biogeochemical processes. We present a study from acidic natural forest soils, where reducing redox conditions due to seasonal waterlogging lead to the dissolution of Fe-oxyhydroxides, and to the release of Fe to soil water. In order to study in detail the mechanism of redox cycling of Fe, we used Rare Earth Element (REE) distribution patterns, because an earlier study has shown that they are a suitable tool to identify trace metal sources during soil reduction in wetland soils (Davranche et al., 2011). The REE patterns of soil leachates obtained with the modified 3-step BCR extraction scheme of Rauret et al., (1999) were compared with those of natural soil water. The adsorbed fractions (F1 leach), the reducible fraction of the deepest soil horizon H4 (F2 leach, 50-120 cm), and the oxidizable fractions of horizons H2 to H4 (F3 leachs, 24-120 cm) yielded REE patterns almost identical to soil water (see figure), showing that the REE and trace metal content of soil water was mainly derived from the F1 pool, and from the F2 and F3 pools of the clay mineral-rich deep soil horizons. In contrast, the F2 leach mobilized mainly Fe-oxyhydroxides associated with organic matter of the surface soil and yielded REE patterns significantly different from those of soil water. These results suggest that the trace metal content of soil water in hydromorphic soils is primarily controlled by the clay fraction of the deeper soil horizons and not by organic matter and related Fe-oxyhydroxides of the surface soil. Additional analyses are in progress in order to verify whether the REE and trace metals of the deeper soil horizons were directly derived from clay minerals or from associated Fe-oxyhydroxide coatings. Refs cited: Davranche et al. (2011), Chem. Geol. 284; Rauret et al. (1999), J. Environ. Monit. 1.

  6. China rare earth market review


    Rare earth market remained stagnant recently. The buyers did not show willingness to replenish raw materials affected by weak demand. Most persons in rare earth circle were not confident with the short-term rare earth market. Demand for didymium mischmetal was soft recently. The market of dysprosium related products was quiet and NdFeB magnet producers were inactive in the purchase. Phosphor market was stagnant as well. Buyers were cautious on replenishing the material. There were few inquiries for europium oxide (99.9%) in spot market and transactions were difficult.

  7. 6061铝合金无铬磷酸盐稀土转化膜的腐蚀性研究%Study on the Corrosion Resistance of Chromium -Free Phosphate Rare Earth Conversion Coating on 6061 Aluminum Alloy

    李红玲; 孟志芬; 韩延安; 娄淑芳; 李杰; 李文静


    测试了磷酸盐转化膜和稀土促进的转化膜在不同pH溶液中的极化曲线、时间-电位曲线和电化学阻抗谱(EIS),对磷酸盐转化膜的耐蚀性能进行了研究.电化学测试表明:稀土磷酸盐处理后的铝合金试样的阳极极化电流下降;交流阻抗测试结果显示:由稀土促进生成的磷酸盐化学转化膜具有较大的极化电阻,二者都说明经稀土促进的转化膜的耐腐蚀性能得到了加强.%The corrosion resistance of phosphate conversion coating was studied by the polarization curves, time - potential curves and electrochemical impedance spectroscopy of phosphate conversion coating in solutions with different pH values. Electrochemical tests showed that anodic polarization current of alumi num alloy treated by rare earth phosphate declined and AC impedance test results indicated that phosphate conversion coating activated by rare earth gave a large polarization resistance. Both indicated that the corro sion resistance of phosphate conversion coating activated by rare earth were enhanced.

  8. Refining Effect of a New Al3Ti1B1RE Master Alloy on Al Sheets Used for Can Manufacture and Behavior of Rare Earths in Master Alloy

    傅高升; 陈文哲; 钱匡武


    The refining effect of Al3Ti1B1RE master alloy on Al sheets used for pressure can manufacture and the behavior of mixed rare earths (RE) in master alloy were investigated with XRD, OM, SEM and EDAX. It is found that the refining effect of the refiner on the material has superiority over foreign or domestic Al5Ti1B refiner, and the refiner still retains its refining ability for 6 h after adding it to molten Al, thus improving the strength and plasticity of the material remarkably. The excellent refining effect and stability of AlTiBRE refiner result from that RE can lower the surface energy of molten Al and improve the wetting characteristics of molten Al on refinement nuclei such as TiAl3, TiB2, etc., thus giving full play to the effect of heterogeneous nucleation and impeding the congregating tendency of TiB2 phase in molten Al. At the same time, RE gathering in front of solid/liquid interface are also easy to cause composition supercooling in molten Al, thus impeding the growth of α-Al grains and promoting α-Al nucleation on refinement nuclei. In addition, RE also play certain role in purification and grain refinement, or modification, especially their effect of purification can improve the metallurgical quality of AlTiBRE master alloy.

  9. China Rare Earth Holdings Limited


    China Rare Earth Holdings Limited is a large trans-area corporation and a public company listed in Hong Kong Stock Exchange (Name: China Rare Earth, Code: 0769), with headquarter in Hong Kong. Located on the bank of beautiful Taihu Lake, the subsidiary in Yinxing covers area of 200,000 m2. It has nearly 1,000 employees, 30% of whom are technical staffs. After self-administration and effort, the company passed ISO 9001: 2000 and ISO 14000 Certificaitons.

  10. China Rare Earth Market Review


    Rare earth market remained depressed after the New Year affected by the weak demand. Purchaser preferred to consume inventories rather than increase the stockpile. There was a strong wait-and-see atmosphere in the market. Driven by the intense desire to sell out the commodities, traders further decreased their quoted price for rare earth products. Most persons in the market preferred to hold commodities and waited for a rise in the market after the Spring Festival.

  11. China rare earth market review


    March 21-31,2012 Rare earth market rebounded holistically recently. Price of didymium products rose slightly after being stable for one month. There were also increases in the prices of europium oxide and terbium oxide, which led to a rush by phosphor plants. The market of yttrium-medium and europium-rich minerals remained stagnant though the rare earth market recovered. Price of the mineral was around RMB ¥210,000-250,000/ton.

  12. Wide frequencies range of spin excitations in a rare-earth Bi-doped iron garnet with a giant Faraday rotation

    Parchenko, Sergii; Stupakiewicz, Andrzej; Yoshimine, Isao; Satoh, Takuya; Maziewski, Andrzej


    Ultrafast magnetization dynamics of a rare-earth Bi-doped garnet were studied using an optical pump-probe technique via the inverse Faraday effect. We observed a wide range of frequency modes of the magnetization precession, covering two orders of magnitude. The excitation efficiency of low-frequency precessions in the GHz range, together with a significant beating effect, strongly depended on the amplitude of the external magnetic field. On the contrary, high-frequency precession was independent of the external magnetic field. The obtained results may be exploited in the development of wide class of microwave and magneto-optical devices.

  13. Investigation of Crystalline Iron-Platinum Nickel and Amorphous Rare Earth-Iron Alloys for Permanent Magnets.


    AppI . Phys. 52, 2549 (1981). 3. S. G. Cornelison, D. J. Sellmyer and G. Hadjipanayis, J. Appl. Phys. 52, 1823 (1981). li * . 4. G. Hadjipanayis, M. Sc...23, 3349 (1981). 9. A. E. Clark, AppI . Phys. Lett. 23, 642 (1973). 10. H. T. Savage, A. E. Clark, S. J. Pickart, J. J. Rhyne and H. A. Alperin, IEEE...Trans. Magn. MAG-lO, 807 (1974). S 11. J.J. Croat, IEEE Trans. Magn. MAG-18, 1442 (1982). 12. N. C. Koon and B. N. Das, Appi . Phys. Lett. 39, 840 (1981

  14. Rare Earth Separation in China


    During the last decade, China rare earth (RE) industry has made significant progress and become one of the most important producers in the world. In this paper, the recent developments in both fundamental research and industrial application are briefly reviewed: (1) the development and application of Theory of Countercurrent Extraction, (2) the novel solvent extraction process and its application in industry for separating heavy rare earth elements (Tm, Yb, Lu), yttrium (Y), and scandium (Sc), (3) the on-line analysis and automatic control of countercurrent extraction, (4) the eco-friendly process for RE/Th separation of bastnasite in Sichuan Province and electrochemical process for Eu/RE separation, and (5) the optimized flowcharts for typical rare earth minerals in China.

  15. China Rare Earth Market Review


    August 20-31, 2011 Rare earth market did not show the sign of picking-up and remained stagnant recently. Most suppliers continued to decrease their quoted price, but leading producers in northern and southern China did not adjust their quoted price. Most rare earth plants in southern China had not yet resumed production. Quoted price of didymium products swung and the quoted prices of dysprosium-related products were slipping affected by weak demand. Inquiries for europium oxide were decreasing affected by the slow phosphor market.

  16. Development Trend of Rare Earth Standardion Work

    Ma Jie; Lin Jirong; Zhao Fei; Zhang Xiuyan


    Rare earth standardization was developed along with rare earth industry.In recent decades, great advances have been made in China rare earth industry.This paper describes the status of rare earth standardization, problems existed and ways to perfect.Now the number of Chinese Rare Earth Standards has increased to 232 with expanding of the categories and covering scope of rare earth products.But the present standard system cannot be completely suited with rare earth production and trade, and not keep pace with the advance of technology.Standards are important rules in world trade and must be acted on.

  17. Thermal shock behavior of rare earth modified alumina ceramic composites

    Sun, Junlong; Liu, Changxia [Ludong Univ., Yantai (China). School of Transportation


    Alumina matrix ceramic composites toughened by AlTiC master alloys, diopside and rare earths were fabricated by hot-pressing and their thermal shock behavior was investigated and compared with that of monolithic alumina. Results showed that the critical thermal shock temperature (ΔT) of monolithic alumina was 400 C. However, it decreased to 300 C for alumina incorporating only AlTiC master alloys, and increased with further addition of diopside and rare earths. Improvement of thermal shock resistance was obtained for alumina ceramic composites containing 9.5 wt.% AlTiC master alloys and 0.5 wt.% rare earth additions, which was mainly attributed to the formation of elongated grains in the composites.

  18. China Rare Earth Market Review


    June 20-30, 2011 Prices of heavy rare earth products remained soaring. The same happened to dysprosium and its related products due to tight supply. Separation plants held tightly of europium oxide. Refining plants took a positive attitude toward the ma

  19. Effect of Heat-Treatment Process on Properties of Rare Earth Mg-Based System Hydrogen Storage Alloys with AB3-Type


    The effect of heat-treatment process on the properties of Mm0.8Mg0.2(NiCoAlMn)3.5 hydrogen storage alloy was discussed. The electrochemical properties such as cycling stability, activation property, and the plateau voltage of the alloy which was heat-treated in various temperatures and times had different changes during the cycle process, the optimum heat-treatment conditions of this alloy were determined by this work.

  20. Rare Earth Oxide Thin Films

    Fanciulli, Marco


    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  1. Rare Earths and Magnetic Refrigeration


    Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.

  2. China Rare Earth Market Review


    November 20-30.2011 Weak demand resulted in the slack rare market. Consumers did not intend to rep earth enish inventories yet and transactions of rare earth products were stagnant. The market of didymium-related products was in the doldrums. Demand for dysprosium-related products was sluggish. Inquiries for europium oxide (99.9%) were few and dealings of the product were difficult.

  3. Study on Hydrogen in Mixed Gas Separated by Rare Earth Hydrogen Storage Alloys%稀土贮氢合金分离混合气体中氢气的研究

    郭世海; 王国清; 赵栋梁; 张羊换; 王新林


    采用中频感应炉在氩气保护下制备稀土镍系AB型贮氢合金和La-Mg-Ni系AB型贮氢合金.利用H、N和CH配制的混合气体来模拟工业尾气,对利用稀土贮氢合金分离混合气体中氢气的纯度、合金抗杂质气体毒化及抗粉化性能进行研究.结果表明,稀土镍系AB型合金由CaCu型结构组成,AB型La-Mg-Ni系合金为多相结构,由(La,Mg)Ni、LaNi以及LaNi型相组成.在分离混合气体中氢气时,贮氢合金均受到杂质气体的毒化,导致吸氢速率降低,吸氢量减少.La-Mg-Ni系合金的抗粉化性能好于LaNi5及其多元化合金.综合考虑分离氢气的纯度、合金的抗毒化及抗粉化性能,认为LaNi 7MnAlFeCo合金分离氢气的效果较好,氢气纯度可以达到90.7%.%AB5-type rare-earth nickel(RE-Ni)based hydrogen storage alloys and AB3-type La-Mg-Ni based hydrogen storage alloys were prepared by vacuum medium-frequency induction melting in argon atmosphere. Industrial offgas was simulated by the mixed gas including H2, N2 and CH. The purity of hydrogen separated by rare-earth hydrogen storage alloys and anti-poison and anti-pulverization properties of the alloys in the process of hydrogen absorption and desorption were studied. The results show that AB5-type RE-Ni based hydrogen storage alloys are possessed of the single structure with CaCus-type, and AB3-type La-Mg-Ni based hydrogen storage alloys are possessed of the multi-phase structure with(La,Mg)Ni, LaNi and LaNi phase. The hydrogen storage alloys will be poisoned by impurity gas in the separation of hydrogen, resulting in lower speed rate of hydrogen absorption and lesser capacity of hydrogen absorption. The anti-pulverization property of La-Mg-Ni based alloys is better than that of LaNi alloy and its complex alloy. LaNi.TMno.4Al0.3Fe0.4Co0.2 alloy is considered as better alloy to separate hydrogen from the mixed gas, con-sidering the purity of separated hydrogen, anti-poison and anti-pulverization property of

  4. Research on Direct Reduction of Baotou Rare Earth Tailings to Recover Iron%包头稀土尾矿回收铁的直接还原研究

    杨合; 荣宜; 薛向欣; 梁海军


    In order to recycle the iron in the rare earth tailings and take account of the concentration of niobium and rare earth,the " direct reduction with coal-weak magnetic separation" was adopted on the rare earth tailings to cany out the experiment. The experiment schedules were designed as follows; The influences of roasting temperature,soaking time and fixed C/0 on the metallization rate were researched. According to the result of this paper,when the roasting temperature was 1200℃ ,soaking time was 2 h and fixed C/O was 1. 00,the metallization rate of the direct reduction production could reach 86. 59% . In the experiment of weak magnetic separation,the influences of magnetic density on grade,yield and recovery of the rare-earth tailings reduced with coal were researched. The following results were found out through the study; The iron concentrate is 82. 36% in grade,32.08% in yield and 82. 91% in recovery,when the magnetic density is 160 kA·m-1. Rare earth and niobium were both concentrated in the weak magnetic separation tailings.%为了对包头稀土尾矿中的铁进行回收,同时兼顾稀土、铌的富集,采用“煤基直接还原—弱磁选”对稀土浮选尾矿进行了铁的回收试验.考察了焙烧温度、保温时间、配碳比对直接还原产品的金属化率的影响,以及磁场强度对磁选产品铁的品位、回收率和产率的影响.研究发现:在磨矿粒度-200目,焙烧温度为1200℃,保温时间为2h,固定C/O=1.00的条件下,采用煤基直接还原,得到金属化率86.59%的还原矿;再对还原矿采用磁选管以160 kA·m-1的磁场强度进行弱磁选,从TFe=25.40%的稀土尾矿获得的磁选产品全铁品位达到82.36%,产率为32.08%,回收率达82.91%,稀土、铌均在磁选渣中富集.

  5. Effect of rare earth additions on magnetic properties of Fe{sub 82}Nb{sub 2}B{sub 14}RE{sub 2} (RE = Y, Gd, Tb and Dy) amorphous alloys

    Chrobak, A., E-mail: [Institute of Physics, Silesian University, 4 Uniwersytecka, 40-007 Katowice (Poland); Nosenko, V. [G.V. Kurdyumov Institute for Physics of Metals, NAS of Ukraine, Vernadsky ave. 36, 03142 Kyiv (Ukraine); Haneczok, G. [University of Silesia, Institute of Materials Science, 12 Bankowa, 40-007 Katowice (Poland); Boichyshyn, L.; Kotur, B. [Ivan Franko National University of Lviv, Kyryla and Mefodia St. 6, 79005 Lviv (Ukraine); Bajorek, A. [Institute of Physics, Silesian University, 4 Uniwersytecka, 40-007 Katowice (Poland); Zivotsky, O.; Hendrych, A. [Technical University of Ostrava, Institute of Physics, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)


    Highlights: {yields} We studied magnetic properties of Fe{sub 82}Nb{sub 2}B{sub 14}RE{sub 2} (RE=Y,Gd,Tb,Dy) amorphous alloys. {yields} In a comparison with Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} alloy the rare earth editions cause an increase of the Curie temperature and a decrease of magnetic moment per magnetic atom. {yields} Doping of Tb and Dy lead to a strong decrease of magnetic permeability and a formation of low dimensional finger-print magnetic domains. - Abstract: In the present paper the influence of RE alloying additions (Y, Gd, Tb and Dy) on magnetic properties (Curie temperatures, low temperature magnetization, zero field cooling-field cooling curves, domain structure, room temperature magnetostriction and magnetic permeability) of amorphous alloys of type Fe{sub 82}Nb{sub 2}B{sub 14}RE{sub 2} are carefully examined. It was shown that substituting of yttrium atoms by magnetic elements, i.e. Gd, Tb and Dy leads to (i) an increase of the Curie temperature of amorphous phase from 416 K (for Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2}) to 450 K (for Fe{sub 82}Nb{sub 2}B{sub 14}Gd{sub 2}) and (ii) a decrease of magnetization in saturation (magnetic field 7 T) which can be explained by antiferromagnetic Fe-RE coupling resulting in a decrease of magnetic moment calculated per magnetic atom from 2.00 {mu}{sub B} for the Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} alloy (Fe in amorphous phase) to 1.51 {mu}{sub B} for the Fe{sub 82}Nb{sub 2}B{sub 14}Tb{sub 2} alloy. It was concluded that Tb and Dy alloying additions introduce a local magnetic anisotropy responsible for significant decrease of initial magnetic permeability (about 5 times in relation to Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} or Fe{sub 82}Nb{sub 2}B{sub 14}Gd{sub 2} alloy), increase of magnetic irreversibility effect measured at 2 K (about 10 times in relation to the same alloys) and appearing of the finger-print magnetic domain regions (not observed for the Fe{sub 82}Nb{sub 2}B{sub 14}Y{sub 2} and Fe{sub 82}Nb

  6. 2006 Rare Earth Export Quota


    @@ According to correlative stipulations in "Goods Import εt Export Administrating Statute of P.R.C", 2006export quota for important industrial products was issued by the Ministry of Commerce of P.R.C. on December 30th of 2005. Export quota of rare earth products is 45,000 tons. It is said the quota will be distributed in two batches. The first batch of quota will reach 70-80% of the total with 21,700 - 24,800tons for domestic companies and 10,500 - 12,000 tons for foreign invested companies. Quota will be distributed to relevant enterprises directly in recent days.

  7. Research on Rare Earth Encapsulated Luminescent Material

    Yu Zhiwei; Liu Chengdong; Qi Xiaopeng


    A new method of preparation of irradiative material by using rare earth as luminophor and inorganic powder as base nucleus was presented.Rare earth was used to make colloid, which was mixed with base nucleus solution,where deposition/attachment reaction took place and rare earth was adhered onto the surface of base nucleus, hence yielding a new rare earth encapsulated irradiative material.Fluorescent spectrum analysis shows that this material possesses two emission peaks, one within 400 ~ 500 nm and the other within 580 ~ 700 nm, reflecting the luminous characteristics of original rare earth material.

  8. The Chinese Society of Rare Earth is Studying The Feasibility of Marketing Rare Earth Futures


    Lin Donglu,secretary-general of the Chinese Society of Rare Earth recently said,the Chinese Society of Rare Earth undertook the research on subject of the National Social Science Fund Foundation on the reform of Chinese rare earth trading pricing mechanism on promoting RMB globalization,and is focusing on studying the feasibility of marketing rare earth futures variety.

  9. 稀土和磷对过共晶Al-Si合金的复合变质作用%Multiplex modification with rare earth elements and P for hypereutectic Al-Si alloys

    欧阳志英; 毛协民; 红梅


    The effect of rare earth (RE) elements on the morphologies and sizes of Si phases in the hypereutectic Al-Si alloys modified with P was investigated. The results show that the addition of La element to the hypereutectic Al-Si alloys can enhance the effect of P element on the modification of the primary Si phases. In the multiplex modification of RE-P, the primary Si phase is refiner and the shape of the eutectic Si is changed from long needle-like to short rod-like. Moreover, the agglomeration rate of the primary Si phase is slowed greatly. Even the melt is held for 6 h, the average size of the primary Si phase is still satisfied. The results analyzed by scanning electron microscope (SEM) indicate that La is richer at Al-Si interface than that in α-Al or primary Si phase. The higher the La content in the Al-Si interface, the smaller the primary Si phase.

  10. Effect of rare-earth elements on nanophase evolution, crystallization behaviour and mechanical properties in Al–Ni–R (R = La/Mischmetal) amorphous alloys

    K L Sahoo; Amitava Mitra; Sukomal Ghosh


    The crystallization behaviour and evolution of nanoparticles in amorphous Al–Ni–Mischmetal (Mm) and Al–Ni–La alloys during heat treatment have been studied. Rapidly solidified ribbons were obtained by induction melting and ejecting the melt onto a rotating Cu wheel in an Ar atmosphere. The crystallization behaviour of the melt-spun ribbons was investigated using differential scanning calorimetry and X-ray diffractometry (XRD). XRD studies confirmed that all the ribbons were fully amorphous. Al–Ni–Mm systems showed a three-stage crystallization process whereas Al–Ni–La system, in general, showed a two-stage crystallization process on annealing. Crystallization kinetics was analysed by Kissinger and Johnson–Mehl–Avrami approaches. In Al–Ni–La alloys, the crystallization pathways depend on the La concentration. Microhardness of all the ribbons was examined at different temperatures and correlated with the corresponding evolution of phases.

  11. Study of yttrium-based heavy rare earth compacted graphite cast iron high temperature properties%钇基重稀土蠕墨铸铁的高温性能研究

    王敏毅; 黄颖; 林有希


    Compacted graphite cast iron was prepared by using of local rich resources of yttrium -based heavy rare earth. Several properties, such as tensile strength of gray cast iron and compacted graphite cast iron under condition of high temperature, oxidation weight increase value, percentage e-longation, heat fatigue resistance and linear expansion coefficient were discussed. Two kinds of castings linear regression equation for expansion coefficient were proposed. The results showed that fracturing properties of compacted graphite cast iron was dimple fracture in high temperature, and tensile strength of compacted graphite cast iron is mush stronger than that of gray cast iron in high temperature. In addition, compacted graphite cast iron behaved better in anti -oxidizing and anti -weight increasing than gray cast iron and the former thermal expansion coefficient is close to the latter. Moreover, they have similar linear expansion coefficient and phase change of grey cast iron shrinked much more severe than that compacted graphite cast iron.%利用钇基重稀土资源熔炼蠕墨铸铁,探讨高温条件下灰铸铁和蠕墨铸铁的抗拉强度、氧化增重值、伸长百分率、耐热疲劳性和线性膨胀系数等性能,同时用数理统计的方法推导出两种铸件线性膨胀系数的回归方程.结果表明:高温下蠕墨铸铁的断裂性质为韧窝断裂,其高温抗拉强度明显比灰铸铁高;蠕墨铸铁的抗氧化性和抗生长性均比灰铸铁好而导热系数与灰铸铁相近;灰铸铁和蠕墨铸铁的线性膨胀系数相近,但灰铸铁的相变收缩要比蠕墨铸铁强烈得多.

  12. 某稀土合金生产线职业病危害作业分级调查与评价%Investigation and Evaluation of Occupational Hazards Classification At Workplacein the Production Line of Rare Earth Alloy

    牛兆煜; 王志英


    Objective To identify and analyze occupational hazards in the productionline of Rare earth alloy ,To Classificate Oc-cupational Hazards At Workplace, and provide scientific and effective datas for regulators and occupational health management . Methods Field investigation and detection of occupational risk factors and occupational health monitoring were applied. Combined with the relerant standard, Occupational Hazards Classification At Workplace were carried out and according to the enterprise ’s conditions,the improving measures were put forward.Results The main occupational hazards were rare-earth dust,chemical toxi-cant(hydrogen fluoride,carbon monoxide,carbon dioxide,etc) ,high temperature and noise.The time weighted average concentra-tions of dust accorded with national standards pass rate was 58.8%. The work classification of rare earthdust bout 2# Electrolytic workshop wasⅡ (morderrate damage work); The work classification of rare earthdust bout other Electrolytic workshop wasⅠ(mild damage work); the qualified rate of noise and chemical toxicant in workplaces was100%.Conclusion The rare earth dust hazard is serious at Electrolytic workshop in this enterprise,According to current situation of rare earth dust concentration exceeding the re-quirement of national standards , the effective operation of occupational hazards prevention facilities Should strengthen, Make per-fect the rules and regulations of the occupational disease.%目的:对某稀土合金生产线职业病危害因素进行识别、分析,对职业病危害作业进行分级,为监管部门和企业职业卫生管理提供科学有效的数据。方法采用职业卫生现场调查法、职业病危害因素检测法、职业健康监护等方法并结合国家职业卫生相关标准对职业病危害作业进行分级,并根据企业现有情况,提出针对性整改措施。结果该项目职业病危害因素为稀土粉尘、氟化氢、一氧化碳、二氧化碳、高温

  13. Influence of rare earth on the microstructure and age hardening response of indirect-extruded Mg-5Sn-4Zn alloy

    程伟丽; PARK; S; S; 唐伟能; KOO; B; H


    The effects of Ce addition on the microstructure, age hardening response and mechanical properties of an indirect-extruded Mg-5wt.%Sn-4Zn (TZ54) alloy were investigated. Addition of Ce accelerated the aging response with the peak aging time moving from 300 h in TZ54 to 30 h in Mg-5wt.%Sn-4Zn-1Ce (TZE541), while the peak harness was similar to each other. The addition of Ce also caused an increase in the precipitation stability during overageing. Though the tensile strength of extruded TZ54 was improved by t...

  14. Influence of Zr Addition on Structure and Performance of Rare Earth Mg-Based Alloys as Anodes in Ni/MH Battery

    Shujun Qiu


    Full Text Available In this study, the substitution of Mg with Zr in La0.7Mg0.3(Ni0.85Co0.153.5 was carried out with the purpose of improving the electrochemical performances. The structural and hydrogen storage properties in both gas-solid reaction and the electrochemical system were systematically studied on La0.7(Mg0.3−xZrx(Ni0.85Co0.153.5 (x = 0.05, 0.1, 0.2, 0.3 alloys. Each tested alloy is composed of LaNi3 phase, LaNi5 phase and ZrNi3 phase with different phase abundances. The electrochemical studies indicated that all Zr-substituted anodes possessed a much higher cycling capacity retention than pristine La0.7Mg0.3(Ni0.85Co0.153.5. However, the maximum discharge capacity was reduced with the increase of Zr content. The potential-step tests showed that the diffusion of hydrogen atoms inside the anodes was decelerated after the introduction of Zr.

  15. Process for making a high toughness-high strength iron alloy

    Stephens, J. R.; Witzke, W. R. (Inventor)


    A steel alloy is produced by a process which includes using cold rolling at room temperature and subsequent heat treatment at temperatures ranging from 500 C to 650 C. The resulting alloys exhibits excellent strength and toughness characteristics at cryogenic temperatures. This alloy consists essentially of about 10 to 16 percent by weight nickel, to about 1.0 percent by weight aluminum, and 0 to about 3 percent by weight of at least one of the following additional elements: copper, lanthanum, niobium, tantalum, titanium, vanadium, yttrium, zirconium and the rare earth metals, with the balance being essentially iron. The improved alloy possesses a fracture toughness ranging from 200 to 230 ksi sq in. and yield strengths up to 230 ksi.

  16. High toughness-high strength iron alloy

    Stephens, J. R.; Witzke, W. R. (Inventor)


    An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

  17. Funing Rare Earths Industrial Co. Ltd


    The company covers separation with whole lines of light, medium and heavy rare earths, with annual separation volume of rare earth oxides of 4,500 tons. It also produces rare earth oxides, fluorides and salts. Products with high-purity and super-high-purity are produced according to customer's request. Under the technological guidance of domestic experts and application of modern high-pressure

  18. Review on Rare Earth/Polymer Composite

    刘力; 张立群; 赵素合; 金日光; 刘美琳


    The special properties of rare earth/polymer composite were described. More emph asis was put on the radiation shielding and magnetic properties. In the applicat ion to X-ray shielding, rare earth/polymer composite can make up the feeble abs o rbing area. If the rare earth content is high enough, it can demonstrate strong ability for thermal neutron absorption; The composite has strong paramagnetism. The feasibility of preparing magnetic rare earth/polymer composite was discussed . In addition, three preparation methods were introduced: simple polymerization, mixing and reaction processing. The effect of the rare earth/polymer composites pre -sturcture and the coordinate number of rare earth ions on the light property w as a nalyzed. Rare earth/polymer composite may have the structure and property simlar to those of the ionomer. The feasibility of the in-situ preparation of the rare earth/polymer nano structure is indicated. Besides, the relationship betwe en structure and properties of the rare earth/polymer composite was discussed. T he problems associated with such composite materials were also presented.

  19. Rare earth effect of yttrium on formation and property of Cr2O3 oxide film formed on Co-Cr binary alloy

    JIN Huiming; FELIX A. Congrado; AROYAVE M. Hayara


    The isothermal oxidizing kinetics of Co-40Cr alloy and its yttrium ion-implanted samples were studied at 1000℃ in air by thermal-gravity analysis (TGA). Scanning electronic microscopy (SEM) was used to examine the Cr2O3 oxide film's morphology after oxidation. Secondary ion mass spectrum (SIMS) method was used to examine the binding energy change of chromium caused by Y-doping and its influence on formation of Cr2O3 film. Acoustic emission (AE) method was used in situ to monitor the cracking and spalling of oxide films formed on both samples during oxidizing and subsequent air-cooling stages. Theoretical model simulating the film fracture process was proposed to analyze the acoustic emission spectrum both on time domain and on AE-event number domain. It is found that yttrium ionimplantation can remarkably reduce the isothermal oxidizing rate of Co-40Cr and improve the anti-cracking and anti-spalling properties of Cr2O3 oxide film. Reasons for the improvement are mainly that the implanted yttrium can reduce the grain size of Cr2O3 oxide, increase the high temperature plasticity of oxide film, and remarkably reduce the number and size of Cr2O3/Co-40Cr interfacial defects.

  20. Recycling of Rare Earth Elements

    Lorenz, Tom; Bertau, Martin


    Any development of an effective process for rare earth (RE) recycling has become more and more challenging, especially in recent years. Since 2011, when commodity prices of REs had met their all-time maximum, prices have dropped rapidly by more than 90 %. An economic process able to offset these fluctuations has to take unconventional methods into account beside well-known strategies like acid/basic leaching or solvent extraction. The solid-state chlorination provides such an unconventional method for mobilizing RE elements from waste streams. Instead of hydrochloric acid this kind of chlorination decomposes NH4Cl thermally to release up to 400 °C hot HCl gas. After cooling the resulting solid metal chlorides may be easily dissolved in pH-adjusted water. Without producing strongly acidic wastes and with NH4Cl as cheap source for hydrogen chloride, solid-state chlorination provides various advantages in terms of costs and disposal. In the course of the SepSELSA project this method was examined, adjusted and optimized for RE recycling from fluorescent lamp scraps as well as Fe14Nd2B magnets. Thereby many surprising influences and trends required various analytic methods to examine the reasons and special mechanisms behind them.

  1. Magnetic Partitioning Nanofluid for Rare Earth Extraction from Geothermal Fluids

    McGrail, Bernard P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Jian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Rare earth metals are critical materials in a wide variety of applications in generating and storing renewable energy and in designing more energy efficient devices. Extracting rare earth metals from geothermal brines is a very challenging problem due to the low concentrations of these elements and engineering challenges with traditional chemical separations methods involving packed sorbent beds or membranes that would impede large volumetric flow rates of geothermal fluids transitioning through the plant. We are demonstrating a simple and highly cost-effective nanofluid-based method for extracting rare earth metals from geothermal brines. Core-shell composite nanoparticles are produced that contain a magnetic iron oxide core surrounded by a shell made of silica or metal-organic framework (MOF) sorbent functionalized with chelating ligands selective for the rare earth elements. By introducing the nanoparticles at low concentration (≈0.05 wt%) into the geothermal brine after it passes through the plant heat exchanger, the brine is exposed to a very high concentration of chelating sites on the nanoparticles without need to pass through a large and costly traditional packed bed or membrane system where pressure drop and parasitic pumping power losses are significant issues. Instead, after a short residence time flowing with the brine, the particles are effectively separated out with an electromagnet and standard extraction methods are then applied to strip the rare earth metals from the nanoparticles, which are then recycled back to the geothermal plant. Recovery efficiency for the rare earths at ppm level has now been measured for both silica and MOF sorbents functionalized with a variety of chelating ligands. A detailed preliminary techno-economic performance analysis of extraction systems using both sorbents showed potential to generate a promising internal rate of return (IRR) up to 20%.

  2. Rare-earth metal prices in the USA ca. 1960 to 1994

    Hedrick, James B.


    Rare-earth metal prices were compiled from the late 1950s and early 1960s through 1994. Although commercial demand for rare-earth metals began in 1908, as the alloy mischmetal, commercial quantities of a wide range of individual rare-earth metals were not available until the late 1950s. The discovery of a large, high-grade rare-earth deposit at Mountain Pass. CA, USA, in 1949, was significant because it led to the production of commercial quantities or rare-earth elements that reduced prices and encouraged wider application of the materials. The availability of ore from Mountain Pass, and other large rare-earth deposits, especially those in Australia and China, has provided the world with abundant resources for rare-earth metal production. This availability, coupled with improved technology from Government and private-sector metallurgical research, has resulted in substantial decreases in rare-earth metal prices since the late 1950s and early 1960s. Price series for the individual rare-earth metals (except promethium) are quoted on a kilogram basis from the late 1950s and early 1960s through 1994. Prices are given in US dollars on an actual and constant dollar basis. Industrial and economic factors affecting prices during this time period are examined.

  3. Leaching behaviors of iron and aluminum elements of ion-absorbed-rare-earth ore with a new impurity depressant%离子型稀土矿中铝铁杂质的浸出与抑制规律

    邱廷省; 方夕辉; 伍红强; 曾清华; 朱冬梅


    通过红外光光谱测定、XRD检测等测试方法分析了稀土矿浸出过程中各种矿物表面性质的变化,稀土离子及铝、铁杂质离子与浸出剂和抑制剂的浸出交换过程及规律。结果表明,抑制剂的添加会与稀土矿中的铝、铁等杂质离子反应,形成化合物,从而降低浸出母液中铝、铁杂质离子含量,但不会影响离子型稀土的交换浸出过程。在机理分析的基础上,采用对铝铁杂质有高效抑制效果的抑杂剂LG-01进行离子型稀土矿抑制铝铁杂质的浸出实验研究。结果表明,在不影响离子型稀土矿稀土离子浸出率的情况下,LG-01能有效降低离子型稀土矿浸出母液中铝、铁等杂质离子含量,去除率可达92%。%Ion-absorbed rare-earth ore is an important mineral resource which is widely extracted by in-situ leaching process. And such process generates a significant amount of impurities such as aluminum and iron ions in leaching solution simultaneously. The surface characteristics and interactions by infrared spectroscopy and X-ray diffraction were studied to optimize the leaching conditions. It is found that the environment-friendly depressant LG-01 can react with the impurity ions through the formation of a new complex on the surface of leaching residues. Thus, it reduces significantly the concentration of impurity ions in leaching solution and improves the leaching rate of rare-earth ore. Moreover, a leaching rate of 95.6%and an impurity removal rate of 92%have been achieved under the optimized conditions.

  4. Corrosion behavior of novel colour-stable imitation gold copper alloy with rare earth%抗变色仿金稀土铜合金的耐蚀行为

    罗利阳; 朱安印; 陈景林; 李周; 梁军; 张晓男


    A novel colour-stable imitation gold copper alloy with rare earth was designed and prepared. The microstructures, anti-tarnishing and corrosion resistance properties of the designed alloy and the existing mint metal of H72-1-1 were compared by means of metallographic analysis, neutral salt spray test, mass loss measurement, electrochemical impedance spectroscopy and scanning electron microscopy. The results show that the annealed microstructure of the designed alloy is fine and homogeneous, and discoloring time of the alloy in 3.5% NaCl solution is 25% longer than that of H72-1-1 alloy. The mass loss rate of the designed alloy is slightly lower than that of the H72-1-1 alloy in 3.5% NaCl solution, which can be attributed to the uniform and compact corrosion film which retards the corrosion process, and the corrosion rate is 10.3 μm/a. The charge transfer resistance Rct and the diffusion impedance Zw of the designed alloy increase much more greatly than those of the H72-1-1 alloy, which increases the corrosion process resistance.%设计并制备一种新型的抗变色仿金稀土铜合金.采用金相组织分析、中性盐雾试验、质量损失法、电化学阻抗谱和扫描电镜等手段对比研究所设计合金与现有造币用H72-1-1合金的组织结构、抗变色性能和耐蚀性能.结果表明:所设计合金退火组织细小、均匀,在3.5%NaCl溶液中保持不变色的时间较H72-1-1合金的延长了25%.在3.5%NaCl溶液中浸泡腐蚀过程中,所设计合金形成了一层均匀致密、完整的腐蚀产物膜,减缓了腐蚀的进程,其耐腐蚀性能优于H72-1-1合金的,腐蚀速率为10.3 μm/a;所设计合金电荷转移电阻Rct Warburg扩散阻抗Zw与H72-1-1合金的相比都有大幅度的提高,腐蚀过程阻力增加.

  5. Rare Earths; The Fraternal Fifteen (Rev.)

    Gschneidner, Jr., Karl A. [Iowa State University; Ames Laboratory


    Rare earths are a set of 15 elements: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. They are not rare and not earths; they are metals and quite abundant. They are studied to develop commercial products which are beneficial to mankind, and because some rare earths are important to fission products.

  6. Rare earth elements and strategic mineral policy

    Kooroshy, J.; Korteweg, R.; Ridder, M. de


    Newspapers report almost daily on international tensions around ‘strategic’ or ‘critical’ minerals such as rare earth elements. The temporary freeze of rare earth exports from China to Japan in late 2010 in retaliation of the capture of a Chinese captain is but one example of the strategic use of no

  7. Chinalco Rare Earth has Surpassed Ganzhou to Become the Biggest Giant in South China Rare Earth


    As the pillar enterprise in Chinalco rare earth unit,Chinalco Guangxi Rare Earth Company firmly grasped the historical opportunity of the state government supporting six big groups including Chinalco to integrate and develop domestic rare earth enterprises,riding the east wind to stand out,recently,it made significant

  8. Rare Earth Metals: Resourcefulness and Recovery

    Wang, Shijie


    When we appreciate the digital revolution carried over from the twentieth century with mobile communication and the Internet, and when we enjoy our high-tech lifestyle filled with iDevices, hybrid cars, wind turbines, and solar cells in this new century, we should also appreciate that all of these advanced products depend on rare earth metals to function. Although there are only 136,000 tons of annual worldwide demand, (Cho, Rare Earth Metals, Will We Have Enough?)1 rare earth metals are becoming such hot commodities on international markets, due to not only to their increasing uses, including in most critical military hardware, but also to Chinese growth, which accounts for 95% of global rare earth metal production. Hence, the 2013 technical calendar topic, planned by the TMS/Hydrometallurgy and Electrometallurgy Committee, is particularly relevant, with four articles (including this commentary) contributed to the JOM October Issue discussing rare earth metals' resourcefulness and recovery.

  9. Alloy softening in binary iron solid solutions

    Stephens, J. R.; Witzke, W. R.


    An investigation was conducted to determine softening and hardening behavior in 19 binary iron-alloy systems. Microhardness tests were conducted at four temperatures in the range 77 to 411 K. Alloy softening was exhibited by 17 of the 19 alloy systems. Alloy softening observed in 15 of the alloy systems was attributed to an intrinsic mechanism, believed to be lowering of the Peierls (lattice friction) stress. Softening and hardening rates could be correlated with the atomic radius ratio of solute to iron. Softening observed in two other systems was attributed to an extrinsic mechanism, believed to be associated with scavenging of interstitial impurities.

  10. Global rare earth resources and scenarios of future rare earth industry

    CHEN Zhanheng


    It is known to all that China is abundant in rare earth resources. But rare earth deposits are really not that rare in the earth crust. In the five continents, i.e. Asia, Europe, Australia, North and South America, and Africa, there are about thirty four countries found to have rare earth deposits; Brazil might surpass China and rank the first in rare earth deposits. At present, investment in rare earth production was surged,there have been about 200 projects, and the total production for 25 of them would be more than 170 thousand tons after 2015, a multi-supply system on rare earths is being established worldwide. Cautions on the investment of rare earth production are involved.

  11. Solar Energy Cell with Rare Earth Film

    Li Baojun; Yang Tao; Zhou Yao; Zhou Meng; Fu Xiliang; Fu Li


    The characteristic of the solar energy cell with the rare earth film according to theory of molecular structure was introduced.When sunlight shines, the molecules of the rare earth film can absorb energy of the photon and jump to the excited state from the basic state, and play a role in storing solar energy.When sunlight do not shine, the electron of the excited state returns to the basic state, the rare earth film can automatically give out light and shine to surface of the solar cell, which can make solar cell continuously generate electric current.The rare earth film can absorb direct,scattering sunlight, and increase density of solar energy to reach surface of the solar cell, and play focusing function.The rare earth film can bear 350 ~ 500 ℃, which make the solar cell be able to utilize the focusing function system.Because after luminescence of the rare earth film, it can release again the absorbed solar energy through 1 ~ 8 h, and play a role in storing solar energy; The solar cell with the rare-earth film can generate electricity during night and cloudy days, and remarkably increase efficiency of the solar cell.

  12. Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel



    The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.

  13. Structural and electronic properties of binary amorphous aluminum alloys with transition metals and rare earth metals; Strukturelle und elektronische Eigenschaften binaerer amorpher Aluminiumlegierungen mit Uebergangsmetallen und Metallen der Seltenen Erden

    Stiehler, Martin


    The influence of the d-states of the transition metals on the structure formation in amorphous alloys has so far only been inadequately understood. The present work aims to elaborate additional contributions to the understanding of binary amorphous aluminum alloys with transition metals. Special emphasis was placed on alloys with a subgroup of the transition metals, the rare earth metals. Within the scope of the present work, layers of Al-Ce in the region of 15at% Ce-80at% Ce were produced by sequential flash evaporation at 4.2K in the high vacuum, and characterized electronically by electrical resistance and Hall effect measurements as well as structurally by transmission electron diffraction. In addition, studies of plasma resonance were carried out by means of electron energy loss spectroscopy. In the range of 25at% Ce-60at% Ce, homogeneous amorphous samples were obtained. Especially the structural investigations were made difficult by oxidation of the material. The influence of the Ce-4f electrons manifests itself mainly in the low-temperature and magnetoresistance, both of which are dominated by the Kondo effect. The Hall effect in Al-Ce is dominated by anomalous components over the entire temperature range (2K-320K), which are attributed to skew-scattering effects, also due to Ce-4f electrons. Down to 2K there was no macroscopic magnetic order. In the region 2K-20K, the existence of clusters of ordered magnetic moments is concluded. For T> 20K, paramagnetic behavior occurs. With regard to the structural and electronic properties, a-Al-Ce can be classified as a group with a-Al- (Sc, Y, La). In the sense of plasma resonance, a-Al-Ce is excellently arranged in a system known from other Al transition metal alloys. Furthermore, by increasing the results of binary amorphous Al transition metal alloys from the literature, it has been found that the structure formation in these systems is closely linked to a known but still unexplained structure-forming effect that

  14. Correlations in rare-earth transition-metal permanent magnets

    Skomski, R., E-mail:; Manchanda, P. [Department of Physics and Astronomy and NCMN, University of Nebraska, Lincoln, Nebraska 68508 (United States); Kashyap, A. [School of Basic Science, IIT Mandi, Mandi, Himachal Pradesh (India)


    It is investigated how electron-electron correlations affect the intrinsic properties of rare-earth transition-metal magnets. Focusing on orbital moment and anisotropy, we perform model calculations for 3d-4f alloys and density-functional theory (DFT) calculations for NdCo{sub 5}. On an independent-electron level, the use of a single Slater determinant with broken spin symmetry introduces Hund's rule correlations, which govern the behavior of rare-earth ions and of alloys described by the local spin density approximation (LSDA) and LSDA + U approximations to DFT. By contrast, rare-earth ions in intermetallics involve configuration interactions between two or more Slater determinants and lead to phenomena such as spin-charge distribution. Analyzing DFT as a Legendre transformation and using Bethe's crystal-field theory, we show that the corresponding density functionals are very different from familiar LSDA-type expressions and outline the effect of spin-charge separation on the magnetocrystalline anisotropy.

  15. Method for determination of small amounts of rare earths and thorium in phosphate rocks

    Waring, C.L.; Mela, H.


    In laboratory investigations, interest developed in the possible rare-earth content of phosphate samples from Florida and the northwestern United States. Because of the difficulty of making chemical determinations of traces of individual rare earths, a combined chemical-spectrographic method was investigated. After removal of iron by the extraction of the chloride with ether, the rare earths and thorium are concentrated by double oxalate precipitation, using calcium as a carrier. The rare earths are freed from calcium by an ammonium hydroxide precipitation with a fixed amount of aluminum as a carrier. The aluminum also serves as an internal standard in the final spectrographic analysis. The method will determine from 0.02 to 2 mg. of each rare earth with an error no greater than 10%. The investigation has resulted in a fairly rapid and precise procedure, involving no special spectrographic setup. The method could be applied to other types of geologic materials with the same expected accuracy.

  16. Environmental Defects And Economic Impact On Global Market Of Rare Earth Metals

    Charalampides, G.; Vatalis, K.; Karayannis, V.; Baklavaridis, A.


    Rare earth elements include the 14 lanthanides as well as lanthanium and often yttrium. Actually, most of them are not very rare and occur widely dispersed in a variety of rocks. Rare earth metals are vital to some of the world's faster growing industries: catalysts, Nd-magnets, ceramics, glass, metallurgy, battery alloys, electronics and phosphors. Worldwide, the main countries for distribution of rare earths deposits include China, USA, Russia, Brasil, India, Australia, Greenland and Malaysia. The mining and processing of rare earth metals usually result in significant environmental defects. Many deposits are associated with high concentrations of radioactive elements such as uranium and thorium, which requires separate treatment and disposal. The accumulation of rare earth elements in soils has occurred due to pollution caused by the exploitation of rare earth resources and the wide use of rare earths as fertilizers in agriculture. This accumulation has a toxic effect on the soil microfauna community. However, there are large differences in market prices due to the degree of purity determined by the specifications in the applications. The main focus of this article is to overview Rare Earth Metals’ overall impact on global economy and their environmental defects on soils during processing techniques and as they are used as fertilizers.

  17. Rare earth elements in Hamersley BIF minerals

    Alibert, Chantal


    Minerals from the Hamersley banded iron formation, Western Australia, were analyzed for Y and rare earth elements (YREEs) by laser ablation ICP-MS to investigate diagenetic pathways, from precursor phases to BIF minerals. One group of apatites carries the seawater REE signature, giving evidence that P and REEs, thoroughly scavenged from the water column by Si-ferrihydrite particles, were released upon microbial Fe3+ reductive dissolution of Si-ferrihydrite in pore-water and finally sequestered mainly in authigenic apatite. The absence of fractionation between apatite and seawater suggests that REE were first incorporated into an amorphous calcium phosphate as fully hydrated cations, i.e. as outer-sphere complexes. The iron oxides and carbonates carry only a small fraction of the whole-rock REE budget. Their REE patterns are distinctly enriched in Yb and show some M-type tetrad effect consistent with experimental Kd(REE) between solid and saline solution with low carbonate ion concentrations. It is deduced that hematite formed at an incipient stage of Fe2+-catalyzed dissolution of Si-ferrihydrite, via a dissolution-reprecipitation pathway. The REE pattern of greenalite, found as sub-micron particles in quartz in a chert-siderite sample, is consistent with its authigenic origin by precipitation in pore-water after dissolution of a small amount of Si-ferrihydrite. Magnetite carries very low YREEs (ppb-level), has an homogeneous pattern distinctly enriched in the mid-REEs compared to hematite, and includes a late population depleted in light-REEs, Ba and As. Magnetite forming aggregates and massive laminae is tentatively interpreted as reflecting some fluid-aided hematite-magnetite re-equilibration or transformation at low-grade metamorphic temperatures.

  18. International strategic minerals inventory summary report; rare-earth oxides

    Jackson, W.D.; Christiansen, Grey


    Bastnaesite, monazite, and xenotime are currently the most important rare-earth minerals. Bastnaesite occurs as a primary mineral in carbonatites. Monazite and xenotime also can be found in primary deposits but are recovered principally from heavy-mineral placers that are mined for titanium or tin. Each of these minerals has a different composition of the 15 rare-earth elements. World resources of economically exploitable rare-earth oxides (REO) are estimated at 93.4 million metric tons in place, composed of 93 percent in primary deposits and 7 percent in placers. The average mineral composition is 83 percent bastnaesite, 13 percent monazite, and 4 percent of 10 other minerals. Annual global production is about 67,000 metric tons of which 41 percent is from placers and 59 percent is from primary deposits; mining methods consist of open pits (94 percent) and dredging (6 percent). This output could be doubled if the operations that do not currently recover rare earths would do so. Resources are more than sufficient to meet the demand for the predictable future. About 52 percent of the world's REO resources are located in China. Ranking of other countries is as follows: Namibia (22 percent), the United States (15 percent), Australia (6 percent), and India (3 percent); the remainder is in several other countries. Conversely, 38 percent of the production is in China, 33 percent in the United States, 12 percent in Australia, and 5 percent each in Malaysia and India. Several other countries, including Brazil, Canada, South Africa, Sri Lanka, and Thailand, make up the remainder. Markets for rare earths are mainly in the metallurgical, magnet, ceramic, electronic, chemical, and optical industries. Rare earths improve the physical and rolling properties of iron and steel and add corrosion resistance and strength to structural members at high temperatures. Samarium and neodymium are used in lightweight, powerful magnets for electric motors. Cerium and yttrium increase the

  19. Rare earth elements in nuclear medicine

    Kodina G.E.; Kulakov V.N.; Sheino I.N.


    The review focuses on the key applications of stable and radioactive isotopes of rare earth elements in the technology of nuclear medicine, radionuclide diagnostics and therapy, as well as magnetic resonance imaging and binary radiotherapy technologies.

  20. Rare earth elements in nuclear medicine

    Kodina G.E.


    Full Text Available The review focuses on the key applications of stable and radioactive isotopes of rare earth elements in the technology of nuclear medicine, radionuclide diagnostics and therapy, as well as magnetic resonance imaging and binary radiotherapy technologies.

  1. Rare earth element mines, deposits, and occurrences

    U.S. Geological Survey, Department of the Interior — This dataset contains location, geologic and mineral economic data for world rare earth mines, deposits, and occurrences. The data in this compilation were derived...

  2. Rare Earth: Production, Trade and Demand

    HONG Feng


    @@ Editor's note: The paper was quoted from the papers collection of the "19th International Workshop on Rare Earth Permanent Magnets & Their Applications", held in Beijing on August 30-Spetember 2 of 2006.

  3. China Not the Only Rare Earth Exporter


    Since China announced it was reducing exports of rare earth,there have been continuous voices in the international community demanding China expand exports or seek alternative resources. The United States has also complained to the WTO that China is hoarding the commodity. Subjected to scathing censure,what difficulties are facing China’s rare earth industry? When other countries seek alternative resources,how is the Chinese rare earth market affected? Economy&Nation Weekly,Xinhua News Agency’s finance magazine,recently interviewed Lin Donglu,Secretary General of the Chinese Society of Rare Earths,and Wang Hongqian, General Manager of China Non-Ferrous Metal Industry’s Foreign Engineering and Construction Co.Ltd.Edited excerpts follow

  4. Electronic Structure of Rare-Earth Metals. II. Positron Annihilation

    Williams, R. W.; Mackintosh, Allan


    The angular correlation of the photons emitted when positrons annihilate with electrons has been studied in single crystals of the rare-earth metals Y, Gd, Tb, Dy, Ho, and Er, and in a single crystal of an equiatomic alloy of Ho and Er. A comparison of the results for Y with the calculations...... of Loucks shows that the independent-particle model gives a good first approximation to the angular distribution, although correlation effects probably smear out some of the structure. The angular distributions from the heavy rare-earth metals are very similar to that from Y and can be understood...... qualitatively in terms of the relativistic augmented-plane-wave calculations by Keeton and Loucks. The angular distributions in the c direction in the paramagnetic phases are characterized by a rapid drop at low angles followed by a hump, and these features are associated with rather flat regions of Fermi...

  5. Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

    Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.


    A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

  6. 2004 Top 10 Chinese Rare Earth Events


    1. Management to the Investment in Rare Earth IndustryConfirmedIn July 2004, "Decision on the Reform in Investment System" was formally publicized by the State Council of the People's Republic of China. The fifth item in the Decision stipulates that ore exploitation, smelting & separation and rare earth deep-processed projects with total investment over RMB¥100 million should be approved by the investment governing department of the State Council, and that other

  7. 12 Ministries Control Rare Earth Exports


    <正>"It is very natural to reserve rare earth as a strategic resource.Many countries do this,including China."On April 8,Sun Lihui,Vice Director of Metal Section of Chemicals Import & Export Commerce Chamber of China Minmetals Corporation told a reporter that as early as 2006,China has launched a strategic plan for rare earth,"but it was interrupted by the subsequent financial crisis."

  8. Ternary rare earth-lanthanide sulfides

    Takeshita, Takuo; Gschneidner, Jr., Karl A.; Beaudry, Bernard J.


    A new ternary rare earth sulfur compound having the formula: La.sub.3-x M.sub.x S.sub.4 where M is a rare earth element selected from the group europium, samarium and ytterbium and x=0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to C.

  9. Partitioning properties of rare earth ores in China

    CHI Ru'an; LI Zhongjun; PENG Cui; ZHU Guocai; XU Shengming


    The properties of rare earth partitioning in Chinese industrial rare earth ores were analyzed. Rare earth ores can be divided into the single-mineral type ore with bastnaesite, the multi-mineral type ore with bastnaesite and monazite, and the weathering crust type. Both the Bayan Obo rare earth ore and the Zhushan rare earth ore are a kind of mixed ore, consisting of bastnaesite and monazite. Their rare earth partitionings are strongly enriched in light rare earths, where CeO2 is 50% and the light rare earth partitioning is totally over 95%. The Mianning rare earth ore as well as the Weishan rare earth is a kind of rare earth ore only having bastnaesite. Their rare earth partitionings are also strongly enriched in light rare earths,in which CeO2 is 47% and the light rare earth partitioning is totally over 94%. For the weathering crust type rare earth ore,there are the Longnan rare earth ore, the Xunwu rare earth ore, and the middle yttrium and rich europium ore. In the Longnan rare earth ore, which is strongly enriched in heavy rare earths, Y2O3 is 64.83%, and the heavy and light rare earth partitionings are 89.40% and 10.53%, respectively. In the Xunwu rare earth ore, which is strongly enriched in light rare earths, CeO2 is 47.16%, and the light rare earth partitioning is totally 93.25%. Y and Eu are enriched in the middle yttrium and rich europium ore. Its middle rare earth partitioning is totally over 10%, and Eu2O3 and Y2O3 are over 0.5% and 20%,respectively, which are mainly industrial resources of the middle and the heavy rare earths.

  10. Evaluation of Anti-fouling Performance for Rare-earth Alloy Water Treatmenter%稀土合金水处理器阻垢性能评价实验研究

    孙灵芳; 姜德峰; 张冬生; 张艳辉; 曹生现


    he antifouling performance of the new Rare-earth Alloy Nanometer Water Treatment (RANWT) is evaluatedby circulating cooling water fouling dynamic simulator. The Experimental conditions: inlet water temperatureof 28.5 ± 0.5 ℃, water bath temperature of 50 ±0.3 ℃, flow rate of 0.4 m. s^(-1) and water hard- ness 1 400.0 mg. L^(-1) ( CaCO3 ). The five groups experiment data were tested on test loop and reference loop and the monitoring parameters include fouling resistance, pH, conductivity and turbidity etc. The results showed that :water treatment average anti-fouling efficiency is 86.4% in high hardness conditions, that the scale inhibition effect of water treatment is better. This water treatment can effect water quality parameter based on analyzing multiple the water quality parameter curves and fouling resistance curves.%为考察新型稀土合金水处理器(下称阻垢器)阻垢性能,本文利用循环冷却水污垢动态模拟试验台,对阻垢器性能进行动态评价实验。在相同实验条件下(入口水温28.5±0.5℃,水浴温度50±0.5℃,流速0.40 m.s-1,水质硬度1 400.0 mg.L-1),对加装阻垢器和未加装阻垢器两路水质进行动态实验,连续监测污垢热阻和水质参数(包括电导率、pH和浊度等),进行了5组重复性实验。结果表明:稀土合金水处理器对高硬度水质平均阻垢率达81.6%,抑垢效果较好,从实验水质参数变化和换热器表面积垢状态观察,该阻垢器对水质浊度、电导率、pH等参数有一定影响。

  11. Production technique of vermicular graphite iron cylinder head of vehicle diesel engine

    Zhou Gen; Liu Wanhua


    The 25 years' production and application have proved that vermicular graphite iron cylinder heads with vermicularity ≥50% satisfy the machinability and performance demand of diesel engine. The method, in which using cupola-induction furnace duplex melting and pour-over process with rare earth-ferrosilicon or rare earth silicon compound as vermicularizing alloy plus rare earth-magnesium-ferrosilicon as stirring alloy, is an optimal verroicularizing process for obtaining satisfied vermicularity. Using top kiss risers, enlarging kissing areas and expanding covering width and making ingates to freeze eadier are the effective measures to eliminate shrinkage, blowhole and oxide inclusions in the vermicular graphite iron cylinder heads.

  12. Anisotropy of rare-earth magnets

    R.Skomski; D.J.Sellmyer


    Rare-earth intermetallics such as Nd2FeI4B and Sm-Co are widely used as high-performance permanent magnets,because they combine high magnetocrystalline anisotropy with reasonable magnetization and Curie temperature.The anisotropy is a combined effect of spin-orbit coupling and electrostatic crystal-field interactions.The main contribution comes from the rare-earth 4f electrons,which are well-screened from the crystalline environment but exhibit a strong spin-orbit coupling.In this limit,the magnetocrystalline anisotropy has a very transparent physical interpretation,the anisotropy energy essentially being equal to the energy of Hund's-rules 4f ion in the crystal field.The corresponding expression for the lowest-order uniaxial anisotropy constant K1 is used to discuss rare-earth substitutions,which have recently attracted renewed interest due to shifts in the rare-earth production and demand.Specific phenomena reviewed in this article are the enhancement of the anisotropy of Sm2Fe17 due to interstitial nitrogen,the use of Sm-Co magnets for high-temperature applications,and the comparison of rare-earth single-ion anisotropy with other single-ion and two-ion mechanisms.

  13. Rare earth elements and permanent magnets (invited)

    Dent, Peter C.


    Rare earth (RE) magnets have become virtually indispensible in a wide variety of industries such as aerospace, automotive, electronics, medical, and military. RE elements are essential ingredients in these high performance magnets based on intermetallic compounds RECo5, RE2TM17 (TM: transition metal), and RE2TM14B. Rare earth magnets are known for their superior magnetic properties—high induction, and coercive force. These properties arise due to the extremely high magnetocrystalline anisotropy made possible by unique 3d-4f interactions between transition metals and rare earths. For more than 40 years, these magnets remain the number one choice in applications that require high magnetic fields in extreme operating conditions—high demagnetization forces and high temperature. EEC produces and specializes in RECo5 and RE2TM17 type sintered magnets. Samarium and gadolinium are key RE ingredients in the powder metallurgical magnet production processes which include melting, crushing, jet milling, pressing, sintering, and heat treating. The magnetic properties and applications of these magnets will be discussed. We will also briefly discuss the past, current, and future of the permanent magnet business. Currently, over 95% of all pure rare earth oxides are sourced from China, which currently controls the market. We will provide insights regarding current and potential new magnet technologies and designer choices, which may mitigate rare earth supply chain issues now and into the future.


    赵虎; 杨秦莉; 冯鹏发; 刘仁智; 付静波


    试验研究了掺杂LaO3、Y2 O3、CeO2稀土氧化物颗粒对钼合金的粉末物性、烧结进程、制品的烧结致密度及压力加工丝材的室温力学性能的影响规律.试验结果表明,掺杂稀土氧化物粒子细化了钼粉的粒度,降低了松装密度和粒度分布范围,同时导致粉末团聚现象增多;稀土氧化物粒子延迟了钼合金的烧结进程,降低了烧结制品的致密度,同时细化了烧结体晶粒尺寸.稀土氧化物粒子以弥散强化和细晶强化的形式,提高了钼合金丝的室温强度.CeO2显著提高了钼合金丝的室温韧性,La203、Y2O3则降低了钼合金丝的室温韧性.%The effects on the molybdenum alloy powder properties,sintering proceeding and sintering products density and mechanical properties of molybdenum alloy as-worked wire which was doped with rare-earth oxides particles such as La2O3 、Y2O3 、CeO2 were studied.The results showed that the particles size of the molybdenum alloy powder were refined,loose density and particle size distribution were reduced by doping rare-earth oxides particles,though at the same time molybdenum alloy powder aggregation were increased.Sintering proceeding was delayed,sintering products density was reduced and the grain size was refined by the rare-earth oxides particles during sintering process.The room temperature strength of the molybdenum alloy wire as-worked was increased by the grain refinement strengthening and dispersion strengthening of the doped rare-earth oxides particles.Room temperature toughness of molybdenum alloy wire as-worked was greatly improved as doped CeO2 particles but reduced as doped La2O3 and Y2O3 particles.

  15. 钢丝热镀锌-10%铝-混合稀土合金镀层工艺%Process for hot-dip galvanizing zinc-10%aluminum-mixed rare earth alloy on steel wires

    裘海锋; 王英民; 苗立贤; 侯志娇; 苗瀛; 杨冰


    A process for hot-dip galvanizing Zn-10%Al-mixed rare earth alloy coating on steel wires based on the principle of electrodeposition (i.e. electroplating a Zn coating prior to galvanizing) was developed as a substitute to common double-dip galvanizing method. The bath composition and operation conditions of individual procedure were presented. It is stressed that the pretreatment of steel wire is the key point. Electrolytic degreasing twice, quartz sand rubbing, and overflow rinsing are employed to produce clean steel wire surface and ensure the quality of coating. The temperature range of molten alloy (455-460 °C) and other technical key points such as the nitrogen wiping temperature were given. The process has advantages of energy saving and low cost as compared with the double-dip method. The causes for the formation of floating aluminum-rich product which influences the coating quality and its treatment method for making the coating smooth and free of defects such as lumps and bumps were discussed. The surface quality of steel wires obtained by the process is stable, and the technical and physicochemical indexes meet the requirements of the standard YB/T 4221-2010 Coated Steel Wire for Machine Woven Steel Wire Mesh.%利用电沉积原理,提出了一种在钢丝表面热浸镀锌-10%铝-稀土合金镀层的工艺,在热浸镀合金之前电沉积一层锌镀层,以代替普通的“双镀法”。给出了各工序的溶液配方及工艺条件。指出重点应放在钢丝的预处理上。采用2道电解脱脂以及石英砂擦拭、水溢流漂洗工艺,得到非常清洁的钢丝表面,才能保证镀层质量。给出了合金液温度范围(455~460°C)、氮气抹拭温度参数等技术要点。该工艺较“双镀法”节约能源,生产成本低。探讨了影响镀层质量的富集铝漂浮物的产生原因及处理办法,使镀层光滑,无“疙瘩”等缺陷。该工艺所得钢丝的表面质量

  16. Recovery of rare earths from acid leach solutions of spent nickel-metal hydride batteries using solvent extraction

    夏允; 肖连生; 田吉英; 李兆洋; 曾理


    The extraction of rare earths from acid leach solutions of spent nickel-metal hydride batteries using a primary amine ex-tractant of N1923 was studied. The effects of feed pH, temperature, agitation rate and time on the extraction of rare earths, as well as stripping agent composition and concentration, phase ratio on the stripping were investigated. In addition, the extraction isotherm was determined. The pilot plant test results showed that the extraction of rare earths reached 99.98% after a five-stage counter current ex-traction. The mixed rare earths oxalates with the 99.77% purity of rare earth elements and impurity content less than 0.05% were ob-tained by the addition of oxalic acids in loaded strip liquors. The extractant exhibited good selectivity of rare earths over base metals of iron, nickel, copper and manganese.

  17. 2011 Review and outlook of China rare earth market

    Zhang Lihua; Bai Jinlong


    In 2011, the start year of the "Twelfth-Five Year Plan" program, a series of policies were issued targeting on rare earth industry. Price of rare earths fluctuated sharply during 2011 and consumers were concerned about the supply of rare earth. There was a big change in rare earth industry.

  18. 2007 China Rare Earths Import & Export Analysis and Suggestions (continued)

    Yin Jianhua; Zuo Xichao


    @@ 4. Increasing import of rare earth resources products As a big producer and an important export country of rare earth products for years, rare earths import is in an auxiliary position in China. import volume is rather small. However, since the strengthened macro control measures and restriction of mining scale in 2007, domestic rare earth supply was tight in China.

  19. Prices of Rare Earth Products Tend to Rise(Continued)


    8. Ji Daiyu, General Manager of Baotou Xinyuan RareEarth Hi-Tech Materials Co. LtdControl gross to stabilize prices. Chinese rare earth is precious strategic resource. The more it is exploit, the less it will be. The State has put forward rare earth policy of "strengthen management, protect resource, develop scientifically and face international". Chinese rare earth

  20. Preparation and characterization of zirconium dioxide catalyst supports modified with rare earth elements

    Ozawa, Masakuni; Kimura, Mareo (Toyota Central Research and Development Labs., Inc., Aichi (Japan))


    ZrO{sub 2} catlyst supports modified with rare earth elements were prepared by coprecipitation from an aqueous solution of zirconium oxychloride and rare earth chlorides. The crystallization of amorphous hydrous ZrO{sub 2} was inhibited by doping with rare earths; the crystallization temperature was elevated as the amount and ionic radius of the rare earth modifiers was increased. Only modification using cerium had no effect on the crystallization process. The behavior of cerium was different from that of other rare earth elements with valency +3. A metastable cubic phase was formed for ZrO{sub 2} modified with 10 mol.% lanthanum, neodymium and samarium by heating at 600degC. X-ray diffraction and Raman data indicated that the metastable phase had large microstrain and short-range ordering similar to tetragonal symmetry. Rare earth modified ZrO{sub 2} showed a large surface area and good thermal stability as a catalyst support. The carbon monoxide oxidation activity of iron was enhanced by modification with neodymium of ZrO{sub 2} supports. The results suggest the effectiveness of rare earth modified ZrO{sub 2} as catalyst supports. (orig.).

  1. Complex rare-earth aluminum hydrides: mechanochemical preparation, crystal structure and potential for hydrogen storage.

    Weidenthaler, Claudia; Pommerin, André; Felderhoff, Michael; Sun, Wenhao; Wolverton, Christopher; Bogdanović, Borislav; Schüth, Ferdi


    A novel type of complex rare-earth aluminum hydride was prepared by mechanochemical preparation. The crystal structure of the REAlH(6) (with RE = La, Ce, Pr, Nd) compounds was calculated by DFT methods and confirmed by preliminary structure refinements. The trigonal crystal structure consists of isolated [AlH(6)](3-) octahedra bridged via [12] coordinated RE cations. The investigation of the rare-earth aluminum hydrides during thermolysis shows a decrease of thermal stability with increasing atomic number of the RE element. Rare-earth hydrides (REH(x)) are formed as primary dehydrogenation products; the final products are RE-aluminum alloys. The calculated decomposition enthalpies of the rare-earth aluminum hydrides are at the lower end for reversible hydrogenation under moderate conditions. Even though these materials may require somewhat higher pressures and/or lower temperatures for rehydrogenation, they are interesting examples of low-temperature metal hydrides for which reversibility might be reached.

  2. Effect of Rare Earth on Microstructure of γ-TiAl Intermetallics

    孔凡涛; 陈子勇; 田竞; 陈玉勇; 贾均


    The rare earth (RE) elements (Ce, La) were added to binary Ti-47% Al alloys (atomic fraction) by Induction Skull Melting. The element Ce of 1.0 atomic percent was added individually, and La of 0.2 atomic percent was added individually. This article studied the influences of rare earth metal (Ce, La) on microstructure of as-cast TiAl based alloy by XRD, SEM, EMPA and TEM measurement methodology. The results show that most of rare earth-rich phases (AlCe, AlLa) are uniformly distributed in grain boundary in the shape of discontinuous network, and some particles of rare earth-rich phases within the grains are mainly ellipsoids. In addition, rare earth element can obviously refine the grain size and the lamellar thickness of as-cast TiAl based alloy samples. The grain size of Ti-47Al-1.0Ce-0.2La alloy reaches about 30~80 μm, and the lamellar thickness of its γ phase and α2 phase are less than 200 and 20 nm, respectively.

  3. China Not the Only Rare Earth Exporter


    @@ Since China announced it was reducing exports of rare earth,there have been continuous voices in the international community demanding China expand exports or seek alternative resources.The United States has also complained to the WTO that China is hoarding the commodity.

  4. Replacing the Rare Earth Intellectual Capital

    Gschneidner, Jr., Karl


    The rare earth crisis slowly evolved during a 10 to 15 year period beginning in the mid-1980s, when the Chinese began to export mixed rare earth concentrates. In the early 1990s, they started to move up the supply chain and began to export the individual rare earth oxides and metals. By the late 1990s the Chinese exported higher value products, such as magnets, phosphors, polishing compounds, catalysts; and in the 21st century they supplied finished products including electric motors, computers, batteries, liquid-crystal displays (LCDs), TVs and monitors, mobile phones, iPods and compact fluorescent lamp (CFL) light bulbs. As they moved to higher value products, the Chinese slowly drove the various industrial producers and commercial enterprises in the US, Europe and Japan out of business by manipulating the rare earth commodity prices. Because of this, the technically trained rare earth engineers and scientists who worked in areas from mining to separations, to processing to production, to manufacturing of semifinished and final products, were laid-off and moved to other fields or they retired. However, in the past year the Chinese have changed their philosophy of the 1970s and 1980s of forming a rare earth cartel to control the rare earth markets to one in which they will no longer supply the rest of the world (ROW) with their precious rare earths, but instead will use them internally to meet the growing demand as the Chinese standard of living increases. To this end, they have implemented and occasionally increased export restrictions and added an export tariff on many of the high demand rare earth elements. Now the ROW is quickly trying to start up rare earth mines, e.g. Molycorp Minerals in the US and Lynas Corp. in Australia, to cover this shortfall in the worldwide market, but it will take about five years for the supply to meet the demand, even as other mines in the ROW become productive. Unfortunately, today there is a serious lack of technically trained

  5. Orthodontic rare earth magnets--in vitro assessment of cytotoxicity.

    Bondemark, L; Kurol, J; Wennberg, A


    The aim of this study was to assess and compare in vitro the cytotoxic effects of uncoated and parylene-coated rare earth magnets, used in orthodontics. Cytotoxicity of samarium-cobalt magnets (SmCo5 and Sm2Co17) and neodymium-iron-boron magnets (Nd2Fe14B) was assessed by two in vitro methods, the millipore filter method and an extraction method. Orthodontic stainless steel brackets served as controls. Uncoated SmCo5-magnets showed high cytotoxicity while uncoated Sm2Co17-magnets demonstrated moderate cytotoxicity. Uncoated neodymium-iron-boron magnets, as well as parylene coated Sm2Co17-magnets and parylene-coated neodymium-iron-boron magnets, showed negligible cytotoxicity. Short-term exposure to a static magnetic field did not cause any cytotoxic effect on the cells.

  6. MBE growth and characterisation of light rare-earth superlattices

    Ward, R.C.C.; Wells, M.R.; Bryn-Jacobsen, C.


    The molecular beam epitaxy growth techniques which have already successfully produced a range of heavy rare-earth superlattices have now been extended to produce superlattices of two light rare-earth elements, Nd/Pr, as well as superlattices and alloy films of a heavy/light system, Ho/Pr. High......-resolution X-ray diffraction analysis shows the Nd/Pr superlattices to be of high structural quality, while the Ho/Pr superlattices are significantly less so. In the Ho/Pr superlattices, Pr is found to retain its bulk dhcp crystal structure even in thin layers (down to 6 atomic planes thick) sandwiched between...... thick layers of hcp Ho. In addition, neutron diffraction studies of the He/Pr superlattices have shown that the helical Ho magnetic order is not coherent through the dhcp Pr layers, in contrast to previous hcp/hcp superlattices Ho/Y, Ho/Lu and Ho/Er. The series of Ho:Pr alloy films has shown structural...

  7. Progress of Study on Application of Rare Earth Metals in Steels

    Wang Longmei; Lin Qin; Ji Jingwen; Lan Denian


    With the improvement of the clean steel by degrees, the functions of rare earth metals in steel are more focused on modification of inclusions and micro alloying.The new study concerning the application of RE metals in clean steels were investigated by ICP, metallographic examination, SEM, EDS, EPMA, TEM and IMMA.The mechanism of corrosion resistance in the weather resistance steel was clarified.The mechanism of abrasion resistance and the life of fatigue enhanced in the RE - heavy rails steel were discussed.Progress in study of application of rare earth metals in steels (including weather resistance steel, low alloy steel, and heavy rails steel) was covered in this paper.

  8. Effect of Rare Earths on Composition and Activities of Rare Earth Elements Binding Glycoprotein in Tea

    汪东风; 李俊; 赵贵文; 王常红; 魏正贵; 尹明


    The effects of spraying rare earths(RE) on composition and activities of tea polysaccharide were measured by inductively coupled plasma mass spectrometry (ICP-MS), gas chromatography(GC), amino acid analyzer and animal models. The results show that there are rare earth elements binding glycoprotein in tea (REE-TGP). The effects of RE on composition and content of saccharides in REE-TGP are not obvious. The contents of Hypro and Ser in REE-TGP are evidently enhanced in comparison with that in control (not treated with rare earth), but the content of Glu is smaller than that from control. The content of La in REE-TGP from the tea garden sprayed rare earth is 193% higher than that in control. REE-TGP declines content of blood sugar in mice and enhances immunization of rat, which are very evident when the animals are treated by REE-TGP from the tea garden sprayed RE.

  9. Report 1: International Cooperation to Development of Strategy and R&D Collaboration for Substitution of Rare Earth Resources and Report 2: Development of Magnetocaloric Alloys without Critical Elements

    Lee, Min Ha [Ames Laboratory (AMES), Ames, IA (United States); Ott, Ryan [Ames Laboratory (AMES), Ames, IA (United States)


    A Memorandum of Understanding was signed between the Ames Laboratory and Korea Institute of Industrial Technology (KITECH) in April of 2011 to establish a close cooperative relationship of research on Rare Metals. The Ames Laboratory through its operating contractor, Iowa State University, and the KITECH, as one of the goals of a joint Memorandum of Understanding, made agreement on a Cooperative Research and Development Agreement (CRADA) for a personnel exchange in April of 2012. Ames Laboratory and KITECH would be jointly performing collaboration work in this cooperation as the Parties. The individual backgrounds and capabilities of the Parties are ideally suited to the successful execution of this work. The Ames Laboratory has a history spanning more than 60 years of pioneering work in rare-earth (RE) research. With its team of internationally recognized rare-earth experts, the Ames Laboratory is uniquely positioned to provide the knowledge, expertise and training necessary to help ensure a global leadership position for the United States in rare-earth research, development and applications. The KITECH was founded to promote technological capability of small and medium-sized enterprises in Korea and has a mission of supporting research on materials science and engineering in Korea. In 2009, Korea Institute for Rare Metals (KIRAM) at KITECH was established. KIRAM makes selection and funding decisions for technology projects for strategic rare metals, and provides oversight of R&D programs. The KIRAM is focusing on the commercialization and recycling of particular rare metals. In addition KIRAM will be coordinating government, local universities, and small to medium enterprises to facilitate R&D support for core technologies. KIRAM will be carrying them through to commercialization, and establishing new industry.

  10. Report 1: International Cooperation to Development of Strategy and R&D Collaboration for Substitution of Rare Earth Resources and Report 2: Development of Mangetocaloric Alloys without Critical Elements

    Lee, Min Ha [Ames Laboratory (AMES), Ames, IA (United States); Ott, Ryan [Ames Laboratory (AMES), Ames, IA (United States)


    A Memorandum of Understanding was signed between the Ames Laboratory and Korea Institute of Industrial Technology (KITECH) in April of 2011 to establish a close cooperative relationship of research on Rare Metals. The Ames Laboratory through its operating contractor, Iowa State University, and the KITECH, as one of the goals of a joint Memorandum of Understanding, made agreement on a Cooperative Research and Development Agreement (CRADA) for a personnel exchange in April of 2012. Ames Laboratory and KITECH would be jointly performing collaboration work in this cooperation as the Parties. The individual backgrounds and capabilities of the Parties are ideally suited to the successful execution of this work. The Ames Laboratory has a history spanning more than 60 years of pioneering work in rare-earth (RE) research. With its team of internationally recognized rare-earth experts, the Ames Laboratory is uniquely positioned to provide the knowledge, expertise and training necessary to help ensure a global leadership position for the United States in rare-earth research, development and applications. The KITECH was founded to promote technological capability of small and medium-sized enterprises in Korea and has a mission of supporting research on materials science and engineering in Korea. In 2009, Korea Institute for Rare Metals (KIRAM) at KITECH was established. KIRAM makes selection and funding decisions for technology projects for strategic rare metals, and provides oversight of R&D programs. The KIRAM is focusing on the commercialization and recycling of particular rare metals. In addition KIRAM will be coordinating government, local universities, and small to medium enterprises to facilitate R&D support for core technologies. KIRAM will be carrying them through to commercialization, and establishing new industry.

  11. Rare-earth oxide nanostructures: rules of rare-earth nitrate thermolysis in octadecylamine.

    Wang, Dingsheng; Wang, Zhongying; Zhao, Peng; Zheng, Wen; Peng, Qing; Liu, Liqin; Chen, Xueyuan; Li, Yadong


    The decomposed regularity of rare-earth nitrates in octadecylamine (ODA) is discussed. The experimental results show that these nitrates can be divided into four types. For rare-earth nitrates with larger RE(3+) ions (RE=rare earth, La, Pr, Nd, Sm, Eu, Gd), the decomposed products exhibited platelike nanostructures. For those with smaller RE(3+) ions (RE=Y, Dy, Ho, Er, Tm, Yb), the decomposed products exhibited beltlike nanostructures. For terbium nitrate with a middle RE(3+) ion, the decomposed product exhibited a rodlike nanostructure. The corresponding rare-earth oxides, with the same morphologies as their precursors, could be obtained when these decomposed products were calcined. For cerium nitrate, which showed the greatest differences, flowerlike cerium oxide could be obtained directly from decomposition of the nitrate without further calcination. This regularity is explained on the basis of the lanthanide contraction. Owing to their differences in electron configuration, ionic radius, and crystal structure, such a nitrate family therefore shows different thermolysis properties. In addition, the potential application of these as-obtained rare-earth oxides as catalysts and luminescent materials was investigated. The advantages of this method for rare-earth oxides includes simplicity, high yield, low cost, and ease of scale-up, which are of great importance for their industrial applications.

  12. Combustion synthesis of bulk nanocrystalline iron alloys

    Licai Fu; Jun Yang; Weimin Liu


    The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on...

  13. Rare Earth Additions in Continuously Cast Steel

    Wilson, William G.; Heaslip, L. J.; Sommerville, I. D.


    Rare earth (lanthanide metals) addiiions to continuously cast steel are particularly advantageous because of their ability to refine as-cast structures, reduce segregation and increase hot ductility at temperatures just below that of solidification. The complete shape control of sulfides in steels containing Rare Earth Metals (REM), whether continuously cast or ingot cast, is primarily responsible for improvements in ductility related mechanical properties, weldability, fatigue resistance and resistance to hydrogen damage. Complete sulfide shape control can be obtained with REM additions at sulfur levels as high as.020%. The greatest improvements, however, are obtained with REM additions to low sulfur steels. However, to achieve full operational advantages afforded by REM, nozzle blockage problems must be circumvented. Water model studies indicate a possible solution.

  14. China's Rare Earth Supply Chain: Illegal Production, and Response to new Cerium Demand

    Nguyen, Ruby Thuy; Imholte, D. Devin


    As the demand for personal electronic devices, wind turbines, and electric vehicles increases, the world becomes more dependent on rare earth elements. Given the volatile, Chinese-concentrated supply chain, global attempts have been made to diversify supply of these materials. However, the overall effect of supply diversification on the entire supply chain, including increasing low-value rare earth demand, is not fully understood. This paper is the first attempt to shed some light on China's supply chain from both demand and supply perspectives, taking into account different Chinese policies such as mining quotas, separation quotas, export quotas, and resource taxes. We constructed a simulation model using Powersim Studio that analyzes production (both legal and illegal), production costs, Chinese and rest-of-world demand, and market dynamics. We also simulated new demand of an automotive aluminum-cerium alloy in the US market starting from 2018. Results showed that market share of the illegal sector has grown since 2007-2015, ranging between 22% and 25% of China's rare earth supply, translating into 59-65% illegal heavy rare earths and 14-16% illegal light rare earths. There will be a shortage in certain light and heavy rare earths given three production quota scenarios and constant demand growth rate from 2015 to 2030. The new simulated Ce demand would require supply beyond that produced in China. Finally, we illustrate revenue streams for different ore compositions in China in 2015.

  15. Influence of Light Rare Earth on Toughness of Welded Seam of LAHS Steel

    李慕勤; 马臣; 刘冬梅


    The influence mechanism of light rare earth elements, which are transited to the welding seam of low-alloy high strength (LAHS) steel through the covering of the electrode, on the toughness of the welding seam was studied. The experimental results show that proper amount of rare earth elements can desulfurate, dehydrogenate, reduce inclusions and purify the structure of the welding seam. Rare earth element additions have the effect on welding seam and, at the same time, the transformation of side-batten ferrite is resisted while the pin-ferrite structure is promoted. The improvement of the toughness of the welding seam is due to the purifying action of rare earth elements as well as their refining effect on the structure. However, the toughness of the welding seam can decrease when the amount of light rare earth elements are added excessively because the crystal grains become coarser, porosities appear and the inclusions increase as well. The experimental results show that the suitable amount of light rare earth element additions is about 2%.

  16. Rare earth optogalvanic spectroscopy: preliminary results

    Destro, Marcelo G.; Neri, Jose W.; Rodrigues, Nicolau A.S.; Silveira, Carlos A.B.; Riva, Rudimar [Instituto de Estudos Avancados (IEAv/EFO), Sao Jose dos Campos, SP (Brazil). Div. de Fotonica]. E-mail:; Victor, Alessandro R. [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil)


    The IEAv has special interest in the studies of rare earth isotope applications in laser medium and integrated optics as well as aerospace research. We are starting to work with Ytterbium, Erbium, Dysprosium and Neodymium laser selective photoionization research. This paper describes the preliminary results of emission and optogalvanic spectroscopy obtained from a Neodymium hollow cathode lamps. Furthermore these results were used to setup our laser systems to work to leads a Nd isotopes selective laser photoionization. (author)

  17. Systematic variation of rare earths in monazite

    Murata, K.J.; Rose, H.J.; Carron, M.K.


    Ten monazites from widely scattered localities have been analyzed for La, Ce, Pr, Nd, Sm, Gd, Y and Th by means of a combined chemical and emission spectrographic method. The analytical results, calculated to atomic percent of total rare earths (thorium excluded), show a considerable variation in the proportions of every element except praseodymium, which is relatively constant. The general variation trends of the elements may be calculated by assuming that the monazites represent different stages in a fractional precipitation process, and by assuming that there is a gradational increase in the precipitability of rare earth elements with decreasing ionic radius. Fractional precipitation brings about an increase in lanthanum and cerium, little change in praseodymium, and a decrease in neodymium, samarium, gadolinium, and yttrium. Deviations from the calculated lines of variation consist of a simultaneous, abnormal increase or decrease in the proportions of cerium, praseodymium, and neodymium with antipathetic decrease or increase in the proportions of the other elements. These deviations are ascribed to abnormally high or low temperatures that affect the precipitability of the central trio of elements (Ce, Pr, Nd) relatively more than that of the other elements. The following semiquantitative rules have been found useful in describing the composition of rare earths from monazite: 1. 1. The sum of lanthanum and neodymium is very nearly a constant at 42 ?? 2 atomic percent. 2. 2. Praseodymium is very nearly constant at 5 ?? 1 atomic percent. 3. 3. The sum of Ce, Sm, Gd, and Y is very nearly a constant at 53 ?? 3 atomic percent. No correlation could be established between the content of Th and that of any of the rare earth elements. ?? 1953.

  18. Phase Behavior of Rare Earth Manganites

    Naoki Kamegashira; Hiromi Nakano; Gang Chen; Jian Meng


    Among complex oxides containing rare earth and manganese BaLn2Mn2O7 (Ln=rare earth) with the layered perovskite type and Ln2(Mn, M)O7 with pyrochlore-related structure were studied since these compounds show many kinds of phases and unique phase transitions. In BaLn2Mn2O7 there appear many phases, depending on the synthetic conditions for each rare earth. The tetragonal phase of so-called Ruddlesden-Popper type is the fundamental structure and many kinds of deformed modification of this structure are obtained. For BaEu2Mn2O7 at least five phases have been identified from the results of X-ray diffraction analysis with the space group P42/mnm, Fmmm, Immm and A2/m in addition to the fundamental tetragonal I4/mmm phase. In the pyrochlore-related type compounds, Ln2Mn2-xMxO7 (M=Ta, Nb, W etc), there also appear several phases with different crystal structures. With regard to every rare earth, Ln2MnTaO7 phase is stable only for excess Ta and can be obtained under high oxygen partial pressure process. This group has trigonal structure with zirkelite type (P3121 space group). On the other hand Ln2Mn2/3Nb4/3O7 phase has monoclinic (C2/c space group) and zirconolite type structure. All of these structural models have the fundamental structure based on HTB (hexagonal tungsten bronze) layers formed by the arrangement of oxygen octahedra.

  19. Anthropogenic Cycles of Rare Earth Elements

    Du, X.; Graedel, T. E.


    This research will develop quantitatively resolved anthropogenic cycles and in-use stocks for the rare earth metals specifically cerium, lanthanum and dysprosium in Japan, China, and the U.S. for the year of 2007. Rare earth elements (REE) is a group of 17 scare metals widely used in a growing number of emerging technologies and have been in high demand for emerging technologies as raw materials during past the three decades. New market participants from newly industrializing countries, primarily China, have had strong impacts on the demand of share. Consequently, the importance to sustain a reliable, steady, uninterrupted supply on global market triggered comprehensive research to recognize and understand the life cycles of rare earths. Moreover, because China plays a dominant role in mining production since 1990, it requires the assessment for the countries, which are almost completely dependent on imports from China with respect to rare earth resources. The study aims to analyze the flows and stocks of rare earth elements individually as elemental form in spite of their natural geological co-occurrence and mixed composition in applications. By applying the method of Material Flow Analysis (MFA) work has been done on evaluating current and historical flows of specific technologically significant materials, for example, copper, zinc, nickel, etc., determining the stocks available in different types of reservoirs (e.g., lithosphere, in-use) and the flows among the reservoirs, developing scenarios of possible futures of metal use, and assessing the environmental and policy implications of the results. Therefore, REE as a new target deserves inclusion because of its potential demand-supply conflict and importance to secure the competitive advantage of technical innovation in future. This work will generate a quantitatively resolved anthropogenic life cycle and in-use stocks for REE for the main target countries for a chosen year, 2007, providing flows and stocks from

  20. Molecular catalysis of rare-earth elements

    Roesky, Peter W. (ed.) [Karlsruhe Institute of Technology (KIT) (Germany). Inst. of Inorganic Chemistry


    This volume reviews the recent developments in the use of molecular rare-earth metal compounds in catalysis. Most of the applications deal with homogenous catalysis but in some cases, heterogeneous systems are also mentioned. The rare-earth elements, which are the lanthanides and their close relatives - scandium and yttrium - have not been in the focus of molecular chemistry for a long time and therefore have also not been considered as homogenous catalysts. Although the first organometallic compounds of the lanthanides, which are tris(cyclopentadienyl) lanthanide complexes, were already prepared in the 1950s, it was only in the late 1970s and early 1980s when a number of research groups began to focus on this class of compounds. One reason for the development was the availability of single crystal X-ray diffraction techniques, which made it possible to characterize these compounds.Moreover, new laboratory techniques to handle highly air and moisture sensitive compounds were developed at the same time. Concomitant with the accessibility of this new class of compounds, the application in homogenous catalysis was investigated. One of the first applications in this field was the use of lanthanide metallocenes for the catalytic polymerization of ethylene in the early 1980s. In the last two or three decades, a huge number of inorganic and organometallic compounds of the rare-earth elements were synthesized and some of them were also used as catalysts. Although early work in homogenous catalysis basically focused only on the hydrogenation and polymerization of olefins, the scope for catalytic application today is much broader. Thus, a large number of catalytic {sigma}-bond metathesis reactions, e.g. hydroamination, have been reported in the recent years. This book contains four chapters in which part of the recent development of the use of molecular rare-earth metal compounds in catalysis is covered. To keep the book within the given page limit, not all aspects could be

  1. Compact Rare Earth Emitter Hollow Cathode

    Watkins, Ronald; Goebel, Dan; Hofer, Richard


    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  2. The iron alloys of the Earth's core

    Caracas, R.; Verstraete, M. J.; Vargas Calderon, A.; Labrosse, S.; Hernlund, J. W.; Gomi, H.; Ohta, K.; Hirose, K.


    We estimate the necessary amount of several light elements - C, S, P, O, Si - as major alloying components to match the observed seismic properties of the Earth's inner core. For this we compute the elastic constants tensors and determine the seismic properties of Fe3X compounds, with X = C, S, P, O and Si, using first-principles calculations. Assuming linear relations and similar temperature corrections of velocities, we obtain as most reasonable silicon and oxygen. We perform the same exercise on Fe-Ni alloys and see a minor effect of Ni on the seismic properties of iron. We compute the electrical conductivity of iron and iron alloys at Earth's core conditions from electron-phonon coupling in the ABINIT implementation. We find an excellent agreement with experimental results for pure hcp iron below 1 mbars. We confidently use our results up to core pressure conditions. We show that the conductivity exhibits saturation at high pressures. We treat in detail the effect of Si on hcp iron and show a marked saturation effect, an increase in anisotropy and a strong dependence with the substitution pattern. The computed values suggest that the outer core should have conductivities in excess of 90 W/K/m, which is considerably larger than current estimates. This implies an inner core younger than 1 bil. years and stratification of the outer core.

  3. Hydrometallurgical method for recycling rare earth metals, cobalt, nickel, iron, and manganese from negative electrodes of spent Ni-MH mobile phone batteries; Metodo hidrometalurgico para reciclagem de metais terras raras, cobalto, niquel, ferro e manganes de eletrodos negativos de baterias exauridas de Ni-MH de telefone celular

    Santos, Vinicius Emmanuel de Oliveira dos; Lelis, Maria de Fatima Fontes; Freitas, Marcos Benedito Jose Geraldo de, E-mail: [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil). Departamento de Quimica; Celante, Vinicius Guilherme [Instituto Federal do Espirito Santo (IFES), Aracruz, ES (Brazil)


    A hydrometallurgical method for the recovery of rare earth metals, cobalt, nickel, iron, and manganese from the negative electrodes of spent Ni-MH mobile phone batteries was developed. The rare earth compounds were obtained by chemical precipitation at pH 1.5, with sodium cerium sulfate (NaCe(SO{sub 4}){sub 2}.H{sub 2}O) and lanthanum sulfate (La{sub 2}(SO{sub 4}){sub 3}.H{sub 2}O) as the major recovered components. Iron was recovered as Fe(OH){sub 3} and FeO. Manganese was obtained as Mn{sub 3}O{sub 4}.The recovered Ni(OH){sub 2} and Co(OH){sub 2} were subsequently used to synthesize LiCoO{sub 2}, LiNiO{sub 2} and CoO, for use as cathodes in ion-Li batteries. The anodes and recycled materials were characterized by analytical techniques. (author)

  4. An Integrated Rare Earth Elements Supply Chain Strategy


    FL: CRC Press, 2005) 1, 61, 59. 7 Gupta and Krishnamurthy, Extractive Metallurgy of Rare Earths, 21, 22, 32; Cindy A. Hurst, ―China‘s Ace in the...Supply Chain, Briefing for Congressional Committees, 27. 17 Ibid, 24. 18 Gupta and Krishnamurthy, Extractive Metallurgy of Rare Earths, 57. 19 Ibid...Oct 12, 2010): 3. 38 Gupta and Krishnamurthy, Extractive Metallurgy of Rare Earths, 94. 39 U.S. Government Accountability Office, Rare Earth

  5. Reduction property of rare earth oxide doped molybdenum oxide


    Rare earth oxide doped molybdenum powders were prepared by the reduction of rare earth nitrites doped MoO3. The effect of rare earth oxide on the reduction behavior of molybdenum oxide had been studied by means of Temperature Programmed Reduction (TPR), thermal analysis, X-ray diffraction. Doping rare earth oxide in the powder could lower the reduction temperature of molybdenum oxide and decrease the particle size of molybdenum. The mechanism for the effects had been discussed in this paper.

  6. Low temperature route for the synthesis of rare earth transition metal borides and their hydrides

    Kramp, S.; Febri, M.; Joubert, J.C. [CNRS UMR 5628, Saint Martin d`Heres (France)


    Synthesis of rare earth-based alloys by the ORD technique consists in the reduction of rare earth oxides in a melt of calcium under argon, and simultaneous diffusion-reaction of the just formed rare earth metal with the other elements. This method has been applied with success to numerous ternary borides containing transition metals such as the magnetic alloys Y{sub 2}Co{sub 14}B, LnCo{sub 4}B, and YCo{sub 3}B{sub 2}. By using a small excess of Ca, boride particles grow in a viscous slurry media containing unreacted (melted) Ca and nanosize CaO particles. Single phase boride alloys can be obtained at 1000{degrees}C as loose micrometer-size particles of very high crystal quality as confirmed by the sharp diffraction peaks on the corresponding X-ray diagrams. Particles can be easily recovered by gentle wishing in diluted weak acid solution, and dried under vacuum at room temperature. This rather low temperature technique is particularly adapted to the synthesis of incongruent melting phases, as well as for the alloys containing volatile rare earth elements (Sm, Yb, Tb,...).

  7. A Low Temperature Route for the Synthesis of Rare Earth Transition Metal Borides and Their Hydrides

    Kramp, S.; Febri, M.; Joubert, J. C.


    Synthesis of rare earth-based alloys by the ORD technique consists in the reduction of rare earth oxides in a melt of calcium under argon, and simultaneous diffusion-reaction of the just formed rare earth metal with the other elements. This method has been applied with success to numerous ternary borides containing transition metals such as the magnetic alloys Y2Co14B, LnCo4B, and YCo3B2. By using a small excess of Ca, boride particles grow in a viscous slurry media containing unreacted (melted) Ca and nanosize CaO particles. Single phase boride alloys can be obtained at 1000°C as loose micrometer-size particles of very high crystal quality as confirmed by the sharp diffraction peaks on the corresponding X-ray diagrams. Particles can be easily recovered by gentle washing in diluted weak acid solution, and dried under vacuum at room temperature. This rather low temperature technique is particularly adapted to the synthesis of incongruent melting phases, as well as for the alloys containing volatile rare earth elements (Sm, Yb, Tb,…).

  8. Combustion synthesis of bulk nanocrystalline iron alloys

    Licai Fu


    Full Text Available The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on the synthesis of nanocrystalline metals and alloys prepared by combustion synthesis technique are reviewed. Then, the mechanical and tribological properties of these materials with microstructure control are discussed.

  9. Combustion synthesis of bulk nanocrystalline iron alloys

    Licai Fu; Jun Yang; Weimin Liu


    The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on the synthesis of nanocrystalline metals and alloys prepared by combustion synthesis technique are reviewed. Then, the mechanical and tribological properties of these materials with microstructure control are discussed.

  10. 2007 China Rare Earths Import & Export Analysis and Suggestions


    @@ Ⅰ. Chinese rare earth import & export status in 2007 China further strengthened regulations on import & export of rare earth products in 2007. Firstly, NDRC changed the guidance for rare earth production from guiding plan into mandatory plan at the year beginning.

  11. China is Planning to Raise rare Earth Resource Tax Again


    <正>In the face of the current situation of the lost WTO dispute on rare earth,and cancellation of export tariff for partial rare earth products,efforts of regulation and integration on rare earth by the state government will again be tightened.Reporters of the Economic Information Daily recently learned from authoritative sources that relevant ministries are

  12. Rare earth elements behavior in Peruibe black mud

    Torrecilha, Jefferson K.; Carvalho, Leandro P.; Gouvea, Paulo F.M.; Silva, Paulo S.C. da, E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    Rare earth elements in sediments have been used as powerful tools for environmental studies because of their behavior during geochemical processes and are also widely accepted as reliable provenance tracers because they are largely water-immobile and thus behave conservatively during sedimentary processes. The Peruibe Black Mud (PBM) is a sedimentary deposit originated from the interactions of marine sediments and organic matter in an estuarine environment that originates a peloid currently used for medicinal purposes. The objective of this study was to examine rare earth elements pattern distribution in the Peruibe black mud sedimentary deposit as a proxy for its geochemical development. Elemental ratios such as LaN/YbN, Th/U and La/Th were determined and a normalization of the mean rare earth elements concentrations in the samples related to NASC indicates that the light (La to Eu) rare earth elements present values close to the unity while the heavy (Tb to Lu) rare earth elements are depleted related to NASC. It can be observed that the light rare earth elements present enrichment values slightly enriched over the unity while the heavy rare earth elements present values generally below the unity reflecting the enrichment of the light rare earth elements over the heavy rare earth. Rare earth elements concentrations determined in Peruibe black mud samples showed a distribution similar to that found in the NASC for the light rare earth elements and depleted for the heavy rare earth elements. (author)

  13. 微量RE对SnAgCu无铅钎料力学性能和润湿性能的影响%Effect of Rare Earth Elements on Mechanical Property and Wettability of SnAgCu Solder Alloy

    杨洁; 冯晓乐; 程光辉


    利用光学显微镜、扫描电镜和能谱分析仪等检测手段,研究了微量RE对低银Sn2.5Ag0.7Cu无铅钎料的力学性能和润湿性能影响.结果表明,添加微量RE可以提高该钎料的力学性能,改善润湿性能.当RE添加量为0.1wt%时,钎料的伸长率和拉伸强度最大,此时,该钎料在Cu焊盘上的铺展面积也最大.但过量的RE会导致性能的下降.这些性能的改变与微量RE对其显微组织的影响有关.%The effect of rare earth elements on the mechanical properties and wettability of Sn2.5AgO.7Cu solder were investigated by optical microscopy, SEM and EDS. The results indicate that the addition of trace RE can improve the properties of SnAgCu lead-free solder. The elongation and tensile strength and spreading area on Cu can reach the optimal values, when RE addition is 0. Lwt%. But excessive RE can lead to the decline of performance. The property changes of Sn2.5Ag0.7Cu solder are attributed to the change of the microstructure caused by trace rare earths additions.

  14. Enhanced separation of rare earth elements

    Lyon, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Herbst, R. S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Soderstrom, M. D. [Cytec Solvay Group, Tempe, AZ (United States); Jakovljevic, B. [Cytec Solvay Group, Niagara Falls, ON (Canada)


    Industrial rare earth separation processes utilize PC88A, a phosphonic acid ligand, for solvent extraction separations. The separation factors of the individual rare earths, the equipment requirements, and chemical usage for these flowsheets are well characterized. Alternative ligands such as Cyanex® 572 and the associated flowsheets are being investigated at the pilot scale level to determine if significant improvements to the current separation processes can be realized. These improvements are identified as higher separation factors, reduced stage requirements, or reduced chemical consumption. Any of these improvements can significantly affect the costs associated with these challenging separation proccesses. A mid/heavy rare earth element (REE) separations flowsheet was developed and tested for each ligand in a 30 stage mixer-settler circuit to compare the separation performance of PC88A and Cyanex® 572. The ligand-metal complex strength of Cyanex® 572 provides efficient extraction of REE while significantly reducing the strip acid requirements. Reductions in chemical consumption have a significant impact on process economics for REE separations. Partitioning results summarized Table 1 indicate that Cyanex® 572 offers the same separation performance as PC88A while reducing acid consumption by 30% in the strip section for the mid/heavy REE separation. Flowsheet Effluent Compositions PC88A Cyanex® 572 Raffinate Mid REE Heavy REE 99.40% 0.60% 99.40% 0.60% Rich Mid REE Heavy REE 2.20% 97.80% 0.80% 99.20% Liquor Strip Acid Required 3.4 M 2.3 M Table 1 – Flowsheet results comparing separation performance of PC88A and Cyanex® 572 for a mid/heavy REE separation.

  15. Rare-Earth-Free Traction Motor: Rare Earth-Free Traction Motor for Electric Vehicle Applications



    REACT Project: Baldor will develop a new type of traction motor with the potential to efficiently power future generations of EVs. Unlike today’s large, bulky EV motors which use expensive, imported rare-earth-based magnets, Baldor’s motor could be light, compact, contain no rare earth materials, and have the potential to deliver more torque at a substantially lower cost. Key innovations in this project include the use of a unique motor design, incorporation of an improved cooling system, and the development of advanced materials manufacturing techniques. These innovations could significantly reduce the cost of an electric motor.

  16. Note: Portable rare-earth element analyzer using pyroelectric crystal

    Imashuku, Susumu, E-mail:; Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)


    We report a portable rare-earth element analyzer with a palm-top size chamber including the electron source of a pyroelectric crystal and the sample stage utilizing cathodoluminescence (CL) phenomenon. The portable rare-earth element analyzer utilizing CL phenomenon is the smallest reported so far. The portable rare-earth element analyzer detected the rare-earth elements Dy, Tb, Er, and Sm of ppm order in zircon, which were not detected by scanning electron microscopy-energy dispersive X-ray spectroscopy analysis. We also performed an elemental mapping of rare-earth elements by capturing a CL image using CCD camera.

  17. Thermoelectric transport in rare-earth compounds

    Koehler, Ulrike


    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce{sub 3}Rh{sub 4}Sn{sub 13} are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu{sub 1-x}Yb{sub x}Rh{sub 2}Si{sub 2} and Ce{sub x}La{sub 1-x}Ni{sub 2}Ge{sub 2} by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  18. Jiangxi’s Proved Reserve of Copper, Tungsten and Rare Earth Topped 4 Million Tonnes


    <正>The reporter learned from Jiangxi Provincial Geological and Mineral Resource Bureau that Jiangxi’s geological prospecting has made significant progress, copper, tungsten, rare earth, silver, and iron ore varieties have fulfilled Stage 1 target, at present the verified and

  19. Research on toughening mechanisms of alumina matrix ceramic composite materials improved by rare earth additive

    ZHANG Xihua; LIU Changxia; LI Musen; ZHANG Jianhua


    Mixed rare earth elements were incorporated into alumina ceramic materials. Hot-pressing was used to fabricate alumina matrix composites in nitrogen atmosphere protection. Microstructures and mechanical properties of the composites were tested. It was indicated that the bending strength and fracture toughness of alumina matrix ceramic composites sintered at 1550℃ and 28 Mpa for 30 min were improved evidently. Besides mixed rare earth elements acting as a toughening phase, AlTiC master alloys were also added in as sintering assistants, which could prompt the formation of transient liquid phase, and thus nitrides of rare earth elements were produced. All of the above were beneficial for improving the mechanical properties of alumina matrix ceramic composites.

  20. 6061铝合金表面无铬稀土镧转化膜性能的研究%Research on Performance of Chrome-free Rare Earth Lanthanum Conversion Coating on 6061 Aluminum Alloy Surface

    李红玲; 刘清玲


    [摘 要] 利用极化曲线方法,研究了以La(NO3)3·6H2O为促进剂的磷酸盐转化膜的耐蚀性,同时与铬磷化膜及无稀土促进的单纯磷酸盐膜的耐蚀性进行了对比;通过划格法和全浸腐蚀试验,研究了这三种转化膜与有机涂层间的结合力.结果发现:与单纯磷酸盐膜相比,稀土促进生成的磷酸盐膜中的传输阻力增加,耐蚀性明显增强,而与铬磷化膜相比,二者在弱极化区的耐蚀性能相近;稀土促进生成的磷酸盐膜与有涂层间的结合力明显优于铬磷化膜.%The anti-corrosion of the conversion coating which is formed by La(NO3) 3 · 6H2O was evaluated with polarization curve,and also compared the chromium phosphate film and non-rare phosphate conversion coating.Adhesion force between the conversion coatings and the organic coating were studied through crossing grid method and immersing corrosion test.The results showed that the transmission resistance of conversion coating with rare earth additive was increased by comparing with non-rare phosphate conversion coating; The anti-corrosion of the conversion coating was increased noticeably.But comparing with chromium phosphting,in the weak polarized scope,both of the corrosion resistances were close.Adhesion force between the conversion coating with rare earth as additive and the organic coating was obviously superior to that of chromate phosphate process.

  1. Recovery of Rare Earths, Niobium, and Thorium from the Tailings of Giant Bayan Obo Ore in China

    Yu, Xiu-Lan; Bai, Li; Wang, Qing-Chun; Liu, Jia; Chi, Ming-Yu; Wang, Zhi-Chang


    The recovery of rare earths, niobium, and thorium from Bayan Obo's tailings has been investigated because the Bayan Obo ore is rich in rare earths and rich in niobium and thorium, but it is mined mainly as an iron ore and will be used up soon. By carbochlorination between 823 K (550 °C) and 873 K (600 °C) for 2 hours, 76 to 93 pct of rare earths were recovered from the tailings, which were much higher than those from Bayan Obo's rare earth concentrate, together with 65 to 78 pct of niobium, 72 to 92 pct of thorium, 84 to 91 pct of iron, and 81 to 94 pct of fluorine. This suggests a cooperative reaction mechanism that carbochlorination of iron minerals (and carbonates) in the tailings enhances that of rare earth minerals, which is supported by a thermodynamic analysis. Subsequently, niobium separation from the low-volatile, ultrahigh iron chloride mixture was achieved efficiently by selective oxidation with Fe2O3. This process, combined with the best available technologies for separation of rare earths and thorium from the involatile chloride mixture and for comprehensively using other valuable elements, allows the ore to minimize radioactive waste and to use rare metal resources sustainably in the future.

  2. Study on Magnetic Responsibility of Rare Earth Ferrite/Polyacrylamide Magnetic Microsphere

    Zhang Ming; Wang Zhifeng; Zhang Hong; Dai Shaojun; Qiu Guanming; Okamoto Hiroshi


    In inverse microemulsion, rare earth ferrite/polyacrylamide magnetic microsphere were prepared and their magnetic responsibility were studied by magnetic balance. Results indicate that the magnetic responsibility of microsphere relates to magnetic moment of rare earth ion, and it can be improved by the addition of dysprosium ion of high magnetic moment. Dysprosium content has an effect on magnetic responsibility of dysprosium ferrite/polyacrylamide magnetic microsphere. The microsphere displays strong magnetic responsibility when the molar ratio of Dy3+/iron is 0.20.

  3. Influence of rare earths addition on residual stress of Fe-based coating prepared by brush plating technology

    JIN Guo; LU Bingwen; HOU Dingding; CUI Xiufang; SONG Jiahui; LIU Erbao


    The effect of rare earths (La, Ce and Pr) addition on residual stress in iron coatings prepared by brush plating was investi-gated. The results showed that the addition of rare earth transformed the residual stress in the coating from tensile to compressive. To relieve the residual stress, on the one hand, RE elements segregated at the grain boundaries which restricted the coalescence of the grains and provided more capability of grain deformation. On the other hand, RE elements could purify detrimental element and ab-sorb hydrogen atoms in the coating. Among the three rare earths, elements lanthanum showed the most significant effect on surface morphology and residual stress.

  4. 稀土Gd-铁粉煤灰预处理甲基橙模拟染料废水的研究%Study on rare earth Gd-iron and fly ash used for pretreating simulated methyl orange dyeing wastewater

    杨花; 王静; 刘凤娴; 史美鲜


    Stimulated methyl orange wastewater has been treated by micro-electrolysis as the main process,and scrap iron and fly ash as micro-electrolysis packings,so as to obtain a new route for the utilization of fly ash,and to discuss the new methods for improving the treatment effectiveness of micro-electrolysis by using rare earth Gd catalysis. The results show that fly ash can replace activated carbon in micro-electrolysis reaction and has good treatment effectiveness. Rare earth Gd can significantly speed up the reaction rate and improve the decolorization rate and degradation rate of methyl orange. The optimal operation parameters are as follows:influent pH is 3.5, reaction time 60 min,rare earth Gd added in form of Gd3+solution(3.08 g/L) with a dosage of 10 mL,scrap iron and fly ash dosage 150 g/L,and m(fly ash)∶m(scrap iron)=2∶1.%以甲基橙模拟染料废水为处理对象,微电解法为主体工艺,采用铁屑和粉煤灰作为微电解填料,以获得粉煤灰资源化利用的新途径,并探讨稀土Gd催化提高微电解处理效果的新方法。结果表明,粉煤灰可以替代活性炭参与微电解反应,并有良好的处理效果,稀土Gd能明显加快反应速率并提高甲基橙的脱色率和降解率。试验最佳运行参数:进水pH为3.5,反应时间60 min,稀土Gd以Gd3+溶液(3.08 g/L)形式投加,投加量为10 mL,铁粉煤灰投加量为150 g/L,m(粉煤灰)∶m(铁屑)为2∶1。

  5. Effect of Rare Earth Element Ce on Microstructure and Properties of Aluminum Rod for Electrical Purpose

    Li Pengfei; Wang Yunli; Gao Xizhu; Wang Zaiyun


    The effect of rare earth element Ce on microstructure, electrical conductivity and mechanical properties was studied.Using optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffractometer, the microstructure and phase composition of aluminum rod for electrical purpose were measured and analyzed.The results indicate that rare earth element Ce can considerably refine grain size of aluminum rod for electrical purpose,improve the regular distribution pattern of the impurity, such as silicon and iron which present in the aluminum matrix,form stable metal compound with pernicious impurity.This metal compound precipitates on the crystal boundary.As a result, the solid solubility of impurity in aluminum reduce, and the electrical conductivity of aluminum rod for electrical purpose is improved.It is found that the mechanical properties of aluminum rod for electrical purpose are improved by rare earth element in certain range of RE addition.

  6. Hydrophobicity of rare-earth oxide ceramics

    Azimi, Gisele; Dhiman, Rajeev; Kwon, Hyuk-Min; Paxson, Adam T.; Varanasi, Kripa K.


    Hydrophobic materials that are robust to harsh environments are needed in a broad range of applications. Although durable materials such as metals and ceramics, which are generally hydrophilic, can be rendered hydrophobic by polymeric modifiers, these deteriorate in harsh environments. Here we show that a class of ceramics comprising the entire lanthanide oxide series, ranging from ceria to lutecia, is intrinsically hydrophobic. We attribute their hydrophobicity to their unique electronic structure, which inhibits hydrogen bonding with interfacial water molecules. We also show with surface-energy measurements that polar interactions are minimized at these surfaces and with Fourier transform infrared/grazing-angle attenuated total reflection that interfacial water molecules are oriented in the hydrophobic hydration structure. Moreover, we demonstrate that these ceramic materials promote dropwise condensation, repel impinging water droplets, and sustain hydrophobicity even after exposure to harsh environments. Rare-earth oxide ceramics should find widespread applicability as robust hydrophobic surfaces.

  7. Gyroscopic g factor of rare earth metals

    Ogata, Y.; Chudo, H.; Ono, M.; Harii, K.; Matsuo, M.; Maekawa, S.; Saitoh, E.


    We develop the in situ magnetization measurement apparatus for observing the Barnett effect consisting of a fluxgate sensor, a high speed rotor with frequencies of up to 1.5 kHz, and a magnetic shield at room temperature. The effective magnetic field (Barnett field) in a sample arising from rotation magnetizes the sample and is proportional to the rotational frequency. The gyroscopic g factor, g ' , of rare earth metals, in particular, Gd, Tb, and Dy, was estimated to be 2.00 ± 0.08, 1.53 ± 0.17, and 1.15 ± 0.32, respectively, from the slopes of the rotation dependence of the Barnett field. This study provides a technique to determine the g ' factor even in samples where the spectroscopic method may not be available.

  8. Parity Violation Experiments with Rare Earth Atoms

    Budker, Dmitry


    Since the first suggestions (V. A. Dzuba, V. V. Flambaum, and I. B. Khriplovich, Z. Phys. D1, 243 (1986).), (A. Gongora and P. G. H. Sandars, J. Phys. B 19, L291 (1986).) to search for parity violation in the rare earth atoms, experiments have been carried out by groups in Novosibirsk, Oxford, Hiroshima and Berkeley with Sm, Yb and Dy. The status of these experiments will be reviewed, with some details given on recent Berkeley Dy results ( A.-T. Nguyen, D. Budker, D. DeMille, and M. Zolotorev, Submitted to Phys. Rev. A.). Progress of the Berkeley Yb experiment ( D. DeMille, Phys. Rev. Lett. 74, 4165 (1995).), ( C.J. Bowers, D. Budker, E.D. Commins, D. DeMille, S.J. Freedman, A.-T. Nguyen, S.-Q. Shang, and M. Zolotorev, Phys. Rev. A 53, 3103-9(1996). ) will be described elsewhere at this meeting by C. J. Bowers et al.

  9. Magnetic anisotropies of rare-earth compounds

    Loewenhaupt, M.; Rotter, M.; Kramp, S.


    There are two kinds of magnetic anisotropy in rare-earth compounds: the single-ion anisotropy caused by the crystal field (CF) and the anisotropy of the two-ion interactions. Both types of anisotropy have to be considered to arrive at a consistent description of the magnetic properties of the orthorhombic intermetallic compound NdCu 2. From the analysis of NdCu 2 we can derive predictions for the type of ordering in other isostructural RCu 2 compounds, that agree well with experimental results: If the magnetic moments point into the crystallographic b-direction, an ordering wave vector of (2/3 0 0) is expected. If the moments are oriented perpendicular to b then the ordering wave vector is (2/3 1 0) .

  10. Effect on Rare-Earth Element Lanthanum for Bond Strength of Electrodeposited Nickel

    Song Bo; Zhang Xinyu; Jin Lihong; Zhu Yuansong; Mu Tao; Sui Zhitong


    The bond strength of electrodeposited nickel from common electroplate liquid and rare-earth electroplate liquid was tested and contrasted. Electrodeposited nickel of high bond strength was obtained by method of electro-plate nickel with one step and special pretreatment on the surface of aluminum-alloy substrate. The bond strength between the aluminum-alloy substrate and the electrodeposited nickel was tested by the method of heat shock. Then the effect on the bond strength of the electrodeposited nickel from rare-earth compound, the thickness of the electrodeposited nickel,temperature and current density were analyzed. The experimental result shows that the bond strength between the aluminum-alloy substrate and the electrodeposited nickel is 26 MPa under the following condition( current density: 0.2 ~ 0.6 A · dm-2, thickness of the nickel electrodeposition: 8 ~ 15 μm, and temperature of the electroplate liquid: 8 ~ 25 ℃ ).

  11. Opinions on hot discussions in connection with rare earths recently

    SONG Hongfang; HONG Mei


    @@ Rare earth industry, with production value less than 30 trillion yuan, has become the hot topic both inside China and in the rest of the world since 2009. Even in stock market, rare earth was one of the most active sectors. Media in various countries, specialists in different fields and many political figures worldwide as well as some netizens showed extraordinary concerns on rare earths. Many heated arguments were made on the hot and even some sensitive topics about rare earth industry. Rare earth issues seem to be beyond the industrial production today, but the subject focused on economy, politics and strategic importance. The word "rare earth" was a yearly hot point or a key word in 2010.

  12. Study on Mechanism of Rare Earth PVC Stabilizer

    彭振博; 胡斌; 苏庆德; 曲锦忠


    Rare earth compounds can be used as PVC thermal stabilizers. According to the infrared spectra of the mixture of PVC and some stearates, the mechanism of stabilization of different stearates was studied. The specialty of rare earth stabilizers was found. They can change the conformation of PVC and restrain the elimination of HCl. From this aspect, the unique synergetic effect with other stabilizers of rare earth compounds can be explained.

  13. Analysis and Outlook of Global Rare Earth Market

    XIONG Jiaqi


    @@ When enterd into 21st century,global rare earth market exhibits pleasing situation in recent years,profitig from fast development of global economy.China represented nearly 60% of global rare earth consumption in 2007.Rare earth consumtion in five advanced materisls including permanent magnets,polishing powder,hydrogen storage materisls,fluorescent materials and auto catalysts accounted for 60% of the tutal consumption.

  14. GRNM Likely to Spearhead Reshuffle of Guangdong Rare Earth Industry


    <正>"Guangdong intends to build a rare earth platform named Guangdong Rare Earth Group, and the plan has been probably approved recently." An insider of local government said, "although there is no final conclusion, but the Guangdong’s intention to build a general platform of rare earth is clear." Since Guangdong Rising Nonferrous Metals Group Co., Ltd. (GRNM) is the only local state-owned enterprise leading

  15. China Limits the Mining Quantity of Tungsten and Rare Earth


    <正>Based on a notice issued by the Ministry of Land Resources, China’s tungsten mining quantity in 2006 will be controlled to 59,060 tons in concentrates form, which include 4,250 tons of recycled tungsten. And the rare earth mining quantity in 2006 will also be controlled to 86,620 tons (REO) including 8,320 tons of heavy rare earth and 78,200 tons of light rare earth.

  16. Formation cause,composition analysis and comprehensive utilization of rare earth solid wastes

    许涛; 彭会清


    Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were ...

  17. Enhanced Magnetic Moment of the Iron in a Metastable Iron-Mercury Alloy

    Pedersen, Michael Stanley; Mørup, Steen; Linderoth, S.;


    Ultrafine magnetic particles consisting of a metastable iron-mercury alloy have been investigated in the range 15 K to 200 K by Mossbauer spectroscopy and magnetization measurements. The effective magnetic moment of iron in the iron mercury alloy is found to be enhanced above the value for alpha-...

  18. Hydrogenation of the rare earth alloys for production negative electrodes of nickel-metal hydride batteries; Hidrogenacao de ligas a base de terras raras para fabricacao de eletrodos negativos de baterias de niquel-hidreto metalico

    Casini, Julio Cesar Serafim


    In this work were studied of La{sub 0.7-x}Mg{sub x} Pr{sub 0.3}Al{sub 0.3}Mn{sub 0.4}Co{sub 0.5}Ni{sub 3.8} (X = 0 and 0.7) alloys for negative electrodes of the nickel-metal hydride batteries. The hydrogenation of the alloys was performed varying pressing of H{sub 2} (2 and 10 bar) and temperature (room and 500 Degree-Celsius ). The discharge capacity of the nic kel-metal hydride batteries were analyzed in ARBIN BT- 4 electrical test equipment. The as-cast alloys were analyzed by scanning electron microscopy (SEM), energy disperse spectroscopy (EDX) and X-Ray diffraction. The increasing Mg addition in the alloy increases maximum discharge capacity but decrease cycle life of the batteries. The maximum discharge capacity was obtained with the Mg{sub 0.7}Pr{sub 0.3}Al{sub 0.3}Mn{sub 0.4}Co{sub 0.5}Ni{sub 3.8} alloy (60 mAh) and the battery which presented the best performance was La{sub 0.4}Mg{sub 0.3}Pr{sub 0.3}Al{sub 0.3}Mn{sub 0.4}Co{sub 0.5}Ni{sub 3.8} alloy (53 mAh and 150 cycles). The H{sub 2} capability of absorption was diminished for increased Mg addition and no such effect occurs for Mg{sub 0.7}Pr{sub 0.3}Al{sub 0.3}Mn{sub 0.4}Co{sub 0.5}Ni{sub 3.8} alloy. (author)

  19. Study on Copolymerization of Rare Earth-Carboxylic Acid Complex

    Qiu Guanmin(邱关明); Zhang Ming(张明); Yan Chang hao(严长浩); Zhou Lanxiang(周兰香); Dai Shaojun(戴少俊); Okamo to Hiroshi


    Complex of rare earth with carboxylic acid was prepared by precipita tion and direct method. It was copolymerized with such monomers as acrylic acid and other ones to synthesize ionomer of rare earth and organic polymer with different rare earth contents. Its glass-transition temperature and heat stability were analyzed by TG and DTA. Infra-red detector was used to show its structure. The effect of rare earth complex prepared by different methods on copolymerization and properties of copolymers was also discussed.

  20. Storing Solar Energy Performance on Rare Earth Windowpane

    Li Baojun; Zhou Yao; Fu Li; Yang Tao; Li Tiansi; Li Ying


    The windowpane as the enclosure and decorative component of buildings is main part of energy consumption and the heat loss through window is almost 4% of the heating consumption in buildings. Using rare earth element,the glass can possess the performance of absorbing sunlight, storing heat, increasing the temperate of itself, and decreasing the inner heat load so as to play the double functions of saving energy and environmental protection. The experiment method of the rare earth windowpane, and analyses sunlight absorbing process of the rare earth element on photoelectric principle, and gives the changing curve with environment temperate -time of the rare earth windowpane surface were introduced.

  1. The Rare Earth Magnet Industry and Rare Earth Price in China

    Ding Kaihong


    Full Text Available In the past four years, the price of rare earth metal fluctuates sharply for many reasons. Currently, it has become more stable and more reasonable. This presentation is focused on the effect about the rare earth metal price. Some motor manufacturers have shifted from rare earth permanent magnet to ferrite magnet. Many motor manufacturers changed the design for the motor cooling system to make the motor function at a lower temperature. Thus the consumption of Dy can be markedly reduced. As for manufacturer of NdFeB magnet, we are also trying to optimize our process to reduce to dependence of HREE such as Dy and Tb. HS process have been introduced to solve the problem. With more and more people focusing and engaging on the REE industry, the price of REE will be more transparent without too many fluctuations. China is considering the problems of balancing the environment, energy sources, and labor sources. The application field about NdFeB such as wind turbine generator, HEV/EV, FA /OA is flourishing.

  2. Influence of rare earth vermicularizing alloy for vermicular graphite east iron pieces%稀土蠕化剂对蠕墨铸铁生产的影响

    蒋勇强; 刘春雷



  3. Improved Rare-Earth Emitter Hollow Cathode

    Goebel, Dan M.


    An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out

  4. Rare earth-ruthenium-magnesium intermetallics

    Stein, Sebastian; Kersting, Marcel; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie


    Eight new intermetallic rare earth-ruthenium-magnesium compounds have been synthesized from the elements in sealed niobium ampoules using different annealing sequences in muffle furnaces. The compounds have been characterized by powder and single crystal X-ray diffraction. Sm{sub 9.2}Ru{sub 6}Mg{sub 17.8} (a=939.6(2), c=1779(1) pm), Gd{sub 11}Ru{sub 6}Mg{sub 16} (a=951.9(2), c=1756.8(8) pm), and Tb{sub 10.5}Ru{sub 6}Mg{sub 16.5} (a=942.5(1), c=1758.3(4) pm) crystallize with the tetragonal Nd{sub 9.34}Ru{sub 6}Mg{sub 17.66} type structure, space group I4/mmm. This structure exhibits a complex condensation pattern of square-prisms and square-antiprisms around the magnesium and ruthenium atoms, respectively. Y{sub 2}RuMg{sub 2} (a=344.0(1), c=2019(1) pm) and Tb{sub 2}RuMg{sub 2} (a=341.43(6), c=2054.2(7) pm) adopt the Er{sub 2}RuMg{sub 2} structure and Tm{sub 3}Ru{sub 2}Mg (a=337.72(9), c=1129.8(4) pm) is isotypic with Sc{sub 3}Ru{sub 2}Mg. Tm{sub 3}Ru{sub 2}Mg{sub 2} (a=337.35(9), c=2671(1) pm) and Lu{sub 3}Ru{sub 2}Mg{sub 2} (a=335.83(5), c=2652.2(5) pm) are the first ternary ordered variants of the Ti{sub 3}Cu{sub 4} type, space group I4/mmm. These five compounds belong to a large family of intermetallics which are completely ordered superstructures of the bcc subcell. The group-subgroup scheme for Lu{sub 3}Ru{sub 2}Mg{sub 2} is presented. The common structural motif of all three structure types are ruthenium-centered rare earth cubes reminicent of the CsCl type. Magnetic susceptibility measurements of Y{sub 2}RuMg{sub 2} and Lu{sub 3}Ru{sub 2}Mg{sub 2} samples revealed Pauli paramagnetism of the conduction electrons.

  5. 铝合金表面无铬磷酸盐稀土转化膜的成膜机理及耐蚀性研究%Study on the Film Forming Mechanism and Corrosion Resistance of Non-chromium Phosphate Rare Earth Conversion Coating on Al Alloy

    李红玲; 付小宁


    从磷化成膜过程的电化学行为和稀土对磷化膜生长过程的影响两方面,对6061铝合金表面一种不合铬的复合磷酸盐膜的成膜机理进行了研究,并利用极化曲线对其耐蚀性进行了初步探究.结果表明:磷化成膜过程主要分为4个阶段,即基体侵蚀期、晶体初步形成期、基体再溶解和晶体形成期、基体溶解和晶体生长达到平衡期;稀土化合物的引入,提高了磷化膜的耐蚀性,缩短了磷化时间,同时也促进了反应离子在金属表面的吸附,形成多个活性点,有利于新的结晶均匀增长,极大改善了磷化膜的表面质量.%The electrochemical behavior of film process and the effect of rare earth on a phosphating film's growth process were studied. The phosphating film was formed on 6061 aluminium alloy surface, it was non-chromium phosphate rare earth conv ersion coating. At the same time it's corrosion resistance was explored preliminarily by making use of the polarization curve. The results show that this bonderizing process has mainly four stages: this bonderizing process has mainly the basement corroding scheduled time, crystal first formation scheduled time, basement dissolve again and crystal formation scheduled time, basement dissolve and crystal growth equilibration scheduled time. With the help of rare earth, the corrosion-resistance of the bonderizing film is raised, and phosphating time is shortened, at the same time the reaction ion being in metal outside adsorption is boosted and many active point was formed. This is beneficial to the new crystal's incresament homogeneously. Therefore the bonderizing film surface mass is improved greatly.

  6. Ultrasonic attenuation in rare-earth monoarsenides



    The present paper deals with the theoretical calculation of mechanical and thermophysical properties of rare-earth monoarsenides, XAs (X: Np, Pu, Th and U) using elastic constants as the input parameters. These second- and third-order elastic constants (SOECs and TOECs) are determinedin the temperature range 100–500K using Coulomb and Born–Mayer potential upto second nearest neighbours. In order to provide the link between mechanical and dynamical behaviour of crystals, parameters such as Young’s modulus, bulk modulus, Poisson’s ratio etc. are also calculated.In addition, the Cauchy relationship is obeyed by the chosen monoarsenides and are fairly anisotropic, which results in the measurement of longitudinal and shear wave velocities along $\\langle100 \\rangle$, $\\langle110\\rangle$ and $\\langle 111\\rangle$ directions. The toughness/fracture $(G/BT)$ ratio is greater than 0.60, which implies that XAs compounds are brittle at room temperature. Further, the Debye temperature is computed using Debye average velocity as the input parameter. It helps in the characterization of lattice vibrations of a solid. In this work, ultrasonic attenuation due to phonon–phonon interaction$\\alpha/f^2_{\\rm p−p}$ and thermoelastic loss $\\alpha/f ^{2}$th are computed for XAs from 100 to 500K using Mason’s theory. It further helps in evaluating the microstructural properties of the chosen materials. The obtained results indicate that XAs is mechanically stable and are compared with data availablein the literature.

  7. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India

    E S Challaraj Emmanuel; T Ananthi; B Anandkumar; S Maruthamuthu


    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  8. Research trends in rare earths: A preliminary analysis



    The research trend in rare earths has been studied using the Chemical Abstracts (CA) data.The number of papers published from China has been increasing very rapidly since 2001 and today China is the top country in terms of paper contribution on rare earths.This article presents a comparative study of R & D trends among China,Japan and USA.

  9. Shanghai Rare Earth Industry Scale is Expected to Double


    <正>A new organization in the rare earth industry circle in Shanghai initiated and set up by 14 enterprises and public institutions called "Shanghai Rare Earth Association", formally declared its establishment recently. This marked China’s only specialized and non-profit

  10. Imports εt Exports Review of Chinese Rare Earths


    @@ China developed herself from being predominant at RE resources into a country with the largest production, the highest export volume and the largest application of rare earth products in the world. Today, China plays a leading role in the global rare earth market.

  11. Review and outlook of 2008 China rare earth market

    ZHANG Lihua


    @@ I.Environment and trend of RE market 1.Operation environment in 2008 Chinese government further strengthened its macro-control on rare earth industry in 2008.Mandatory planning policy was implemented in the production of rare earth minerals and smelted products.

  12. Rare earth silicide nanowires on silicon surfaces

    Wanke, Martina


    The growth, structure and electronic properties of rare earth silicide nanowires are investigated on planar and vicinal Si(001) und Si(111) surfaces with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy (ARPES). On all surfaces investigated within this work hexagonal disilicides are grown epitaxially with a lattice mismatch of -2.55% up to +0.83% along the hexagonal a-axis. Along the hexagonal c-axis the lattice mismatch is essentially larger with 6.5%. On the Si(001)2 x 1 surface two types of nanowires are grown epitaxially. The socalled broad wires show a one-dimensional metallic valence band structure with states crossing the Fermi level. Along the nanowires two strongly dispersing states at the anti J point and a strongly dispersing state at the anti {gamma} point can be observed. Along the thin nanowires dispersing states could not be observed. Merely in the direction perpendicular to the wires an intensity variation could be observed, which corresponds to the observed spacial structure of the thin nanowires. The electronic properties of the broad erbium silicide nanowires are very similar to the broad dysprosium silicide nanowires. The electronic properties of the DySi{sub 2}-monolayer and the Dy{sub 3}Si{sub 5}-multilayer on the Si(111) surface are investigated in comparison to the known ErSi{sub 2}/Si(111) and Er{sub 3}Si{sub 5}/Si(111) system. The positions and the energetic locations of the observed band in the surface Brillouin zone will be confirmed for dysprosium. The shape of the electron pockets in the (vector)k {sub parallel} space is elliptical at the anti M points, while the hole pocket at the anti {gamma} point is showing a hexagonal symmetry. On the Si(557) surface the structural and electronic properties depend strongly on the different preparation conditions likewise, in particular on the rare earth coverage. At submonolayer coverage the thin nanowires grow in wide areas

  13. Some Rare Earth Metallic Organohydrides with Biindenyl as the Ligand


    @@ Introduction It is well known that organometallic hydrides of rare earth metals are the catalysts and reducing reagents for the catalysis polymerization of alkenes and the catalysis hydrogenation of alkenoalkynes. There are four methods for the syntheses of organometallic hydrides of rare earth metals: (1) the thermal atomization of metals, I. E. , the interaction of a rare earth metal with alkenes with a terminal alkyne; (2) the Ln-C σ bond is broken with H2; (3) metallic hydride replacement[1], I. E., NaBH4, LiA1H4 and Na can be used to react with organometallic compounds of rare earth metals; (4) the elimination ofβ-H, I. E. , in the presence of LiC1, the elimination of theβ-H of the alkyl compounds of rare earth metals gives the target product. The organohydrides of biindenyl samarium, biindenyl gadolinium and biin denyl dysprosium were obtained with NaH reduction method.

  14. Combinatorial investigation of rare-earth free permanent magnets

    Fackler, Sean Wu

    The combinatorial high throughput method allows one to rapidly study a large number of samples with systematically changing parameters. We apply this method to study Fe-Co-V alloys as alternatives to rare-earth permanent magnets. Rare-earth permanent magnets derive their unmatched magnetic properties from the hybridization of Fe and Co with the f-orbitals of rare-earth elements, which have strong spin-orbit coupling. It is predicted that Fe and Co may also have strong hybridization with 4d and 5d refractory transition metals with strong spin-orbit coupling. Refractory transition metals like V also have the desirable property of high temperature stability, which is important for permanent magnet applications in traction motors. In this work, we focus on the role of crystal structure, composition, and secondary phases in the origin of competitive permanent magnetic properties of a particular Fe-Co-V alloy. Fe38Co52V10, compositions are known as Vicalloys. Fe-CoV composition spreads were sputtered onto three-inch silicon wafers and patterned into discrete sample pads forming a combinatorial library. We employed highthroughput screening methods using synchrotron X-rays, wavelength dispersive spectroscopy, and magneto-optical Kerr effect (MOKE) to rapidly screen crystal structure, composition, and magnetic properties, respectively. We found that in-plane magnetic coercive fields of our Vicalloy thin films agree with known bulk values (300 G), but found a remarkable eight times increase of the out-of-plane coercive fields (˜2,500 G). To explain this, we measured the switching fields between in-plane and out-of-plane thin film directions which revealed that the Kondorsky model of 180° domain wall reversal was responsible for Vicalloy's enhanced out-of-plane coercive field and possibly its permanent magnetic properties. The Kondorsky model suggests that domain-wall pinning is the origin of Vicalloy's permanent magnetic properties, in contrast to strain, shape, or

  15. Forms of Rare Earth Elements in Soils:II.Differentiation of Rare Earth Elements



    The present paper deals mainly with the relationships between the distribution of rare earth elements (REE) in different forms in soils and the atomic number and with the odd-even phenomenon in the distribution of ionic lanthanides in soils.The enrichment tendency of light REE relative to heavy REE in soils was pointed out on the experimental results about the proportions of Ce-group and Y-group elements in different REE forms in soils.Meanwhile,the differentiation of Tm in different soil REE forms was compared and the reasons why Tm is enriched in soils were preliminarily discussed.

  16. Effects of beryllium and iron additions on iron-bearing phase in A357 aluminum alloys

    Chen Zhongwei


    Full Text Available Iron is the most deleterious impurity in the Al-Si-Mg casting alloys and can easily form inter-metallic compounds that can significantly affect the subsequent behavior of material properties. Using differential scanning calorimetry (DSC and microstructural analysis, how the Be and Fe additions affect the iron-bearing phase in A357 alloys was investigated. The results show that the iron-bearing phase in A357 alloy comprises mainly the plate-like β-Al5FeSi and a small quantity of the script-type π-Al8FeMg3Si6; and that the plate-like β-Al5FeSi proportion increases with increasing iron content in the alloy. The iron-bearing phase is mostly transformed from the plate-like β-Al5FeSi to the script-type π-Al8FeMg3Si6 with the addition of Be in the alloy. The hardness of alloy samples was also tested. The results show that both the increasing iron content and Be content can increase the hardness of the alloy. This may be contributed to the change of morphology and distribution of the iron-bearing phase in A357 alloy with the addition of iron or Be to the alloy.

  17. Production technique of vermicular graphite iron cylinder head of vehicle diesel engine

    Zhou Gen


    Full Text Available The 25 years’production and application have proved that vermicular graphite iron cylinder heads with vermicularity ≥50% satisfy the machinability and performance demand of diesel engine. The method, in which using cupola-induction furnace duplex melting and pour-over process with rare earth-ferrosilicon or rare earthsilicon compound as vermicularizing alloy plus rare earth-magnesium-ferrosilicon as stirring alloy, is an optimal vermicularizing process for obtaining satisfi ed vermicularity. Using top kiss risers, enlarging kissing areas and expanding covering width and making ingates to freeze earlier are the effective measures to eliminate shrinkage, blowhole and oxide inclusions in the vermicular graphite iron cylinder heads.

  18. Rare Earth Elements in Global Aqueous Media

    Noack, C.; Karamalidis, A.; Dzombak, D. A.


    We are examining the occurrence and abundance of rare earth elements (REE) associated with produced waters from shale gas development, and factors controlling aqueous REE concentrations in geochemical environments, to provide information for: (1) potential recovery of REE as a valuable byproduct, and (2) utilization of unique REE signatures as a risk assessment tool. REE include the lanthanide series of elements - excluding short-lived, radioactive promethium - and yttrium. These elements are critical to a wide variety of high-tech, energy efficient applications such as phosphors, magnets, and batteries. Escalating costs of REE resulting from divergent supply and demand patterns motivates the first goal. The second goal relates to the search for a reliable, naturally occurring tracer to improve understanding of fluid migration and water-rock interactions during hydraulic fracturing and natural gas recovery. We compiled data from 100 studies of REE occurrence and concentrations in groundwaters, ocean waters, river waters, and lake waters. In the groundwater systems documented, total dissolved REE concentrations ranged over eight orders of magnitude; however the average concentrations across the lanthanides varied by less than two orders of magnitude. This leads to exceptional inter-element correlations, with a median correlation coefficient greater than 0.98, implying potential usefulness of REE ratios for groundwater signatures. Reports describing reactions governing REE solubilization were also investigated. We assembled information about important solution chemistries and performed equilibrium modeling using PHREEQC to examine common hypotheses regarding the factors controlling REE compositions. In particular, effects of pH, Eh, and common complexing ligands were evaluated. Produced and connate waters of the Marcellus shale are well characterized for their major chemical elements. There is a dearth of knowledge, however, regarding the occurrence of REE in

  19. Bright nickel plating on surface of machinable zinc-copper-magnesium-aluminum-rare earth zinc alloy%易切削锌-铜-镁-铝-稀土锌合金表面电镀光亮镍

    周宏明; 肖来荣; 刘芙蓉; 李艳芬


    以新型易切削Zn-Cu-Mg-Al-RE锌合金为基体,电镀得到光亮镍镀层.其工艺流程主要包括化学除油、活化、预镀镍、光亮镀镍和干燥.研究了温度、pH、电流密度、电镀时间等工艺条件对在以硫酸镍、氯化镍、硼酸和光亮剂为主要成分的镀液中所得光亮镍镀层外观的影响.电镀光亮镍的最佳工艺为:0.045~0.050A/cm2,40~45℃,pH=3.9~4.1,10min.在最佳工艺下得到的镀层总厚度约为80 μm,镀层光滑、致密、光泽度好,无针孔、麻点、起泡等缺陷,与基体结合紧密,界面存在ZnNi过渡层.%Bright nickel coating was electroplated on Zn-Cu-Mg-Al-RE zinc alloy substrate through the following process flow: chemical degreasing, activating, nickel pre-plating, bright nickel plating, and drying. The effects of temperature, pH, current density and plating time on the appearance of bright nickel coating prepared from a bath mainly composed of nickel sulfate, nickel chloride, boric acid, and brightener were studied. The optimal process parameters for bright nickel plating are as follows: 0.045-0.050 A/cm2, 40-45℃, pH 3.9-4.1, and 10 min. The coating with a thickness of ca.80 um is obtained under the optimal parameters, which is smooth, compact and of good glossiness, without defects such as pinholes, pits, and bubbles. The nickel coating is tightly bonded to zinc alloy substrate, and there is a ZnNi transition layer close to the zinc alloy substrate.

  20. Rare earth element enrichment using membrane based solvent extraction

    Makertiharta, I. G. B. N.; Dharmawijaya, P. T.; Zunita, M.; Wenten, I. G.


    The chemical, catalytic, electrical, magnetic, and optical properties of rare earth elements are required in broad applications. Rare earth elements have similar physical and chemical properties thus it is difficult to separate one from each other. Rare earth element is relatively abundant in earth's crust but rarely occur in high concentrated deposits. Traditionally, ion-exchange and solvent extraction techniques have been developed to separate and purify single rare earth solutions or compounds. Recently, membrane starts to gain attention for rare earth separation by combining membrane and proven technologies such as solvent extraction. Membrane-based process offers selective, reliable, energy efficient and easy to scale up separation. During membrane-based separation process, one phase passes through membrane pores while the other phase is rejected. There is no direct mixing of two phases thus the solvent loss is very low. Membrane can also lower solvent physical properties requirement (viscosity, density) and backmixing, eliminate flooding phenomenon and provide large interfacial area for mass transfer. This paper will summarize research efforts in developing membrane technology for rare earth element separation. Special attention will be given to solvent extraction related process as the commonly used method for rare earth element separation. Furthermore, membrane configuration and its potentials will also be discussed.

  1. Bioleaching of rare earth elements from monazite sand.

    Brisson, Vanessa L; Zhuang, Wei-Qin; Alvarez-Cohen, Lisa


    Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Paecilomyces spp. strain WE3-F. Although monazite also contains the radioactive element Thorium, bioleaching by these fungi preferentially solubilized rare earth elements over Thorium, leaving the Thorium in the solid residual. Adjustments in growth media composition improved bioleaching performance measured as rare earth release. Cell-free spent medium generated during growth of A. terreus strain ML3-1 and Paecilomyces spp. strain WE3-F in the presence of monazite leached rare earths to concentrations 1.7-3.8 times those of HCl solutions of comparable pH, indicating that compounds exogenously released by these organisms contribute substantially to leaching. Organic acids released by the organisms included acetic, citric, gluconic, itaconic, oxalic, and succinic acids. Abiotic leaching with laboratory prepared solutions of these acids was not as effective as bioleaching or leaching with cell-free spent medium at releasing rare earths from monazite, indicating that compounds other than the identified organic acids contribute to leaching performance.

  2. [Content of rare earth elements in wild Hypericum japonicum Thunb].

    Wei, Zhen-Lin; Rui, Yu-Kui; Tian, Zhi-Huan


    Rare earth elements are important nutritional elements for human health, and today more and more attention has been paid to the effective components in Chinese traditional medicine, especially to rare earth elements. Fifteen rare earth elements in wild hypericum japonicum Thunb were analyzed by the methods of ICP-MS. The results showed that the concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu and Y ranged from 6 ng x g(-1) x DW to 14 522 ng x g(-1) x DW, and among them the concentrations of La, Ce and Nd were higher than 2 000 ng x g(-1) x DW. Compared with the concentration of rare earth elements in rice, corn, wheat and barley, the total concentration of rare earth elements in hypericum japonicum Thunb was much higher, which could be the mechanism of curative effect of hypericum japonicum Thunb on liverish diseases. The character of elements and the content of rare earth elements in soil should be responsible for the difference, but the distributive mechanism of rare earth elements in hypericum japonicum Thunb should be further studied.

  3. Study on Competitive Power of Rare Earth Industry in China

    Qian Jiuhong; Li Guoping


    China is abundant of rare earth resources, it has been the biggest producer, consumer and supplier. The superiority and the scale within the last 40 years make it possible to develop China's rare earth industry in a higher degree.But the superiority of rare earth resources has not turned into the economic superiority, and the development of rare earth industry in China with high speed does not lead to high benefits. Therefore, it has become the hot point and vital task now how to resolve the main problems of rare earth industry in China and how to make its rare earth industry grow healthily and steadily through transforming resources, adjusting structure, escalating industry, bringing forth new ideas in technology. This article aims at analyzing the competitive power of China's rare earth industry in the application of "Diamond framework, Determinants of National Advantage" written by Michael Porter, the well-known economist,based on the analysis, the author puts forward a strategic proposal to raise the competitive power.

  4. Effect of Rare Earth Elements Burning Loss on Microstructure and Properties in TbDyFe

    DENG Zhong-hua


    Full Text Available In order to simulate low vacuum experimental environment,Tb0.27Dy0.73Fe1.91 alloy round bars were prepared through melting with Tb, Dy and Fe elements, directional solidification and heat treatment in low vacuum environment. The magnetostriction of the alloy rods was tested. The microstructures and the causes of defects in the alloy were investigated. The results indicate that under the low vacuum experimental environment, there are plenty of twin dendritic lamellar microstructures and ordinary twin microstructures are generated in alloy, among which the mechanical properties and "jump" effect of twin dendritic lamellar structures are good, while the ordinary twins are bad to the magnetostrictive property in the alloy. REFe2 and REFe3 coupling phase is the main phase in the matrix, the burning loss of rare earth elements lead variations in chemical composition, resulting coupling growth with REFe3 phase and REFe2 phase. The thermal stress and the burning loss of rare earth elements segregate at grain boundaries resulting in the presence of micro-cracks and micro-holes. These microstructures and defects generate bad impact on mechanical properties and magnetostriction of TbDyFe alloy rods.

  5. Continental shelves as potential resource of rare earth elements.

    Pourret, Olivier; Tuduri, Johann


    The results of this study allow the reassessment of the rare earth elements (REE) external cycle. Indeed, the river input to the oceans has relatively flat REE patterns without cerium (Ce) anomalies, whereas oceanic REE patterns exhibit strong negative Ce anomalies and heavy REE enrichment. Indeed, the processes at the origin of seawater REE patterns are commonly thought to occur within the ocean masses themselves. However, the results from the present study illustrate that seawater-like REE patterns already occur in the truly dissolved pool of river input. This leads us to favor a partial or complete removal of the colloidal REE pool during estuarine mixing by coagulation, as previously shown for dissolved humic acids and iron. In this latter case, REE fractionation occurs because colloidal and truly dissolved pools have different REE patterns. Thus, the REE patterns of seawater could be the combination of both intra-oceanic and riverine processes. In this study, we show that the Atlantic continental shelves could be considered potential REE traps, suggesting further that shelf sediments could potentially become a resource for REE, similar to metalliferous deep sea sediments.

  6. Rare earth elements exploitation, geopolitical implications and raw materials trading

    Chemin, Marie-Charlotte


    Rare earth elements (REE) correspond to seventeen elements of the periodic table. They are used in high technology, cracking, electric cars' magnet, metal alloy for batteries, and also in phone construction or ceramics for electronic card. REEs are an important resource for high technology. This project targets 16 years old students in the subject "personalized aid" and will last six weeks. The purpose of this project is to develop autonomy and research in groups for a transdisciplinary work. This project gathers knowledge in geology, geography and economics. During the first session students analyze the geology applications of the REE. They begin the analysis with learning the composition in different rocks such as basalt and diorite to make the link with crystallization. Then they compare it with adakite to understand the formation of these rocks. In the second session, they study REE exploitation. We can find them as oxides in many deposits. The principal concentrations of rare earth elements are associated with uncommon varieties of igneous rocks, such as carbonatites. They can use Qgis, to localize this high concentration. In the third session, they study the environmental costs of REE exploitation. Indeed, the exploitation produces thorium and carcinogenic toxins: sulphates, ammonia and hydrochloric acid. Processing one ton of rare earths produces 2,000 tons of toxic waste. This session focuses, first, on Baotou's region, and then on an example they are free to choose. In the fourth session, they study the geopolitical issues of REE with a focus on China. In fact this country is the largest producer of REE, and is providing 95% of the overall production. REE in China are at the center of a geopolitical strategy. In fact, China implements a sort of protectionism. Indeed, the export tax on REE is very high so, as a foreign company, it is financially attractive to establish a manufacturing subsidiary in China in order to use REE. As a matter of fact

  7. Advances on Rare Earth Application in Pollution Ecology

    Huang Xiaohua; Zhou Qing; Zhang Guangsheng


    The use of rare earth for inducing plant resistance was reviewed. The important developments in recent years were described, and rare earth can alleviate the pollution of acid rain, ozone, pesticide, heavy metals etc. in environment. The authors suggest that the mechanism of rare earth to inducing plant resistance and reducing plant injury is to control biochemical metabolism web in plant cell, to adjust its protection system of free radical, to maintain its photosynthesis, to protect cell membrane system and to carry through its function on mineral metabolism. Meanwhile some problems in the field were discussed as well.

  8. Review and forecast of China rare earth industry (continued)


    @@ 3. Current rare earth export situation a. RE export enterprises To further strengthen administration on export of rare earths and standardize export system, the Ministry of Commerce instituted the "Qualification Standards and Application Procedures for Rare Earth Export Enterprises" in 2006, which regulated the export from production capacity, technologies, safety & environmental protection and credit of enterprises, hence to standardize the export system. There were 47 RE export enterprises announced in common trade in 2006, while it dropped to 41 ones in 2007 and 25 in 2008. There were merely 23 export enterprises in 2009.

  9. Geochemistry of Rare Earth Elements in Aktishikan Gold Deposit, Xinjiang

    袁峰; 周涛发; 岳书仓


    The characteristics and the models of rare earth elements in the geolo gical bodies and the hydrothermal water balanced with the adamellite were compre h ensively studied in Aktishikan gold deposit,Nurt area of Altay,Xinjiang.And th e behavior of rare earth elements during metasomatic alteration was discussed by using the isocon method of Grant.The results show that the rare earth elements a re inert during metasomatic alteration,the hydrothermal water has no relation t o the magmatic water,and the gold material sources mainly stem from the wall rock.

  10. Thermal Oxidation Resistance of Rare Earth-Containing Composite Elastomer

    邱关明; 张明; 周兰香; 中北里志; 井上真一; 冈本弘


    The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found that its retention rate of mechanical properties is far higher than that of the control sample. The results of thermogravimetric analysis show that its thermal-decomposing temperature rises largely. The analysis of oxidation mechanisms indicates that the main reasons for thermal oxidation resistance are that rare earth elements are of the utility to discontinue autoxidation chain reaction and that the formed complex structure has steric hindrance effect on oxidation.

  11. Separation of rare earth elements by tertiary pyridine type resin

    Suzuki, Tatsuya [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)]. E-mail:; Itoh, Keisuke [Graduate School of Material Science and Engineering, Shibaura Institute of Technology, Shibaura, Minato-ku, Tokyo 108-8584 (Japan); Ikeda, Atsushi [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Aida, Masao [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Ozawa, Masaki [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Oarai Engineering Center, Japan Nuclear Cycle Development Institute, Narita-machi, Oarai-machi, Higashiibaraki-gun, Ibaraki 311-1393 (Japan); Fujii, Yasuhiko [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)


    The novel separation method of rare earth elements by using the tertiary pyridine type resin with methanol and nitric acid mixed solution was developed. The separating operation in this method is very simple and easy, and the waste generation in this method is expected to be low. The adsorption and separation behaviors of rare earth elements were investigated with changing the nitric acid concentration, the methanol concentration, and the alcoholic species. It was confirmed that the rare earth elements can be well separated mutually.

  12. The austempering study of alloyed ductile iron

    Eric, Olivera [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11001 Belgrade (Serbia and Montenegro)]. E-mail:; Jovanovic, Milan [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11001 Belgrade (Serbia and Montenegro); Sid-baranin, Leposava [University of Novi Sad, Faculty of Technical Sciences, Novi Sad (Serbia and Montenegro); Rajnovic, Dragan [University of Novi Sad, Faculty of Technical Sciences, Novi Sad (Serbia and Montenegro); Zec, Slavica [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11001 Belgrade (Serbia and Montenegro)


    Austempered ductile iron (ADI) proved to be an excellent material as it possesses attractive properties: high strength, ductility and toughness are combined with good wear resistance and machinability. These properties can be achieved upon adequate heat treatment which yields optimum microstructure for a given chemical composition. In this paper an investigation has been conducted on ADI alloyed with 0.45%Cu and austempered in a range of times and temperatures. The microstructure and fracture mode developed throughout these treatments have been identified by means of light and scanning electron microscopy and X-ray diffraction analysis. It was shown that strength, elongation and impact energy strongly depend on amounts of bainitic ferrite and retained austenite. Based on these results an optimal processing window has been established.

  13. Multilayer Thermal Barrier Coating (TBC) Architectures Utilizing Rare Earth Doped YSZ and Rare Earth Pyrochlores

    Schmitt, Michael P.; Rai, Amarendra K.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.


    To allow for increased gas turbine efficiencies, new insulating thermal barrier coatings (TBCs) must be developed to protect the underlying metallic components from higher operating temperatures. This work focused on using rare earth doped (Yb and Gd) yttria stabilized zirconia (t' Low-k) and Gd2Zr2O7 pyrochlores (GZO) combined with novel nanolayered and thick layered microstructures to enable operation beyond the 1200 C stability limit of current 7 wt% yttria stabilized zirconia (7YSZ) coatings. It was observed that the layered system can reduce the thermal conductivity by approximately 45 percent with respect to YSZ after 20 hr of testing at 1316 C. The erosion rate of GZO is shown to be an order to magnitude higher than YSZ and t' Low-k, but this can be reduced by almost 57 percent when utilizing a nanolayered structure. Lastly, the thermal instability of the layered system is investigated and thought is given to optimization of layer thickness.


    F.S. Chen; Y.X. Liu; D.K. Liang; L.M. Xiao


    The microstructure of plasma nitrided layer catalyzed by rare-earth elements has beenstudied with TEM. The results show that the grains of γ'-Fe4N phase are refinedby rare-earth elements and the plane defects in boundary are increased by rare-earthelements. The addition of rare-earth element increases the bombardment effect andthe number of crystal defects such as vacancies, dislocation loops, twins and stackingfaults in γ'-Fe4N phase and can produce the high-density dislocations in the ferrite ofdiffusion layer at a distance 0. 08mm from the surface. The production of a numberof crystal defects is one of important reasons why rare-earth element accelerates thediffusion of nitrogen atoms during plasma-nitridiug.

  15. Monolithic Rare Earth Doped PTR Glass Laser Project

    National Aeronautics and Space Administration — The main goal of the project is to demonstrate the feasibility of a monolithic solid state laser on the basis of PTR glass co-doped with luminescent rare earth ions....

  16. Rare earths: Market disruption, innovation, and global supply chains

    Eggert, Roderick; Wadia, Cyrus; Anderson, Corby; Bauer, Diana; Fields, Fletcher; Meinert, Lawrence D.; Taylor, Patrick


    Rare earths, sometimes called the vitamins of modern materials, captured public attention when their prices increased more than ten-fold in 2010 and 2011. As prices fell between 2011 and 2016, rare earths receded from public view—but less visibly they became a major focus of innovative activity in companies, government laboratories and universities. Geoscientists worked to better understand the resource base and improve our knowledge about mineral deposits that will be mines in the future. Process engineers carried out research that is making primary production and recycling more efficient. Materials scientists and engineers searched for substitutes that will require fewer or no rare earths while providing properties comparable or superior to those of existing materials. As a result, even though global supply chains are not significantly different now than they were before the market disruption, the innovative activity motivated by the disruption likely will have far-reaching, if unpredictable, consequences for supply chains of rare earths in the future.

  17. Prospects for trivalent rare earth molecular vapor lasers for fusion

    Krupke, W.F.


    The dynamical properties of three types of RE/sup 3 +/ molecular vapors were considered: (1) rare earth trihalogens, (2) rare earth trihalogens complexed with transition metal trihalogens, and (3) rare earth chelates. Radiative and nonradiative (unimolecular and bimolecular) transition probabilities have been calculated using phenomenological models predicted on the unique electronic structure of the triply ionized RE ion (well shielded ground electronic configuration of equivalent of electrons). Although all the lanthanide ions have been treated in some detail, specific results are presented for the Nd/sup 3 +/ and Tb/sup 3 +/ ions to illustrate the systematics of these vapors as a class of new laser media. Once verified, these phenomenological models will provide a powerful tool for the directed experimental exploration of these systems. Because of the structural similarity to the triply ionized actinides, comments offered here for the lanthanide rare earth series generally apply to gaseous actinide lasers which are also under consideration.

  18. Synthesis of Polyketone STCO Promoted by Rare Earth Catalyst

    GUO Jintang; ZHENG Yonghui; WANG Bo; TIAN Jing


    To lower the cost of polyketone synthesis, rare earth coordinate catalyst was introduced to the copolymerization of carbon monoxide (CO) and styrene (ST) to synthesize aliphatic polyketone STCO.The catalytic system was composed of rare earth neodymium acetate, yttrium acetate,2,2'-bipyridine, p-toluensulfonic acid, cupric p-toluensulfonate, and 1,4-benzoquinone.The catalyst and the copolymer were characterized by infrared spectrum and X-ray photoelectron spectroscopy respectively.The effects of each component of catalytic system and the kinds of rare earth acetates on catalytic activity of copolymerization were investigated.The results show that the proposed rare earth has distinct catalytic activity in the copolymerization of CO and ST and the maximum activity can reach 303.3 gSTCO/(mol·h).

  19. Rare Earth Market Review August 20-31


    @@ Rare earth market still went downward affected by continuous price fall of didymium oxide and didymium mischmetal. However, the market of europium oxide (99.99%) remained stable, with price rose slightly.

  20. Rare Earth Doped Optical Fibre From Oxide Nanoparticles

    Minati Chatterjee; Aharon Gedanken; Renata Reisfeld; Ranjan Sen; Mrinmay Pal; Milan Naskar; Mukul Paul; Shyamal Bhadra; Kamal Dasgupta; Dibyendu Ganguli; Tarun Bandyopadhyay


    Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control over RE incorporation and homogeneity in the preform.

  1. Rare Earth Doped High Temperature Ceramic Selective Emitters

    Chubb, Donald L.; Pal, AnnaMarie; Patton, Martin O.; Jenkins, Phillip P.


    As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study develops a spectral emittance model for films of rare earth containing materials. Although there are several possible rare earth doped high temperature materials, this study was confined to rare earth aluminum garnets. Good agreement between experimental and theoretical spectral emittances was found for erbium, thulium and erbium-holmium aluminum garnets. Spectral emittances of these films are sensitive to temperature differences across the film. Emitter efficiency is also a sensitive function of temperature. For thulium aluminum garnet the efficiency is 0.38 at 1700 K but only 0.19 at 1262 K.

  2. China vows equal treatment in rare earth regulation


    BEIJING, July 15 (Xinhua)-- China pledged it will abide by World Trade Organization rules and apply "same policies" to both domestic and overseas companies in rare earth production, processing and export.

  3. Thermal Stability and Proton Conductivity of Rare Earth Orthophosphate Hydrates

    Anfimova, Tatiana; Li, Qingfeng; Jensen, Jens Oluf


    Hydrated orthophosphate powders of three rare earth metals, lanthanum, neodymium and gadolinium, were prepared and studied as potential proton conducting materials for intermediate temperature electrochemical applications. The phosphates undergo a transformation from the rhabdophane structure...

  4. Prospects for Non-Rare Earth Permanent Magnets for Traction Motors and Generators

    Kramer, M. J.; McCallum, R. W.; Anderson, I. A.; Constantinides, S.


    With the advent of high-flux density permanent magnets based on rare earth elements such as neodymium (Nd) in the 1980s, permanent magnet-based electric machines had a clear performance and cost advantage over induction machines when weight and size were factors such as in hybrid electric vehicles and wind turbines. However, the advantages of the permanent magnet-based electric machines may be overshadowed by supply constraints and high prices of their key constituents, rare earth elements, which have seen nearly a 10-fold increase in price in the last 5 years and the imposition of export limits by the major producing country, China, since 2010. We outline the challenges, prospects, and pitfalls for several potential alloys that could replace Nd-based permanent magnets with more abundant and less strategically important elements.

  5. Study on Co-Permeation of Solid Rare Earth, Boron and Vanadium

    陶小克; 董桂霞; 彭日升; 孙永昌


    The effect of rare earth compound of CeCl3 on the kinetic process, composition, microstructure and mechanical properties of co-permeating of solid powder boron-vanadium (B-V) was investigated. The results indicate that the addition of CeCl3 to permeating agent not only has obviously catalytic effect on permeating rate, which increases by more than 40%, but also greatly improves the hardness and abrasion resistant of the permeating layer owing to the formation of new phase of CeFe2 after Ce permeates into the layer of the part as an alloying ingredient. It is believed that rare earth elements accelerate the permeating rate of B and V by increasing the potentials of B and V of the agent, activating the surface of the workpiece, and decreasing the activation energy of diffusion of the B and V atoms.

  6. Rare-earth loaded liquid scintillator (for LENS experiment)

    Barabanov, I R; Kornoukhov, V N; Yanovich, E A; Zatsepin, G T; Danilov, N A; Korpusov, G V; Kostukova, G V; Krylov, Y S; Yakshin, V V


    Rare-earth (Yb/Gd) complexes with neutral organophosphorus ligands are briefly discussed for their application in liquid scintillation technique. To evaluate the principal feasibility of rare-earth loaded scintillator, the ytterbium chloride complexes with tri-isoamylphosphine oxides were synthesized. Relative scintillation efficiency (RSE) for two Yb concentrations (78 and 88 g/L) was measured by means of the internal conversion exitation from Cs-137. The results obtained were 50 and 40% respectively.

  7. Rare Earth-Activated Silica-Based Nanocomposites

    C. Armellini


    Full Text Available Two different kinds of rare earth-activated glass-based nanocomposite photonic materials, which allow to tailor the spectroscopic properties of rare-earth ions: (i Er3+-activated SiO2-HfO2 waveguide glass ceramic, and (ii core-shell-like structures of Er3+-activated silica spheres obtained by a seed growth method, are presented.



    Remarkable improvements have been made on the crystal growth of rare earth pnictides and chalchogenides by the development of new growth technique and the construction of several new equipments for the crystal growth such as electron beam welding system of tungsten crucible provided with large glove box and vacuum HF furnace. This system has really worked on obtaining excellent quality of single crystals and made easier to explore unknown materials of rare earth compounds. Interesting and att...

  9. Rare-earth-ion-doped double-tungstate waveguides

    Pollnau, M.


    It has been recognized that the monoclinic double tungstates KY(WO4)2, KGd(WO4)2, and KLu(WO4)2 possess a high potential as rare-earth-ion-doped solid-state laser materials, partly due to the high absorption and emission cross-sections of rare-earth ions when doped into these materials. Besides, the

  10. Application progress of rare earth nano-materials

    Xiao Zhe


    @@ Total rare earth consumption exceeded 72,600 tREO domestically in China in 2007, among which over 38,500 tREO were consumed in functional materials like permanent magnetic materials, fluorescent materials, hydrogen storage materials, catalytic materials and polishing powders,representing 53% of total RE consumption. Production and application of RE performance materials have been the main force promoting the development of China rare earth industry.

  11. Determination of rare earth elements in plant protoplasts by MAA


    A preliminary study on the speciation of rare earth elements in plant cells has been carried out by molecular activation analysis (MAA). Mesophyll protoplasts of Brassica napus were isolated by enzymatic digestion. After being washed with isosmotic solution containing EDTA for several times, the protoplasts were purified by gradient centrifugation. Then the concentration of rare earth elements (REEs) in the protoplasts was determined by neutron activation analysis. The result shows that REEs can enter the cells of the plant.

  12. On ultra dispersed statuses iron-graphitic of alloys


    @@ On the basis of the new theory of graphite formation at hardening iron alloys are developed and the ways of manufacturing of iron alloys with ultra-dispersed by structure of carbon are experimentally tested.The ways are based on preliminary creation in smelt of uncontinuities, which surface at hardening becomes covered by a film of free carbon lowering power expenses for formation inter phases of surfaces.

  13. On ultra dispersed statuses iron-graphitic of alloys

    Baranov; D.; A.; Baranov; A.; A.


    On the basis of the new theory of graphite formation at hardening iron alloys are developed and the ways of manufacturing of iron alloys with ultra-dispersed by structure of carbon are experimentally tested.The ways are based on preliminary creation in smelt of uncontinuities, which surface at hardening becomes covered by a film of free carbon lowering power expenses for formation inter phases of surfaces.……

  14. Current Status on Resource and Recycling Technology for Rare Earths

    Takeda, Osamu; Okabe, Toru H.


    The development of recycling technologies for rare earths is essential for resource security and supply stability because high-quality rare earth mines are concentrated in China and the demand for rare earth metals such as neodymium and dysprosium, used as raw materials in permanent magnets (neodymium magnet), is expected to increase rapidly in the near future. It is also important to establish a recycling-based society from the perspective of the conservation of finite and valuable mineral resources and the reduction of the environmental load associated with mining and smelting. In this article, the current status of rare earth resource as well as that of recycling technology for the magnets is reviewed. The importance of establishing an efficient recycling process for rare earths is discussed from the characteristics of supply chain of rare earths, and the technological bases of the recycling processes for the magnet are introduced. Further, some fundamental researches on the development of new recycling processes based on pyrometallurgical process are introduced, and the features of the recycling processes are evaluated.

  15. Corrosion of metastable iron alloys in aqueous solutions

    Wolf, Gerhard K.; Ferber, H.


    There exist some examples showing that metastable surface alloys can modify the corrision properties of a substrate in the same way as stable alloys do. In the present paper the corrosion behaviour of metastable surface alloys obtained by implanting gold, lead and mercury in iron was studied in aqueous solution of pH = 5.6. Potentiodynamic current density-potential curves were recorded of the implanted samples without further treatment and after isothermal annealing to temperatures up to 800°C. The results were compared with structural information on the alloys obtained by Turos et al. with α-backscattering and channeling experiments. Gold implantation turned out to enhance the active corrosion rate of iron, while lead and mercury had an impeding effect. The annealing experiments showed that the surface alloying facilitated the passivation of iron as long as the substitutional solid solution was "(meta)stable". After the breakdown at higher annealing temperatures leading to surface migration and clustering of the implanted elements a significant increase of the critical current density for passivation took place. This indicates passivation difficulties caused by the heterogeneous distribution of the "alloying" particles. In general the results suggest that substitutional metastable iron alloys cause in a systematic way corrosion inhibition or enhancement. However, their corrosion properties may change completely for non-substitutional distribution of the alloying elements as originating from annealing at higher temperatures.

  16. Distribution of Rare Earth Metals in Technogenic Wastes of Energy Enterprises (Results of the Laboratory Studies

    Alexandr Ivanovich Khanchuk


    Full Text Available The results of the research interaction between ash and slag samples from Vladivostok TPP’s landfills saturated with underburning and ammonium hydrodifluoride were given. It was found out that the reactions of the main components of a concentrate with NH4HF2 are flowing with creation of complex ammonium fluoro-metalate. It is shown that the distribution of REM (rare earth metals between foam and heavier products is going during the flotation process of carbon-containing ash and slag samples without significant concentrating. It is shown that the water leaching of fluoridated product lets transfer silicone, aluminum and iron salts into solution and concentrate rare earth elements in insoluble residue in the form of complex salts of NaLnF4 general formula. We propose a schematic diagram of hydrodifluoride recycling of carbon-containing sample, which provides concentrating of REM with incomplete separation of macro-components.

  17. Commercial Reserve will Help Rare Earth Industry to Leave Behind Cold Winter


    As key component in the construction of rare earth strategy reserve system,the rare earth commercial reserve,an initiative advocated by the state government,spontaneously carried out by several major rare earth enterprise groups to target at reform of the supply front for the rare earth industry,formally kicked off.The encouraging news is that,within a matter of one month,affected by news of rare earth commercial reserve,rare earth market prices

  18. Advanced Characterization of Rare Earth Elements in Coal Utilization Byproducts

    Verba, C.; Scott, M.; Dieterich, M.; Poston, J.; Collins, K.


    Rare earth elements (REE) in various forms (e.g., crystalline mineral phases; adsorbed/absorbed state on and into organic macerals, neoformed glass from flyash or bottom ash) from domestic feedstocks such as coal deposits to coal utilization byproducts (CUB) have the potential to reduce foreign REE dependence and increase domestic resource security. Characterization is critical for understanding environmental risks related to their fate and transport as well as determining the most practical and economical techniques for concentrating the REE and converting them into chemical stocks for manufacturing. Several complementary electron microscopy (SEM-EDS, EPMA-WDS, FIB-SEM, cathodoluminescence, and XRD) and post image processing techniques were used to understand REE transition from coal to CUB. Sites of interest were identified and imaged and respective elemental x-ray maps acquired and montaged. Pixel classification of SEM imagers was completed using image analysis techniques to quantify the distribution of REE associated features. Quantitative elemental analysis of phases were completed using EMPA-WDS followed by FIB-SEM. The FIB-SEM results were reconstructed into 3D volumes and features of interest (e.g. monazite) were analyzed to determine the structure and volumetric estimation of REEs and thus predict detrital REE phases to ICP-MS results. Trace minerals were identified as pyrite, zircon, REE-phosphates' (monazite, xenotime), and barite within the coal tailings. In CUB, amorphous aluminosilicates, iron oxide cenospheres, and calcium oxides were present; monazite appear to be unaltered and unaffected by the combustion process in these samples. Thermal decomposition may have occurred due to presence of detrital zircon and xenotime and subsequent thin Ca-oxide coating enriched in trace REEs.

  19. Interaction between alloying and hardening of cast iron surface

    刘政军; 郝雪枫; 傅迎庆; 牟力军


    To improve wear resistance of surface will increase the service life of gray cast iron directly. This paper presents that gray cast iron surface coated with alloy powder is locally remelted by TIG arc to increase the wear resistance. The influences of arc current and scanning rate etc on surface properties are found. Under different conditions, the microstructure, hardness and wear resistance of remelted layer are analyzed and measured. The results indicate that the gray cast iron surface can be strengthened by TIG arc local remelting treatment. Especially, surface alloying hardening effect is best and surface properties are improved remarkably.

  20. Iron aluminide alloy container for solid oxide fuel cells

    Judkins, Roddie Reagan (Knoxville, TN); Singh, Prabhakar (Export, PA); Sikka, Vinod Kumar (Oak Ridge, TN)


    A container for fuel cells is made from an iron aluminide alloy. The container alloy preferably includes from about 13 to about 22 weight percent Al, from about 2 to about 8 weight percent Cr, from about 0.1 to about 4 weight percent M selected from Zr and Hf, from about 0.005 to about 0.5 weight percent B or from about 0.001 to about 1 weight percent C, and the balance Fe and incidental impurities. The iron aluminide container alloy is extremely resistant to corrosion and metal loss when exposed to dual reducing and oxidizing atmospheres at elevated temperatures. The alloy is particularly useful for containment vessels for solid oxide fuel cells, as a replacement for stainless steel alloys which are currently used.

  1. Application of Rare Earths in Thermal Barrier Coating Materials

    Xueqiang CAO


    Rare earths are a series of minerals with special properties that make them essential for applications including miniaturized electronics, computer hard disks, display panels, missile guidance, pollution controlling catalysts,H2-storage and other advanced materials. The use of thermal barrier coatings (TBCs) has the potential to extend the working temperature and the life of a gas turbine by providing a layer of thermal insulation between the metallic substrate and the hot gas. Yttria (Y2O3), as one of the most important rare earth oxides, has already been used in the typical TBC material YSZ (yttria stabilized zirconia). In the development of the TBC materials, especially in the latest ten years, rare earths have been found to be more and more important. All the new candidates of TBC materials contain a large quantity of rare earths, such as R2Zr2O7 (R=La, Ce, Nd,Gd), CeO2-YSZ, RMeAI11O19 (R=La, Nd; Me=Mg, Ca, Sr) and LaPO4. The concept of double-ceramiclayer coatings based on the rare earth materials and YSZ is effective for the improvement of the thermal shock life of TBCs at high temperature.

  2. Alleviation Effects of Rare Earth on Cd Stress to Rape

    马建军; 张淑侠; 朱京涛; 吴贺平


    Using rapes as test materials, the fastness expression and alleviation effect of rapes were studied under Cd stress condition, as the rapeseeds were dipped in the single element(La, Ce, Nd, Pr)and mixed rare earth(RE). The results indicate that, under Cd stress, the dry and fresh weight are increased by both the single element and mixed rare earth treatment, and the fastness of rape is improved.The single element of rare earth decreases the Cd content in rape roots and transmits Cd to the edible parts above the ground in which the alleviation effect of Ce is most significant.La treatment takes the second place, so that the poisonous effect of heavy metal Cd is eased.The mixed rare earth doesn't alleviate the assimilation of Cd in rape roots, but accelerates the transfer of Cd to the parts above the ground. The research puts forward that the alleviation of rare earth on Cd stress has connection with the decrease of Ca content.

  3. Rare Earth Elements - A New Challenge for the World Economy

    Cristina Bumbac


    Full Text Available Rare Earth Elements or Rare Earth Metals (REM are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium and fifteen lanthanides. The term "rare earth" arises from the rare earth minerals from which they were first isolated. They are uncommon oxide-type minerals (earths found in Gandolinite extracted from one mine in Sweden. The first discovery was made in 1794, but it was only in 1940 that the scientist Frank Spedding developed an ion exchange procedure for separating and purifying the REM. For the next decades, they were hardly used in some "minor" industrial fields. Only after 2000 their importance grew, once the multitude of possibilities to use them was discovered due to technological progress. Now REM are incorporated into almost all modern technological devices: superconductors, magnets, electronic polishers, refining catalysts hybrid car components and military techniques. They are used in small quantities, but due to their extraordinary properties the prices are very high. The main problem is that China dominates this market, with 97% of total global supply. The highest concentration of rare earth metals are in Inner Mongolia in China, Mountain Pass in California U.S.A. and in Mount Weld in Australia. The developed countries are far behind China regarding production and are indeed depending on Chinese exports. Hence, there is a difficult situation on this particular market, with an uncertain future.

  4. Pulsed laser deposition of rare earth compounds

    Stone, L A


    Magnetostrictive thin films have been deposited using various techniques such as sputtering and evaporation but the use of laser deposition has been limited. This research presents the results from pulsed laser deposition (PLD) of TbFe sub 2 , DyFe sub 2 and Terfenol-D thin films using an infra red Transversely Excited Atmospheric (TEA) CO sub 2 laser at lambda approx 10.6 mu m and an ultra violet Argon-Fluoride (ArF) excimer laser at lambda approx 193 nm. Results have showed that the TEA CO sub 2 laser under the range of conditions studied is not suitable for the production of magnetostrictive films. The problems experienced are a mixture of mostly fracture debris at low fluences (F approx 20 Jcm sup - sup 2) and melt droplets at high fluences (F approx 60 Jcm sup - sup 2). In all cases the destruction of the target is a major problem, with the Terfenol-D targets being the worst affected. Thin films produced were all iron rich. The use of an excimer laser has proved more successful in providing stoichiometri...

  5. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun


    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

  6. Infrared spectroscopy of rare-earth-doped CaFe2As2

    Xing, Zhen; Huffman, T. J.; Xu, Peng; Qazilbash, M. M.; Saha, S. R.; Drye, Tyler; Paglione, J.


    Recently, rare-earth doping in CaFe2As2 has been used to tune its electronic, magnetic, and structural properties. The substitution of rare-earth ions at the alkaline-earth sites leads to the suppression of the spin-density wave (SDW) phase transition in CaFe2As2. For example, Pr substitution results in a paramagnetic metal in the tetragonal phase that is susceptible to a low temperature structural transition to a collapsed tetragonal phase. However, La-doped CaFe2As2 remains in the uncollapsed tetragonal structure down to the lowest measured temperatures. Both the uncollapsed and collapsed tetragonal structures exhibit superconductivity with maximum Tc reaching 47 K, the highest observed in inter-metallics albeit with a small superconducting volume fraction. In this work, we perform ab-plane infrared spectroscopy of rare-earth-doped CaFe2As2 at different cryogenic temperatures. Our aim is to ascertain the contributions of electron doping and chemical pressure to the charge and lattice dynamics of this iron-arsenide system.

  7. Spectroscopic properties of rare earths in optical materials

    Parisi, Jürgen; Osgood, R; Warlimont, Hans; Liu, Guokui; Jacquier, Bernard


    Aimed at researchers and graduate students, this book provides up-to-date information for understanding electronic interactions that impact the optical properties of rare earth ions in solids. Its goal is to establish a connection between fundamental principles and the materials properties of rare-earth activated luminescent and laser optical materials. The theoretical survey and introduction to spectroscopic properties include electronic energy level structure, intensities of optical transitions, ion-phonon interactions, line broadening, and energy transfer and up-conversion. An important aspect of the book lies in its deep and detailed discussions on materials properties and the potential of new applications such as optical storage, information processing, nanophotonics, and molecular probes that have been identified in recent experimental studies. This volume will be a valuable reference book on advanced topics of rare earth spectroscopy and materials science.

  8. Refining and Mutual Separation of Rare Earths Using Biomass Wastes

    Inoue, Katsutoshi; Alam, Shafiq


    Two different types of adsorption gels were prepared from biomass wastes. The first gel was produced from astringent persimmon peel rich in persimmon tannin, a polyphenol compound, which was prepared by means of simple dehydration condensation reaction using concentrated sulfuric acid for crosslinking. This adsorption gel was intended to be employed for the removal of radioactive elements, uranium (U(VI)) and thorium (Th(IV)), from rare earths. The second gel was prepared from chitosan, a basic polysaccharide, produced from shells of crustaceans such as crabs, shrimps, prawns, and other biomass wastes generated in marine product industry, by immobilizing functional groups of complexanes such as ethylendiaminetetraacetic acid and diethylentriaminepentaacetic acid (DTPA). This gel was developed for the mutual separation of rare earths. Of the two adsorption gels evaluated, the DTPA immobilized chitosan exhibited the most effective mutual separation among light rare earths.

  9. Optical Frequency Comb Spectroscopy of Rare Earth Atoms

    Swiatlowski, Jerlyn; Palm, Christopher; Joshi, Trinity; Montcrieffe, Caitlin; Jackson Kimball, Derek


    We discuss progress in our experimental program to employ optical-frequency-comb-based spectroscopy to understand the complex spectra of rare-earth atoms. We plan to carry out systematic measurements of atomic transitions in rare-earth atoms to elucidate the energy level structure and term assignment and determine presently unknown atomic state parameters. This spectroscopic information is important in view of the increasing interest in rare-earth atoms for atomic frequency standards, in astrophysical investigations of chemically peculiar stars, and in tests of fundamental physics (tests of parity and time-reversal invariance, searches for time variation of fundamental constants, etc.). We are presently studying the use of hollow cathode lamps as atomic sources for two-photon frequency comb spectroscopy. Supported by the National Science Foundation under grant PHY-0958749.

  10. Study on Microstructure of Alumina Based Rare Earth Ceramic Composite


    Analysis techniques such as SEM, TEM and EDAX were used to investigate the microstructure of rare earth reinforced Al2O3/(W, Ti)C ceramic composite. Chemical and physical compatibility of the composite was analyzed and interfacial microstructure was studied in detail. It is found that both Al2O3 and (W, Ti)C phases are interlaced with each other to form the skeleton structure in the composite. A small amount of pores and glass phases are observed inside the material which will inevitably influence the physical and mechanical property of the composite. Thermal residual stresses resulted from thermal expansion mismatch can then lead to the emergence of dislocations and microcracks. Interfaces and boundaries of different types are found to exist inside the Al2O3/(W, Ti)C rare earth ceramic composite, which is concerned with the addition of rare earth element and the extent of solid solution of ceramic phases.


    О. V. Diachenko


    Full Text Available The paper is devoted to investigations on influence of laser treatment regimes of gas-thermal and adhesive coatings from self-fluxing powders on iron basis and after melting with modifying plaster on their roughness and phase composition. One of mathematical planning methods that is a complete factor experiment method has been used for investigation of parameters’ influence on micro-geometry of coatings. The executed investigations have made it possible to observe a general regularity which does not depend on a type of alloying plaster: while increasing speed of laser beam relatively to treated part, beam diameter value of Ra parameter is becoming less. Decrease in height of surface irregularities in case of increasing laser beam speed is related with intensification of evaporation processes. An increase in beam diameter diminishes Ra parameter of the surface. This is due to the fact that decrease in power density occurs at high rate of beam defocusing. Overlapping coefficient does not exert a pronounced effect on Ra parameter of fused coatings. While increasing the speed of laser beam relatively to the part structure is transferred from dendrite into supersaturated one with carbide and boride precipitations. It has been established that technological parameters of laser treatment and particularly speed of laser beam influence on coating composition. While increasing the speed up to v5 = 5 × 10–3 m/s amount of chromium has become larger by 1.5-fold that resulted in increase of micro-hardness of the coating from 9.5–10.1 GPa up to 11.04–15.50 GPa.

  12. Structure of Rare-earth/Alkali Halide Complexes

    Akdeniz, Z.; Önem, Z. Çiçek; Tosia, M. P.


    Vapour complex formation of rare-earth halides with alkali halides strongly increases the volatility of these compounds. We evaluate the structure taken by such complexes having the chemical formulas MRX4, M2RX5 and M3RX6, where X = F or Cl and typically M = Li or Na and R = La. The roles played by the two types of metal atom is investigated in MRX4 complexes by also taking M = K, Rb or Cs and R = Gd or Lu. The main predictions that emerge from our calculations are as follows: (i) in MRX4 a fourfold coordination of the rare-earth atom is accompanied by twofold or threefold coordination of the alkali atom, the energy difference in favour of the twofold-coordination state being about 0.3 eV in the case of the LiF complexing agent but even changing sign as the ionic radius of either the alkali or the halogen is increased; (ii) in M2RX5 a fivefold coordination of the rare-earth atom is energetically more stable than a fourfold one, by again not more than about 0.3 eV; (iii) in M3RX6 the fivefold and sixfold coordinations of the rare-earth atom are energetically competitive; and (iv) in both M2RX5 and M3RX6 each coordination state can be realized in various forms that differ in detail but are close in energy. Bond fluctuations and disorder around the rare-earth atom can be expected to be a general feature at elevated temperatures, both in the vapour and in liquid rare-earth/alkali halide mixtures.

  13. Experiment on Nonlinear Properties Coupling Electromagnetism with Mechanics of Giant Rare Earth Magnetostrictive Materials

    Yuan Huiqun; Sun Huagang


    The electromagnetic and mechanical coupling properties of giant rare earth giant magnetostriction material TbxDy1 -xFe2 -z (0. 27 ≤x ≤ 0.3, 0 ≤ z ≤ 0.1 ) alloys were investigated by means of self-fabricated test apparatus. The effect of coupling mechanical with electromagnetic on magnetostrictive strain coefficient was discussed. The physical model of the coupling system was established. Based on the equivalent circuit of the coupling system, the magnetomechanical coupling coefficient was derived by means of impedance resistance analysis method.

  14. Protecting the environment and public health from rare earth mining

    Huang, Xiang; Zhang, Guochun; Pan, An; Chen, Fengying; Zheng, Chunli


    As increasing demand for green energy and high-tech devices grows, so does the rising prospecting of rare earth metals required for their production. Protecting the environment and public health from rare earth element (REE) mining as well as emerging pollutants is urgently required to achieve sustainable development. This study mapped Earth's hidden REE deposits to identify potential contamination hotspots with the aim of preventing its deleterious effects on the environment. We worry that there would be widespread tailing facilities concomitant with serious pollutions, such as the Bayan Obo tailings site, and argue that a tradeoff between the underground REE exploration and environment conservation should be reached as soon as possible.

  15. Thermal Expansion and Thermal Conductivity of Rare Earth Silicates

    Zhu, Dongming; Lee, Kang N.; Bansal, Narottam P.


    Rare earth silicates are considered promising candidate materials for environmental barrier coatings applications at elevated temperature for ceramic matrix composites. High temperature thermophysical properties are of great importance for coating system design and development. In this study, the thermal expansion and thermal conductivity of hot-pressed rare earth silicate materials were characterized at temperatures up to 1400 C. The effects of specimen porosity, composition and microstructure on the properties were also investigated. The materials processing and testing issues affecting the measurements will also be discussed.

  16. Integrated Automation System for Rare Earth Countercurrent Extraction Process

    柴天佑; 杨辉


    Lower automation level in industrial rare-earth extraction processes results in high production cost, inconsistent product quality and great consumption of resources in China. An integrated automation system for extraction process of rare earth is proposed to realize optimal product indices, such as product purity,recycle rate and output. The optimal control strategy for output component, structure and function of the two-gradcd integrated automation system composed of the process management grade and the process control grade were discussed. This system is successfully applied to a HAB yttrium extraction production process and was found to provide optimal control, optimal operation, optimal management and remarkable benefits.

  17. Imports (&) Exports Review of Chinese Rare Earths (continued)


    @@ Since 2001, China kept its position of the largest producing country of rare earth magnets in the world and worked on further in the global market. China exported 7,709 tons of rare earth magnets and earned foreign currency of US $ 214 million in 2004, increasing 37.2% and 33.0% over the same period of 2003 respectively. In 2005, China exported 8,756 tons of RE magnets and earned foreign currency of US $ 239 million, up 13.9% and 11.4% over 2004 respectively. The first six export destinations are listed in Table 3.

  18. Instability of some divalent rare earth ions and photochromic effect

    Egranov, A. V.; Sizova, T. Yu.; Shendrik, R. Yu.; Smirnova, N. A.


    It was shown that the divalent rare earth ions (La, Ce, Gd, Tb, Lu, and Y) in cubic sites in alkaline earth fluorides are unstable with respect to electron autodetachment since its d1(eg) ground state is located in the conduction band which is consistent with the general tendency of these ions in various compounds. The localization of doubly degenerate d1(eg) level in the conduction band creates a configuration instability around the divalent rare earth ion that leading to the formation of an...

  19. Microwave studies on double rare earth oxalate crystals

    Elizabeth, Anit [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Joseph, Cyriac [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Paul, Issac [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Ittyachen, M.A. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Mathew, K.T. [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India)]. E-mail:; Lonappan, Anil [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India); Jacob, Joe [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India)


    Rare earth compounds are recognized for outstanding physical, magnetic and optical properties. The oxalates and molybdates have gained importance for their various properties, which find applications in electro and accusto optical devices. This paper reports the microwave dielectric studies on double rare earth oxalate crystals. Using the cavity perturbation technique dielectric parameters such as complex permittivity and conductivity at microwave frequencies is determined. Using X-ray diffraction study the crystalline nature of the samples was established. The molecular and crystal structures were identified by IR analysis.

  20. Improvement of magnetocaloric properties of Gd-Ge-Si alloys by alloying with iron

    Erenc-Sędziak T.


    Full Text Available The influence of annealing of Gd5Ge2Si2Fex alloys at 1200°C and of alloying with various amount of iron on structure as well as thermal and magnetocaloric properties is investigated. It was found that annealing for 1 to 10 hours improves the entropy change, but reduces the temperature of maximum magnetocaloric effect by up to 50 K. Prolonged annealing of the Gd5Ge2Si2 alloy results in the decrease of entropy change due to the reduction of Gd5Ge2Si2 phase content. Addition of iron to the ternary alloy enhances the magnetocaloric effect, if x = 0.4 – 0.6, especially if alloying is combined with annealing at 1200°C: the peak value of the isothermal entropy change from 0 to 2 T increases from 3.5 to 11 J/kgK. Simultaneously, the temperature of maximum magnetocaloric effect drops to 250 K. The changes in magnetocaloric properties are related to the change in phase transformation from the second order for arc molten ternary alloy to first order in the case of annealed and/or alloyed with iron. The results of this study indicate that the minor addition of iron and heat treatment to Gd-Ge-Si alloys may be useful in improving the materials’ magnetocaloric properties..

  1. Cast iron-base alloy for cylinder/regenerator housing

    Witter, Stewart L.; Simmons, Harold E.; Woulds, Michael J.


    NASACC-1 is a castable iron-base alloy designed to replace the costly and strategic cobalt-base X-40 alloy used in the automotive Stirling engine cylinder/generator housing. Over 40 alloy compositions were evaluated using investment cast test bars for stress-rupture testing. Also, hydrogen compatibility and oxygen corrosion resistance tests were used to determine the optimal alloy. NASACC-1 alloy was characterized using elevated and room temperature tensile, creep-rupture, low cycle fatigue, heat capacity, specific heat, and thermal expansion testing. Furthermore, phase analysis was performed on samples with several heat treated conditions. The properties are very encouraging. NASACC-1 alloy shows stress-rupture and low cycle fatigue properties equivalent to X-40. The oxidation resistance surpassed the program goal while maintaining acceptable resistance to hydrogen exposure. The welding, brazing, and casting characteristics are excellent. Finally, the cost of NASACC-1 is significantly lower than that of X-40.

  2. Evolution of Mg-5Al-0.4Mn microstructure after rare earth elements addition

    A. Żydek


    Full Text Available Mg-5Al-0.4Mn-xRE (x = 0, 1, 2, 3 wt.% magnesium alloys were prepared successfully by casting method. The microstructure wasinvestigated by light microscopy. The influence of rare earth (RE elements on the area fraction of eutectic was analysed. The obtainedresults revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. However, whilerare earth elements were added to the Mg-Al type alloy, Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitatesincreased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased.

  3. Constitution and magnetism of iron and its alloys

    Pepperhoff, Werner


    Iron played an important role in the development of the industrial society and has not lost any of its significance since today. This book provides the foundations of understanding the physical nature of iron and its alloys. Basics and recent developments concerning its constitution and magnetism are presented as well as its thermal properties. The exceptional role of iron with its wide spectrum of most different technological and physical properties relies on its versatility, its polymorphism of its crystal structure and its magnetism. Therefore it is the aim of the book to link together the constitution and magnetism of iron.

  4. A TEM Study on the Ti-Alloyed Grey Iron

    Moumeni, Elham; Tiedje, Niels Skat; Grumsen, Flemming Bjerg;


    The microstructure of graphite flakes in titanium alloyed cast iron is studied using electron microscopy techniques. Dual beam SEM/FIB has been used for TEM sample preparation. A TEM study has been carried out on graphite flakes in grey cast iron using selected area electron diffraction. Based...... on the selected area diffraction pattern analysis, crystallographic orientations are identified and compared. The orientation relationship between iron and graphite crystals at the interface is studied and discussed. It is found that graphite in the Ti-containing iron is extremely fine grained...

  5. Liquid-liquid extraction and separation of total rare earth (RE) metals from polymetallic manganese nodule leaching solution

    PK Parhi; KH Park; CW Nam; JT Park


    The study on the solvent extraction for quantitative and selective separation of total rare earth metals from the polymetallic nodule leach liquor was investigated. The typical leach liquor bearing 0. 094 g/L total rare earth, 0. 23 g/L Mn, 0.697 g/L Cu, 0.2 g/L Fe, 0.01 g/L Co and 0.735 g/L Ni was subjected to the removal iron content by precipitation method using Ca(OH)2 at pH 3.95, prior to solvent extraction of rare earth metals. Three different organo-phosphoric acid reagents (D2EHPA, PC88A, Cyanex 272) were used to ascertain their performances and selectivity towards the loading of rare earth metals in presence of other base metals. Based on the results of eq. pH effect, the performances of above three extractants followed the order as:D2EHPA>PC88A>Cyanex 272. To ensure the absence of extraction of base metals (Cu, Co, Ni), the eq. pH of the solution was optimized at the level of 2.21, though higher rare earth metal extraction efficiency was observed at higher eq. pH with either of the extractants. The complete process flow diagram for substantial recovery of total rare earth was developed using D2EHPA. Extraction isotherm plot was constructed at A:O=12:1, 3-stages and pHe=2.21, using 0.8 mol/L D2EHPA and the predicted condition of this study was further confirmed by 6-Cycles Counter Current Simulation (CCS) study. The stripping of total rare earth from loaded organic phase (LO) was conducted using HCl solution. Mc-Cabe Thiele diagram study carried out at A:O=1:5 using 4 mol/L HCl showed that three theoretical stages were needed for quantitative stripping of total rare earth. The subsequent stripped solution resulted thus led to contain total rare earth of 5.6 g/L indicating a very high enrichment of total metals by solvent extraction (SX) process.

  6. Rare earths & climate change,new energy,energy conservation and pollution reduction(continued)


    @@ Ⅲ.Contribution of rare earths to energy conservation Rechargeable batteries and rare earth permanent magnetic motor matching with batteries in every Prius car consume approximately 10 kg of rare-earth hydro-gen storage materials and 2 kg of rare earth permanent magnetic materials respectively.

  7. Trace Level Rare Earth Elements Separation From Gram Scale Uranium by Calcium Fluoride Coprecipitation

    WANG; Xiu-feng


    In the fission yield measurement of rare earth elements of uranium induced by neutron,and the analysis of rare earth elements in spent fuel,the separation of trace rare earth elements from a large number of uranium has very important significance.We separated trace level rare earth elements from gram scale uranium by calcium fluoride coprecipitation in this paper.

  8. Study on Al-Cu-Si braze containing small amount of rare earth erbium

    Yao-wu SHI; Yang YU; Zhi-dong XIA; Yong-ping LEI; Xiao-yan LI; Fu GUO; Jian-ping LIU


    In the present work, the effect of a small amount of rare earth Er addition on the microstructure of Al-Cu-Si brazing alloy has been investigated. In the study, the Al-20Cu-7Si brazing alloys with various Er contents were prepared. 3003 aluminum alloy was chosen as a substrate The microstructure of the brazed alloys was carefully observed. In addition, melting temperature, wettability and hardness of the brazing alloys were mea-sured. The results indicate that the constituent of the microstructure of Al-20Cu-7Si-Er brazed alloy is similar to the Al-20Cu-7Si, which is mainly comprised of solid solutions of aluminum, silicon and the intermetallic com-pounds CuAl2. When the Er content increases, the size of AI phases is decreased, and the filament-like or needle-like Si phase is thickened. The Si phases dominating in the shape of a filament or needle are transformed to those in the shape of a block when Er content is increased. Moreover, adding a small amount of Er can improve the wettability and hardness of the Al-20Cu-7Si brazing alloy. However, the melting temperature of the Al-20Cu-7Si alloy is almost unchanged when a small amount of Er is added.

  9. Low-aluminum content iron-aluminum alloys

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J. [and others


    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10 and iron = 83.71. The ignots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot-worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  10. Geochemical Characteristics and Behaviors of Rare Earth Elements in Process of Vertisol Development

    黄成敏; 王成善


    Vertisol developed on argillaceous rocks has its special pedogenic processes and properties, and formed some secondary nodules. In study area, contents of rare earth elements (REE) are significantly different in different sedimentary rocks due to varied contents of clay fraction and clay mineral composition, etc. Under the dry and hot climate, REEs were less differentiated than their parent sedimentary rocks. However, REEs in secondary nodules formed in pedogenic process display their specific behaviors. They are more concentrated in iron concretions, the content of heavy REEs increases relatively, and positive Ce-anomaly appeares. But, negative Ce-anomaly was found in calcium concretions, while normal Ce content in parent rocks and vertisol.

  11. Extraction of rare earth elements from hydrate-phosphate precipitates of apatite processing

    Andropov, M. O.; Anufrieva, A. V.; Buynovskiy, A. S.; Makaseev, Y. N.; Mazov, I. N.; Nefedov, R. A.; Sachkov, V. I.; Stepanova, O. B.; Valkov, AV


    The features of extraction of rare earth elements (REE) were considered from hydrate-phosphate precipitates of REE of apatite processing by nitric acid technology. The preliminary purification of nitrate solution of REE from impurities of titanium, aluminum, iron, uranium and thorium was suggested to obtain stable solutions not forming precipitates. Washing the extract was recommended with the evaporated reextract that allows to obtain directly on the cascade of REE extraction the concentrated solutions suitable for the separation into groups by the extraction method. Technical decisions were suggested for the separation of REE in groups without the use of salting-out agent.

  12. Processing and Protection of Rare Earth Permanent Magnet Particulate for Bonded Magnet Applications

    Sokolowski, Peter Kelly [Iowa State Univ., Ames, IA (United States)


    Rapid solidification of novel mixed rare earth-iron-boron, MRE2Fe14B (MRE = Nd, Y, Dy; currently), magnet alloys via high pressure gas atomization (HPGA) have produced similar properties and structures as closely related alloys produced by melt spinning (MS) at low wheel speeds. Recent additions of titanium carbide and zirconium to the permanent magnet (PM) alloy design in HPGA powder (using He atomization gas) have made it possible to achieve highly refined microstructures with magnetic properties approaching melt spun particulate at cooling rates of 105-106K/s. By producing HPGA powders with the desirable qualities of melt spun ribbon, the need for crushing ribbon was eliminated in bonded magnet fabrication. The spherical geometry of HPGA powders is more ideal for processing of bonded permanent magnets since higher loading fractions can be obtained during compression and injection molding. This increased volume loading of spherical PM powder can be predicted to yield a higher maximum energy product (BH)max for bonded magnets in high performance applications. Passivation of RE-containing powder is warranted for the large-scale manufacturing of bonded magnets in applications with increased temperature and exposure to humidity. Irreversible magnetic losses due to oxidation and corrosion of particulates is a known drawback of RE-Fe-B based alloys during further processing, e.g. injection molding, as well as during use as a bonded magnet. To counteract these effects, a modified gas atomization chamber allowed for a novel approach to in situ passivation of solidified particle surfaces through injection of a reactive gas, nitrogen trifluoride (NF3). The ability to control surface chemistry during atomization processing of fine spherical RE-Fe-B powders produced advantages over current processing methodologies. In particular, the capability to coat particles while 'in flight' may eliminate the

  13. Automation System in Rare Earths Countercurrent Extraction Processes

    贾江涛; 严纯华; 廖春生; 吴声; 王明文; 李标国


    Based on the countercurrent extraction theory for optimized designing and simulating, the rare earth separation processes, the selection of the detecting points (stages) and on-line analysis for elements, the simulation of open loop response and its response speed, the diagnosis and the regulative prescription for running the solvent extraction cascades were studied.

  14. Direct Reuse of Rare Earth Permanent Magnets—Coating Integrity

    Høgberg, Stig; Holbøll, Joachim; Mijatovic, Nenad


    Rare earth permanent magnets can be reused directly as an alternative to traditional recycling methods, in which scrapped magnets are reprocessed into new magnets by undergoing many of the original energy-intensive and expensive production processes. Direct reuse entails using segmented magnet...

  15. Systematic hardness measurements on some rare earth garnet crystals

    D B Sirdeshmukh; L Sirdeshmukh; K G Subhadra; K Kishan Rao; S Bal Laxman


    Microhardness measurements were undertaken on twelve rare earth garnet crystals. In yttrium aluminium garnet and gadolinium gallium garnet, there was no measurable difference in the hardness values of pure and nominally Nd-doped crystals. The hardness values were correlated with the lattice and elastic constants. An analysis of hardness data in terms of the interatomic binding indicated a high degree of covalency.

  16. Instability of some divalent rare earth ions and photochromic effect

    Egranov, A. V.; Sizova, T. Yu.; Shendrik, R. Yu.; Smirnova, N. A.


    It was shown that the divalent rare earth ions (La, Ce, Gd, Tb, Lu, and Y) in cubic sites in alkaline earth fluorides are unstable with respect to electron autodetachment since its d1(eg) ground state is located in the conduction band which is consistent with the general tendency of these ions in various compounds. The localization of doubly degenerate d1(eg) level in the conduction band creates a configuration instability around the divalent rare earth ion that leading to the formation of anion vacancy in the nearest neighborhood, as was reported in the previous paper [A. Egranov, T. Sizova, Configurational instability at the excited impurity ions in alkaline earth fluorites, J. Phys. Chem. Solids 74 (2013) 530-534]. Thus, the formation of the stable divalent ions as La, Ce, Gd, Tb, Lu, and Y (PC+ centers) in CaF2 and SrF2 crystals during x-ray irradiation occurs via the formation of charged anion vacancies near divalent ions (Re2+va), which lower the ground state of the divalent ion relative to the conductivity band. Photochromic effect occurs under thermally or optically stimulated electron transition from the divalent rare earth ion to the neighboring anion vacancy and reverse under ultraviolet light irradiation. It is shown that the optical absorption of the PC+ centers due to d → d and d → f transitions of the divalent rare-earth ion.

  17. Primary Results of New Rare Earth Materials for Hongti Grape

    He Qiong; Gu Jiangyuan; Wang Jiachen


    New rare earth (RE) materials including RE phosphate as base fertilizer, bioactive RE micro-fertilizer and RE entire plant nutrition agent as topdressing fertilizer are treated on Hongti grope.The result showes that the plant leaves become thicker, the color is dark green, the plant disease index is lower, and the sugar content significantly increases.

  18. Strategy of Development of Rare Earth Industry in China

    Su Wenqing


    This work introduced the current situation of the development of domestic and foreign rare earths (RE) industry, discussed the strategic position of RE industry in China, analyzed the problems existing in the course of RE industry development, made strategic thought about the transference from resource advantage to economic advantage, and put forward strategic suggestions about the development of RE industry in our country.

  19. Rare earth point defects in GaN

    Sanna, S.


    In this work we investigate rare earth doped GaN, by means of theoretical simulations. The huge unit cells necessary to model the experimental system, where dilute amount of rare earth ions are used, are handled with the charge self consistent density-functional based-tight binding (SCC-DFTB) calculational scheme. The method has been extended to include LDA+U and simplified self interaction corrected (SIC)-like potentials for the simulation of systems with localised and strongly correlated electrons. A set of tight-binding parameters has been created to model the interaction of GaN with some dopants, including a selection of lanthanide ions interesting due to their optical or magnetic properties (Pr, Eu, Gd, Er and Tm). The f-electrons were treated as valence electrons. A qualitatively correct description of the band gap is crucial for the simulation of rare earth doped GaN, because the luminescence intensity of the implanted samples depends on the size of the host band gap and because the rare earths could introduce charge transition levels near the conduction band. In this work these levels are calculated with the Slater-Janak (SJ) transition state model, which allows an approximate calculation of the charge transition levels by analysing the Kohn-Sham eigenvalues of the DFT. (orig.)

  20. Uncovering the end uses of the rare earth elements

    Du, Xiaoyue, E-mail: [Swiss Federal Laboratories for Materials Science and Technology (EMPA), Lerchenfeldstrasse 5, 9014 St. Gallen (Switzerland); Yale University, 195 Prospect Street, New Haven CT 06511 (United States); Graedel, T.E. [Yale University, 195 Prospect Street, New Haven CT 06511 (United States)


    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging and conventional established technologies. However, quantitative knowledge of REE remains sparse, despite the current heightened interest in future availability of the resources. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supply vulnerable to short term disruption. We have drawn upon the published literature and unpublished materials in different languages to derive the first quantitative annual domestic production by end use of individual rare earth elements from 1995 to 2007. The information is illustrated in Sankey diagrams for the years 1995 and 2007. Other years are available in the supporting information. Comparing 1995 and 2007, the production of the rare earth elements in China, Japan, and the US changed dramatically in quantities and structure. The information can provide a solid foundation for industries, academic institutions and governments to make decisions and develop strategies. - Highlights: • We have derived the first quantitative end use information of the rare earths (REE). • The results are for individual REE from 1995 to 2007. • The end uses of REE in China, Japan, and the US changed dramatically in quantities and structure. • This information can provide solid foundation for decision and strategy making.

  1. Dissolved rare earth elements in the Black Sea

    Schijf, Johan; Baar, Hein J.W. de; Wijbrans, Jan R.; Landing, William M.


    Concentrations of rare earths in the deep anoxic Black Sea are about one order of magnitude higher than in normal open ocean waters. From a minimum at the suboxic-anoxic interface at about 107 m depth, concentrations increase strongly to a maximum at about 300–400 m depth. Concentrations of Ce range

  2. An introduction to the economics of rare earths

    Bartekova, E.


    The aim of this paper is to examine the supply risk of rare earths and its impact on low carbon technologies deployment. Bringing together seemingly disconnected strands of scientific literature, this multidisciplinary approach allows to provide an overarching overview of the economics of rare

  3. XU Guangxian: Father of Chinese rare earths chemistry

    XIN Ling


    @@ Decades ago, he invented a cascade extraction theory and technique that have greatly facilitated the production of the so-called "industrial vitamins," shifting China's role from a low-profit exporter of raw ores to the world's dominant supplier of separated individual rare earth compounds and metals in high purity.

  4. Electrons and Spin Waves in Heavy Rare Earth Metals

    Mackintosh, A. R.


    Although the main principles governing the magnetic interactions and magnetic ordering in rare earth metals have been qualitatively understood for some time, it is only relatively recently that a sufficiently detailed study has been made of their electronic and magnetic excitations to place this ...

  5. Complex Electronic Structure of Rare Earth Activators in Scintillators

    Aberg, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Yu, S. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zhou, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    To aid and further the understanding of the microscopic mechanisms behind the scintillator nonproportionality that leads to degradation of the attainable energy resolution, we have developed theoretical and experimental algorithms and procedures to determine the position of the 4f energy levels of rare earth dopants relative to the host band edge states.

  6. Opinions on hot discussions in connection with rare earths recently (continued)


    @@ IV.Rare earths are mostly for civil uses Rare earth elements have excellent physical properties including optical, electric, magnetic, superconductive and catalytic performances and outstanding .chemical properties.The value of rare earths is mostly embodied in their applications.Rare earths are prepared into various advanced materials with different performances.Therefore, rare earths enjoy the reputation of "industrial monosodium glutamate" and "treasury of advanced materials".

  7. The Silumin Coat Structure on Alloy Ductile Iron

    Szymczak T.


    Full Text Available The work presents the research results of the silumin coat structure applied on the carbidic alloy ductile iron with the metal matrix: pearlitic, bainitic and martensitic. The coats were made in the AlSi5 silumin bath at the temperature tk = 750±5°C. The holding time of cast iron element in the bath was τ = 180s. Irrespective of the kind of tested ductile iron the obtained coat consisted of three layers with a different phase composition. The first layer from the cast iron ground “g1`” is built from Fe4CSi carbide which contains selected alloy additives of the cast iron. On it the second layer “g1``” crystallizes. It consists of the AlFeSi inter-metallic phase which can appear in its pure form or contain a small quantity of the alloy additives of the cast iron. The last external part of the layer “g2” mainly consists of the hypo-eutectic phases of silumin. The AlFeSi inter-metallic phases in the form of free precipitations with a lamellar or faceted morphology can also appear there. These phases also can contain a small quantity of the alloy additives of the cast iron. More than that, in all the layers of the coat there are graphite precipitations. The phenomenon of graphite movement to the coat is caused by intensive dissolving of the cast iron element surface by the aluminum of the silumin bath.

  8. A review of magnetostrictive iron-gallium alloys

    Atulasimha, Jayasimha; Flatau, Alison B.


    A unique combination of low hysteresis, moderate magnetostriction at low magnetic fields, good tensile strength, machinability and recent progress in commercially viable methods of processing iron-gallium alloys make them well poised for actuator and sensing applications. This review starts with a brief historical note on the early developments of magnetostrictive materials and moves to the recent work on FeGa alloys and their useful properties. This is followed by sections addressing the challenges specific to the characterization and processing of FeGa alloys and the state of the art in modeling their actuation and sensing behavior.

  9. Carbide Transformations in Tempering of Complexly Alloyed White Cast Iron

    Vdovin, K. N.; Gorlenko, D. A.; Zavalishchin, A. N.


    Variation of the chemical composition of all phases and structural components (metallic matrix, eutectic and secondary carbides) in complexly alloyed cast iron is studied after crystallization and different variants of tempering. It is shown that several groups of secondary carbides may be distinguished according to their morphology and chemical composition.

  10. Oxidation resistant iron and nickel alloys for high temperature use

    Hill, V. L.; Misra, S. K.; Wheaton, H. L.


    Iron-base and nickel-base alloys exhibit good oxidation resistance and improved ductility with addition of small amounts of yttrium, tantalum /or hafnium/, and thorium. They can be used in applications above the operating temperatures of the superalloys, if high strength materials are not required.

  11. Textural and morphological studies on zinc-iron alloy electrodeposits

    M Kanagasabapathy; Sobha Jayakrishnan


    Zinc-iron alloy electrodeposits have industrial significance, since they provide better corrosion resistance and with improved mechanical properties when compared to pure zinc coatings. This is due to the unique phase structure of the alloy formed. But this deposition belongs to anomalous deposition, where the electrochemically less noble zinc deposits more preferentially, than the more noble iron. So the industrial process control over the deposition becomes difficult. So, this study correlates the effect of various deposition parameters over the deposition kinetics and deposited alloy characteristics. Transition and partial current densities were computed. Effect of hydrogen overpotential and surface coverage due to the adsorbed intermediates over anomalous deposition were explored. Plausible deposition mechanism and mathematical model was proposed to predict the anomalous electrodeposition characteristics. Textural, morphological and phase structural characteristics of the alloy was investigated. By the substitution of iron in the hcp lattice, c/a ratio was lowered and the lattice geometry was distorted. Intermetallic compounds of variable composition such as FeZn14, Fe5Zn33, Fe3Zn13 and FeZn3 with `' and `' phase structures were noted. Electrodeposition parameters were optimized and smooth, adherent, strain-free deposits with required iron content and hardness were obtained.

  12. Influence of selected rare earth metals on structural characteristics of 42CrMo4 steel

    J. Drápala


    Full Text Available The influence of rare earth metals (REM addition on solidification structure of the low-carbon 42CrMo4 steel was investigated. Alloys were prepared by means of a centrifugal casting. The addition of cerium, praseodymium or mischmetal in the steel produced greatly improved solidification structure with a suppressed columnar grain zone, finer grain size in the equiaxed grain zone. The additions occurred in the steel bath in the form of REM oxide and/or oxide-sulphide inclusions and as dissolved REM segregated along with other elements at prior grain boundaries and interdendritic spaces. Microstructure (light microscope, SEM/EDX chemical microanalysis, and TOF-SIMS analysis – mapping of elements in the structure of alloys were obtained.

  13. The occurrence of rare earth elements in some Finnish mires

    Yliruokanen, I.


    Full Text Available The content of the more abundant rare earths (RE (Y, La, Ce, Pr, Nd and Sm in the ash of 399 peat samples from 26 Finnish mires was determined by X-ray fluorescence spectrometry. The content of all rare earths (La-Lu, Y in 29 samples was also determined by spark source mass spectrometry. The median RE contents in peat ashes from areas where the bedrock consists of rapakivi granite, granite or archean gneiss are reported. Detailed data concerning the individual mires are also presented. The highest RE contents were found in samples from rapakivi granite areas where a strong negative Eu anomaly was also observed. The RE contents were in general highest at the basal peat layers.

  14. Electronic and vibrational spectra of some rare earth trifluoromethanesulfonates crystals

    Paul, P.; Ghosh, M.; Neogy, D.; Mallick, P. K.


    The Raman and infrared spectra of some rare earth (dysprosium and terbium) trifluoromethanesulfonates crystals have been analyzed. Different vibrational frequencies of trifluoromethanesulfonate ions (CF 3SO 3-) are identified and assigned to different vibrations of the SO 3 and CF 3 groups. Electronic transitions of R 3+ ions (R = Dy, Tb) in these salts have been assigned to transitions from the ground to different energy levels of the ground multiplet. The electronic energy levels of the rare earth ions are also determined theoretically with the help of single electron crystal field theory. They are found to yield results not only in good agreement with the observed spectral data but also in good conformity with those obtained previously from magnetic measurements.

  15. Ionoluminescence of trivalent rare-earth-doped strontium barium niobate

    Calvo del Castillo, H. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain); Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Ruvalcaba, J.L. [Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Bettinelli, M.; Speghini, A. [Dipartimento Scientifico e Tecnologico, Universita di Verona and INSTM, UdR Verona, Ca Vignal, Strada Le Grazie 15, I-37134 Verona (Italy); Barboza Flores, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Hermosillo, Sonora (Mexico); Calderon, T. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain)], E-mail:; Jaque, D.; Garcia Sole, J. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)


    Ionoluminescence spectra for different rare-earth ion (Pr{sup 3+} and Eu{sup 3+})-activated Sr{sub x}Ba{sub 1-x}Nb{sub 2}O{sub 6} strontium barium niobate crystals (x=0.33 and 0.60) have been induced with a 3 MeV proton beam for a variety of beam current intensities (45, 40 and 20 nA). The proton-beam induced luminescent spectra have shown features associated with the presence of the rare-earth ion and some spectral features mostly related to the host crystal, which appear only for high beam current intensities. We have compared the ionoluminescence results to those obtained under UV light excitation (photoluminescence technique) where a direct excitation of the band gap would occur.

  16. Magnetomigration of rare-earth ions in inhomogeneous magnetic fields.

    Franczak, Agnieszka; Binnemans, Koen; Jan Fransaer


    The effects of external inhomogenous (gradient) magnetic fields on the movement of the rare-earth ions: Dy(3+), Gd(3+) and Y(3+), in initially homogeneous aqueous solutions have been investigated. Differences in the migration of rare-earth ions in gradient magnetic fields were observed, depending on the magnetic character of the ions: paramagnetic ions of Dy(3+) and Gd(3+) move towards regions of the sample where the magnetic field gradient is the strongest, while diamagnetic ions of Y(3+) move in the opposite direction. It has been showed that the low magnetic field gradients, such the ones generated by permanent magnets, are sufficient to observe the magnetomigration effects of the ions in solution. The present work clearly establishes the behavior of magnetically different ions in initially homogeneous aqueous solutions exposed to magnetic field gradients. To this avail, a methodology for measuring the local concentration differences of metal ions in liquid samples was developed.

  17. Thermochemistry of Rare Earth Silicates for Environmental Barrier Coatings

    Costa, Gustavo; Jacobson, Nathan


    Rare earth silicates are promising candidates as environmental protective coatings (EBCs) for silica-forming ceramics and composites in combustion environments since they are predicted to have lower reactivity with the water vapor combustion products. The reactivity of rare earth silicates is assessed by the thermodynamic activity of the silica component which is best measured by Knudsen effusion mass spectrometry (KEMS). Here, we discuss a novel method based on a reducing agent to increase the partial pressure of SiO(g) which is then used to calculate thermodynamic activity of silica in Y2O3-SiO2 and Yb2O3-SiO2 systems. After the KEMS measurements, samples were probed by X-ray diffraction and their phase content was calculated from Rietveld refinement.

  18. Research of Optical Performance On Rare-Earth Optical Fiber

    Li Baojun; Zhou Meng; Yang Tao; Zhou Yao; Fu Li; Li Tiansi; YangShilong


    The rare-earth optical fiber is made of organic material and inorganic rare earth material.It can be used to absorb and transfer solar energy.When sunlight irradiates, it may absorb and transfer solar energy automatically; while at night or without sunlight it may give out light and play role of decoration.By utilizing high transmissivity of organic material and heat-resisting performance of inorganic material, we know the reorganization of material performance under the melting condition, and make empty core bear the high temperature of 150 ~200 ℃.When the light spreads in light guide, some light energy travels along the direction of light guide, and is introduced in the room directly.Another part of light energy is absorbed and stored by light guide, and can release light again after 8 ~ 12 h.

  19. Calcination-Digestion-Desliming of Phosphorus Ore Bearing Rare Earth

    Zhang Qin; Zhang Jie; Wang Jing; Qiu Yue qin


    The recoveries of phosphorus and RE of ore from Zhijin in Guizhou were studied.The influences of the calcination temperature, resident time, the digested time and water volume of the calcinating on concentrate yield by desliming were also investigated by orthogonal design.Appropriate calcination temperature is initial condition that makes carbonate mineral decomposition.The recovery of phosphorus is 83.02% and rare earth is 90.56% in phosphorus concentrate when calcined temperature is 900 ℃, other conditions include: calcined time is 30 min, digestion water volume is 300 ml, digestion time is 20 min.The results show that the pre-treatment of the ore is favorable for the separation and enrichment of rare earth from phosphorus ore, and a process of calcination-digestion-desliming was promised.

  20. Review of Studies on Rare Earth against Plant Disease

    慕康国; 张文吉; 崔建宇; 张福锁; 胡林


    Agricultural application of rare earth (RE) has been generalized for several decades, and it is involved in crops, vegetables and stock raising in China. However, all the researches on RE mainly focus on the fields such as plant physiological activity, physiological and biochemical mechanism, sanitation toxicology and environmental security. Plant protection by using RE and the induced resistance of plant against diseases were summarized. The mechanism of rare earth against plant disease is highlighted, which includes following two aspects. First, RE elements can control some phytopathogen directly and reduce its virulence to host plant. Another possibility is that RE elements can affect host plant and induce the plant to produce some resistance to disease.

  1. Observation of anomalous phonons in orthorhombic rare-earth manganites

    Gao, P.; Chen, H. Y.; Tyson, T. A.; Liu, Z. X.; Bai, J. M.; Wang, L. P.; Choi, Y. J.; Cheong, S.-W.


    We observe the appearance of a phonon near the lock-in temperature in orthorhombic REMnO3 (RE denotes rare earth) (RE: Lu and Ho) and anomalous phonon hardening in orthorhombic LuMnO3. The anomalous phonon occurs at the onset of spontaneous polarization. No such changes were found in incommensurate orthorhombic DyMnO3. These observations directly reveal different electric polarization mechanisms in the E-type and incommensurate-type orthorhombic REMnO3.


    JIN Yingtai; ZHANG Xitian; PEI Fengkui; WU Yue


    The reaction mechanisms ofdiene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of 1H- NM R, one- and two- dimensions 13C-NMR. Based on the data of above NMR spectra, it is proposed that the polymerization reaction proceeds according to the following mechanism: η4-diene (cis- (→)trans- )and η3-allyl (syn- (→)anti- ).

  3. Advances in Rare Earth Application to Semiconductor Materials and Devices



    The development of rare earths (RE) applications to semiconductor materials and devices is reviewed. The recent advances in RE doped silicon light emitting diodes (LED) and display materials are described. The various technologies of incorporating RE into semiconductor materials and devices are presented. The RE high dielectric materials, RE silicides and the phase transition of RE materials are also discussed. Finally, the paper describes the prospects of the RE application to semiconductor industry.

  4. Coherent optical ultrasound detection with rare-earth ion dopants

    Tay, Jian Wei; Longdell, Jevon


    We describe theoretical and experimental demonstration for optical detection of ultrasound using a spectral hole engraved in cryogenically cooled rare-earth ion doped solids. Our method utilizes the dispersion effects due to the spectral hole to perform phase to amplitude modulation conversion. Like previous approaches using spectral holes it has the advantage of detection with large \\'etendue. The method also has the benefit that high sensitivity can be obtained with moderate absorption contrast for the spectral holes.

  5. High photoluminescence efficiency in polymer containing rare earth

    Zhefu Wu; Qidan Ling; Xugang Shi; Jiangxin Zhang; Guangxin Zhu


    @@ Three novel kinds of polymers containing rare earth europium have been synthesized and the integrating sphere technique was employed to measure the absolute photoluminescence (PL) efficiency. The PL efficiencies were found to be up to about 40%, which indicates the potential usage in organic light emitting devices (OLED). The energy transfer from ligand to Eu ions and the 5D0 → 7F2 transition of Eu3+ were analyzed under the PL process.

  6. Rare-earth ions doped transparent oxyfluoride glass-ceramics


    In recent years, rare-earth ions doped transparent oxyfluoride glass-ceramics have attracted great attentions for their low phonon energy environments of fluoride nanocrystals and high chemical and mechanical stabilities of oxide glassy matrix. In this chapter, firstly, the crystallization behaviors of the transparent glassceramics containing CaF2 nanocrystals are presented to demonstrate the controllable microstructure evolution of nano-composites. Secondly, the optical properties of the new...

  7. Growth of oriented rare-earth-transition-metal thin films

    Fullerton, E.E.; Sowers, C.H.; Bader, S.D. [Argonne National Lab., IL (United States); Wu, X.Z. [Argonne National Lab., IL (United States)]|[Northern Illinois Univ., DeKalb, IL (United States)


    Rare-earth-transition-metal thin films are successfully grown by magnetron sputtering onto single-crystal MgO substrates with epitaxial W buffer layers. The use of epitaxial W buffer layers allows oriented single-phase films to be grown. Sm-Co films grown onto W(100), have strong in-plane anisotropy and coercivities exceeding 5 T at 5 K whereas Fe-Sm films have strong perpendicular anisotropy and are magnetically soft.

  8. Experimental Temperature and Heat Capacity in Rare Earth Nuclei

    Melby, E.; Bergholt, L.; Guttormsen, M.; Hjorth-Jensen, M.; Ingebretsen, F.; Messelt, S.; Rekstad, J.; Schiller, A.; Siem, S.; Ødegård, S. W.

    Temperature and heat capacity for the rare earth nuclei 162Dy, 166Er and 172Yb have been extracted from experimental data at the Oslo Cyclotron Laboratory (OCL). The starting point to determine thermodynamical quantities is the density of levels as a function of excitation energy. The density of accessible levels in the (3He,α γ)-reaction has been extracted from measured γ-spectra.

  9. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    Timothy A. DeVol; Basak Yazgan-Kukouz; Baris Kokuoz; DiMaio, Jeffrey R.; Kevin B. Sprinkle; Tiffany L. James; Courtney J. Kucera; JACOBSOHN, Luiz G.; John Ballato


    This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE) doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP) that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminesc...

  10. Processing of Phosphorus Slag with Recovery of Rare Earth Metals and Obtaining Silicon Containing Cake

    Karshigina, Zaure; Abisheva, Zinesh; Bochevskaya, Yelena; Akcil, Ata; Sharipova, Aynash; Sargelova, Elmira


    The present research is devoted to the processing of slag generating during the yellow phosphorus production. In this paper are presented studies on leaching of phosphorus production slag by nitric acid with recovery of rare earth metals (REMs) into solution. REMs recovery into the solution achieved 98 % during the leaching process with using 7.5 mol/L of HNO3, liquid-to-solid ratio is 2.6:1, temperature is 60°C, process duration is 1 hour and stirrer speed is 500 rpm. Behaviour during the leaching of associated components such as calcium, aluminium, and iron was studied. After the leaching cake contains ∼⃒75-85 % of SiO2 and it might be useful for obtaining of precipitated silicon dioxide. With the purpose of separation from the impurities, recovery and concentrating of REMs, the obtained solution after leaching was subjected to extraction processing methods. The influence of ratio of organic and aqueous phases (O: A) on the extraction of rare earth metals by tributyl phosphate (TBP) with concentrations from 20 up to 100 % was studied. The REMs extraction with increasing TBP concentration under changes O:A ratio from 1:20 down to 1:1 into the organic phase from the solutions after nitric acid leaching increased from 22.2 up to 99.3%. The duration effect of REMs extraction process was studied by tributyl phosphate. It is revealed that with increasing of duration of the extraction process from 10 to 30 minutes REMs recovery into the organic phase almost did not changed. The behaviour of iron in the extraction process by TBP was studied. It was found that such accompanying components as calcium and aluminium by tributyl phosphate didn't extracted. To construct isotherm of REMs extraction of by tributyl phosphate was used variable volume method. It was calculated three-step extraction is needed for REMs recovery from the solutions after nitric acid leaching of phosphorus production slag. The process of the three-steps counter current extraction of rare earth

  11. Existing State and Partitioning of Rare Earth on Weathered Ores


    The existing state and partitioning of rare earth (RE) on weathered ores in Longnan County (LN), Xingfeng County(XF) and Ninghua County(NH) were characterized systematically by standard geological analytical methods. It is found that RE in the weathered rare earth ores exist as four phases: (a) water soluble, (b) ion-exchangeable, (c) colloidal sediment (oxides), (d) minerals, in which mainly as ion exchangeable phase, accounting for nearly 80% of total RE,with about 20% in the form of colloid sediment phase and mineral phase, but very little as aqueous soluble phase. These rare earth partitioning were mainly chosen mid-heavy RE elements, occupying above 60%, but not equal in the four phases. The mid-heavy RE elements were primarily enriched in the ion exchangeable phase up to 40%, while the containment of cerium dioxide is below 2%. The cerium deficiency occurs in the ion exchangeable phase in weathered ore. It results from that the Ce3+ is oxidized into Ce4+ and changes into CeO2. For LN ore, the containment of Y is high in weathered ore because Y-minerals are abundant in original rock.

  12. Preparation of mixed rare earths modified chitosan for fluoride adsorption

    梁鹏; 张艺; 汪东风; 徐莹; 罗斓


    This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan (CR). Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). La(III)-modified chitosan (CL) was also prepared as control. For the batch technique, the effects of various parameters such as contact time, pH, adsorbent dose, initial fluoride concentration and co-ions on fluoride adsorption were studied. Fourier trans-form infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize adsorbents. It was observed that the fluo-ride adsorption capacity of CR (3.72 mgF-/g) was higher than CL (3.16 mgF-/g) at 2 h. The presence of co-ions such as bicarbonate and carbonate greatly affected the fluoride adsorption from water. Characterization experiments indicated the successful chelation between mixed rare earths and chitosan. The possible fluoride adsorption mechanism of CR was explained by a chemical reaction.

  13. Recovery of rare earth metals through biosorption:An overview

    Nilanjana Das; Devlina Das


    Rare earth metals (REMs) are a series of 17 elements that have widespread and unique applications in high technology, power generation, communications, and defense industries. These resources are also pivotal to emergent sustainable energy and car-bon alternative technologies. Recovery of REMs is interesting due to its high market prices along with various industrial applications. Conventional technologies, viz. precipitation, filtration, liquid-liquid extraction, solid-liquid extraction, ion exchange, super critical extraction, electrowinning, electrorefining, electroslag refining, etc., which have been developed for the recovery of REMs, are not economically attractive. Biosorption represents a biotechnological innovation as well as a cost effective excellent tool for the recovery of rare earth metals from aqueous solutions. A variety of biomaterials such as algae, fungi, bacteria, resin, activated carbon, etc., have been reported to serve as potential adsorbents for the recovery of REMs. The metal binding mechanisms, as well as the parameters in-fluencing the uptake of rare earth metals and isotherm modeling are presented here. This article provides an overview of past achievements and current scenario of the biosorption studies carried out using some promising biosorbents which could serve as an economical means for recovering REMs. The experimental findings reported by different workers will provide insights into this re-search frontier.

  14. The valence and spectral properties of rare-earth clusters

    Peters, L; Litsarev, M S; Katsnelson, A Delin M I; Kirilyuk, A; Johansson, B; Sanyal, B; Eriksson, O


    The rare-earths are known to have intriguing changes of the valence, depending on chemical surrounding or geometry. Here we make predictions from theory that combines density functional theory with atomic multiplet-theory, on the transition of valence when transferring from the atomic divalent limit to the trivalent bulk, passing through different sized clusters, of selected rare-earths. We predict that Tm clusters show an abrupt change from pure divalent to pure trivalent at a size of 6 atoms, while Sm and Tb clusters are respectively pure divalent and trivalent up to 8 atoms. Larger Sm clusters are argued to likely make a transition to a mixed valent, or trivalent, configuration. The valence of all rare-earth clusters, as a function of size, is predicted from interpolation of our calculated results. We argue that the here predicted behavior is best analyzed by spectroscopic measurements, and provide theoretical spectra, based on dynamical mean field theory, in the Hubbard-I approximation, to ease experiment...

  15. Social and Environmental Impact of the Rare Earth Industries

    Saleem H. Ali


    Full Text Available The use of rare earth elements in various technologies continues to grow despite some alternatives being found for particular uses. Given a history of ecological concerns about pollution from rare earth mines, particularly in China, there are growing social and environmental concerns about the growth of the mining and mineral processing in this sector. This is best exemplified by the recent social and environmental conflict surrounding the development of the Lynas Advanced Materials Plant (LAMP in Kuantan, Malaysia which led to international activism and claims of environmental and social injustice. This paper analyses the structure of environmental and social conflicts surrounding rare earth minerals and opportunities for improving the social and environmental performance of the sector. Many of these elements are used for green technologies. Opportunities exist that offer a more circular supply chain following industrial ecological principles through which reuse and recycling of the materials can provide a means of mitigating social and environmental conflicts in this sector. In addition, public engagement processes that recognize community concerns about radiation, and transparent scientifically predicated decision-making through an appropriate governance structure within regulatory organizations are also presented.

  16. Rare Earths of Two Types Granites in Sawuer Region, Xinjiang

    Yuan Feng; Zhou Taofa; Tan Lugui; Fan Yu; Yue Shucang


    The geochemical characteristics of rare earth elements of A type and I type granites were studied in the Sawuer region, Xinjiang. The characteristics of two types granites are different obviously,because the A type and I type granites formed at different stage of the post-collisional period. The Sentasi intrusion and Wokensala intrusion are the I type granites formed at the late of post-collisional period, and there is extrusion translating to extension stress. The characteristics of rare earth elements show that the fractional crystallization of the I type granites is indistinct, and the sources of the I type granites come from the mantle. The Kuoyitasi intrusion and Qiaqihai intrusion are the A type granites formed at the end of post-collisional period, and there is extension stress. The characteristics of rare earth elements show that the fractional crystallization of the A type granites is distinct. The sources of the A type granites come from the mantle but interfused by the crust.

  17. Restoration of rare earth mine areas: organic amendments and phytoremediation.

    Zhou, Lingyan; Li, Zhaolong; Liu, Wen; Liu, Shenghong; Zhang, Limin; Zhong, Liyan; Luo, Ximei; Liang, Hong


    Overexploitation of rare earth mine has caused serious desertification and various environmental issues, and ecological restoration of a mining area is an important concern in China. In this study, experiments involving dry grass landfilling, chicken manure broadcasting, and plant cultivation were carried out to reclaim a rare earth mine area located in Heping County, Guangdong Province, China. The prime focus was to improve soil quality in terms of nutrients, microbial community, enzyme activity, and physicochemical properties so as to reclaim the land. After 2 years of restoration, an increase of organic matter (OM), available potassium (K), available phosphorus (P) levels, and acid phosphatase (ACP) activity and a reduction of the available nitrogen (N) level and urease (URE) activity in soil were achieved compared to the original mined land. The nutrients and enzyme activities in soil with 5 years of restoration were close to or surpass those in the unexploited land as control. The bulk density, total porosity, water holding capacity, pH, and electrical conductivity (EC) of soil were improved, and the number of cultivable microorganisms and the bacterial diversity in soil were greatly increased with time during ecological restoration, especially for surface soil. Furthermore, the artificial vegetation stably grew at the restored mining sites. The results indicated that organic amendments and phytoremediation could ecologically restore the rare earth mining sites and the mined land could finally be planted as farmland.

  18. Magnetization dynamics in rare earth doped NiFe films

    Kiessling, Matthias; Woltersdorf, Georg; Back, Christian [Institut fuer Experimentelle und Angewandte Physik, Universitaet Regensburg, D- 93040 Regensburg (Germany); Thiele, Jan-Ulrich; Schabes, Manfred [Hitachi Global Storage Technologies, 3403 Yerba Buena Road, San Jose, CA 95135 (United States)


    The influence of rare earth dopants on the damping parameter and the resulting possibility to control this parameter were investigated. In our experiments NiFe films were doped with Dysprosium, Holmium, Terbium, and Gadolinium. The magnetization dynamics of these rare earth doped films was mainly studied by means of ferromagnetic resonance (FMR) and network-analyzer ferromagnetic resonance. It is demonstrated that the doping of a NiFe film by a small amount of rare earth elements (Holmium, Terbium and Dysprosium) greatly effects its magnetic relaxation rate. This additional damping is proportional to the doping level. Compared to the pure NiFe film it is possible to increase the damping parameter of the magnetic film by two orders of magnitude. On the other hand Gadolinium as a dopant has no influence on the damping parameter. For small dopant concentrations the in and out-of-plane FMR measurements at various frequencies can be well described by the same damping parameter. This is expected for the Gilbert damping term in the equation of motion. Therefore the increased damping can be attributed to an increased rate of transfer of angular momentum from the spin system to the lattice.

  19. High temperature oxidation of iron-chromium alloys

    Mikkelsen, Lars


    The high temperature oxidation of the ferritic alloy Fe78Cr22 has been investigated in the present work. The effect of small alloying additions of cerium and/or silicon was also investigated. The alloys were oxidized at 973, 1173 and 1373 K in either air or a hydrogen/argon mixture. The various reaction atmospheres contained between 0.02 and 50% water vapour. The oxide scales formed on the various alloys at 973 K consisted of thin chromia layers. The oxide scales grown on the alloys at 1173 K also consisted of a chromia layer. The microstructure of the chromia scales was found to depend on the reaction atmosphere. The chromia scales grown in hydrogen/argon atmospheres formed oxide whiskers and oxide ridges at the surface of the scales, while the chromia scales grown in air formed larger oxide grains near the surface. This difference in oxide microstructure was due to the vaporization of chromium species from the chromia scales grown in air. Two different growth mechanisms are proposed for the growth of oxide whiskers. The growth rate of the chromia scales was independent of the oxygen activity. This is explained by a growth mechanism of the chromia scales, where the growth is governed by the diffusion of interstitial chromium. The addition of silicon to the iron-chromium alloy resulted in the formation of silica particles beneath the chromia scale. The presence of silicon in the alloy was found to decrease the growth rate of the chromia scale. This is explained by a blocking mechanism, where the silica particles beneath the chromia scale partly block the outwards diffusion of chromium from the alloy to the chromia scale. The addition of cerium to the iron-chromium alloy improved the adhesion of the chromia scale to the alloy and decreased the growth rate of chromia. It was observed that the minimum concentration of cerium in the alloy should be 0.3 at.% in order to observe an effect of the cerium addition. The effect of cerium is explained by the &apos

  20. High temperature oxidation of iron-chromium alloys

    Mikkelsen, Lars


    The high temperature oxidation of the ferritic alloy Fe78Cr22 has been investigated in the present work. The effect of small alloying additions of cerium and/or silicon was also investigated. The alloys were oxidized at 973, 1173 and 1373 K in either air or a hydrogen/argon mixture. The various reaction atmospheres contained between 0.02 and 50% water vapour. The oxide scales formed on the various alloys at 973 K consisted of thin chromia layers. The oxide scales grown on the alloys at 1173 K also consisted of a chromia layer. The microstructure of the chromia scales was found to depend on the reaction atmosphere. The chromia scales grown in hydrogen/argon atmospheres formed oxide whiskers and oxide ridges at the surface of the scales, while the chromia scales grown in air formed larger oxide grains near the surface. This difference in oxide microstructure was due to the vaporization of chromium species from the chromia scales grown in air. Two different growth mechanisms are proposed for the growth of oxide whiskers. The growth rate of the chromia scales was independent of the oxygen activity. This is explained by a growth mechanism of the chromia scales, where the growth is governed by the diffusion of interstitial chromium. The addition of silicon to the iron-chromium alloy resulted in the formation of silica particles beneath the chromia scale. The presence of silicon in the alloy was found to decrease the growth rate of the chromia scale. This is explained by a blocking mechanism, where the silica particles beneath the chromia scale partly block the outwards diffusion of chromium from the alloy to the chromia scale. The addition of cerium to the iron-chromium alloy improved the adhesion of the chromia scale to the alloy and decreased the growth rate of chromia. It was observed that the minimum concentration of cerium in the alloy should be 0.3 at.% in order to observe an effect of the cerium addition. The effect of cerium is explained by the &apos

  1. 稀土-低熔点合金复合变质处理对超高碳钢微观组织及力学性能的影响%Influence of Multiple Modifier Containing Rare Earths and Low Melting-Point Alloy on Microstructure and Mechanical Properties of Ultrahigh Carbon Steel

    刘坤鹏; 姜荣票; 敦小龙; 徐建秋; 王伟; 刘华山


    Ultrahigh carbon steel containing 1.9% C was modified with multiple modifier containing rare earths and low melting alloy. Microstructure and mechanical properties of ultrahigh carbon steel were studied with OM, SEM, EDS and DSC. The results showed that the continuous eutectic carbide network structure of the ultrahigh carbon steel was broken up, and the austenite grains became much finer after modification. Because Ce2O2S had much negative Gibbs energy, Ce was easy to react with 0 and S to form Ce2O2S in the steel. The austenitizing temperature was raised by addition of RE and low melting-point alloy which were the elements of strongly promoting and stabilizing the pearlite. After quenched and tempered, the isolated carbides were dispersed homogeneously in the martensite matrix. By multiple modification, the impact toughness of the steel ingot was greatly increased from 5. 8 J*cm"2 to 12.5 J'cm"2 with hardness kept about HRC = 65, indicating well comprehensive mechanical properties.%采用自制的稀土-低熔点合金对一种含碳量为1.9%的超高碳钢进行了变质处理,通过OM,SEM,EDS,DSC研究了变质处理和热处理工艺对超高碳钢的微观组织和力学性能的影响.结果表明:超高碳钢经变质处理后,共晶碳化物断网,获得了不连续的块状碳化物,初生奥氏体晶粒明显细化;由于Ce2O2S的吉布斯自由能负值较大,其稳定性较高,因此,稀土元素与O,S在钢中最易形成的稀土氧硫化合物为Ce2O2S;同时稀土与低熔点合金元素的加入,是强烈促进珠光体的元素,具有稳定珠光体的作用,提高了奥氏体化温度;经淬火与低温回火后,获得了马氏体基体上分布着弥散均匀、细小的不连续断网碳化物,冲击韧性得到了明显提高,其ak值由5.8 J·cm-2增加到12.5 J·cm-2,且硬度值基本保持HRC=65,获得了良好的综合力学性能.

  2. High-strength iron aluminide alloys

    McKamey, C.G.; Maziasz, P.J.


    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  3. Ab initio modeling of decomposition in iron based alloys

    Gorbatov, O. I.; Gornostyrev, Yu. N.; Korzhavyi, P. A.; Ruban, A. V.


    This paper reviews recent progress in the field of ab initio based simulations of structure and properties of Fe-based alloys. We focus on thermodynamics of these alloys, their decomposition kinetics, and microstructure formation taking into account disorder of magnetic moments with temperature. We review modern theoretical tools which allow a consistent description of the electronic structure and energetics of random alloys with local magnetic moments that become totally or partially disordered when temperature increases. This approach gives a basis for an accurate finite-temperature description of alloys by calculating all the relevant contributions to the Gibbs energy from first-principles, including a configurational part as well as terms due to electronic, vibrational, and magnetic excitations. Applications of these theoretical approaches to the calculations of thermodynamics parameters at elevated temperatures (solution energies and effective interatomic interactions) are discussed including atomistic modeling of decomposition/clustering in Fe-based alloys. It provides a solid basis for understanding experimental data and for developing new steels for modern applications. The precipitation in Fe-Cu based alloys, the decomposition in Fe-Cr, and the short-range order formation in iron alloys with s-p elements are considered as examples.

  4. Iron-nickel alloy from iron meteorite Chinga studied by Moessbauer spectroscopy with high velocity resolution

    Oshtrakh, M. I., E-mail:; Grokhovsky, V. I.; Abramova, N. V. [Ural State Technical University-UPI, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Semionkin, V. A. [Ural State Technical University-UPI, Faculty of Experimental Physics (Russian Federation); Milder, O. B. [Ural State Technical University-UPI, Radio-Technical Department (Russian Federation)


    Study of iron-nickel alloy from iron meteorite Chinga using Moessbauer spectroscopy with improved velocity resolution (measurement and presentation in 4,096 channels) revealed six magnetic components which may be related to various {alpha}-Fe(Ni, Co) and {gamma}-Fe(Ni, Co) phases while previous study with low velocity resolution (in 512 channels) revealed only three magnetic components. This new result was in agreement with the scanning electron microscopy study.

  5. High-strength iron aluminide alloys

    McKamey, C.G.; Marrero-Santos, Y.; Maziasz, P.J.


    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile density due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications, despite their excellent corrosion properties. Improvements in room temperature tensile ductility have been realized mainly through alloying effects, changes in thermomechanical processing to control microstructure, and by control of the specimen`s surface condition. Ductilities of 10-20% and tensile yield strengths as high as 500 MPa have been reported. In terms of creep-rupture strength, small additions of Mo, Nb, and Zr have produced significant improvements, but at the expense of weldability and room-temperature tensile ductility. Recently an alloy containing these additions, designated FA-180, was shown to exhibit a creep-rupture life of over 2000 h after a heat treatment of 1 h at 1150{degrees}C. This study presents the results of creep-rupture tests at various test temperatures and stresses and discusses the results as part of our effort to understand the strengthening mechanisms involved with heat treatment at 1150{degrees}C.

  6. Iron/Phosphorus Alloys for Continuous Casting

    Dufresne, E. R.


    Continuous casting becomes practicable because of reduced eutectic temperature. Experimental ferrous alloy has melting point about 350 degrees C lower than conventional steels, making possible to cast structural members and eliminating need for hot rolling. Product has normal metal structure and good physical properties. Process used to make rails, beams, slabs, channels, and pipes.

  7. A study on the deactivation of USY zeolites with different rare earth contents

    Henriques, C.A.; Santos, J.O.J. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Polato, C.M.S.; Valle, Murta; Aguiar, E.F.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica; Monteiro, J.L.F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Nucleo de Catalise


    The deactivation of USY zeolites different rare earth contents due to the coke formed n-heptane at 450 deg C was studied. The results show that the presence of rare earth elements decreases the cracking and coking activities, increasing catalytic stability. However, reaction selectivity was not significantly influenced. The greater the rare earth content, the lower the cocking rates and the coke contents. The TPO/DSC profiles suggested that the catalytic effect of the rare earth elements promoted coke oxidation. (author)

  8. Chinalco and China National Administration of Coal Geology Jointly Built Guangxi Rare Earth Industrial Base


    <正>On June 3,Chinalco and China National Administration of Coal Geology signed cooperation agreement for strategic cooperation&cooperation agreement between Chinalco Guangxi Nonferrous Rare Earth Development Company and Xuzhou Jin Shi Pengyuan Rare Earth Material Factory.According to the agreement,both sides would jointly support Chinalco Guangxi Nonferrous Rare Earth Development Company and Xuzhou Jin Shi Pengyuan Rare Earth Material Factory to carry out comprehensive cooperation covering rare

  9. Identification of a cast iron alloy containing nonstrategic elements

    Cooper, C. V.; Anton, D. L.; Lemkey, F. D.; Nowotny, H.; Bailey, R. S.; Favrow, L. H.; Smeggil, J. G.; Snow, D. B.


    A program was performed to address the mechanical and environmental needs of Stirling engine heater head and regenerator housing components, while reducing the dependence on strategic materials. An alloy was developed which contained no strategic elemental additions per se. The base is iron with additions of manganese, molybdenum, carbon, silicon, niobium, and ferro-chromium. Such an alloy should be producible on a large scale at very low cost. The resulting alloy, designated as NASAUT 4G-Al, contained 15 Mn, 15 Cr, 2 Mo, 1.5 C, 1.0 Si, 1.0 Nb (in weight percent) with a balance of Fe. This alloy was optimized for chemistry, based upon tensile strength, creep-rupture strength, fracture behavior, and fatigue resistance up to 800 C. Alloys were also tested for environmental compatibility. The microstructure and mechanic properties (including hardness) were assessed in the as-cast condition and following several heat treatments, including one designed to simulate a required braze cycle. The alloy was fabricated and characterized in the form of both equiaxed and columnar-grained castings. The columnar grains were produced by directional solidification, and the properties were characterized in both the longitudinal and transverse orientations. The NASAUT 4G-Al alloy was found to be good in cyclic-oxidation resistance and excellent in both hydrogen and hot-corrosion resistance, especially in comparison to the baseline XF-818 alloy. The mechanical properties of yield strength, stress-rupture life, high-cycle-fatigue resistance, and low-cycle-fatigue resistance were good to excellent in comparison to the current alloy for this application, HS-31 (X-40), with precise results depending in a complex manner on grain orientation and temperature. If required, the ductility could be improved by lowering the carbon content.

  10. Corrosion of carbon-alloyed iron aluminides

    M Sen; R Balasubramaniam; A V Ramesh Kumar


    The corrosion behaviour of two carbon-alloyed intermetallics of composition Fe–28.1Al–2.1C and Fe–27.5Al–3.7C has been studied and compared with that of binary intermetallics. Potentiodynamic polarization studies indicated that the intermetallics exhibited active–passive behaviour in an acidic solution of pH = 1, whereas they exhibited stable passivity in a buffer solution of pH 8.4. Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides.

  11. Rare-earth transition-metal intermetallics: Structure-bonding-property relationships

    Han, M. K. [Iowa State Univ., Ames, IA (United States)


    The explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding property relationships. The work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe13-xSix system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn{sub 13}-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides Re2-xFe4Si14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi2: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb3Zn3.6Al7.4: Partially ordered structure of Tb3Zn3.6Al7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn39(CrxAl1-x)81

  12. Rare-Earth Transition-Metal Intermetallics: Structure-bonding-Property Relationships

    Han, Mi-Kyung [Iowa State Univ., Ames, IA (United States)


    Our explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding-property relationships. Our work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe13-xSix system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn13-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides RE2-xFe4Si14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi2: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb3Zn3.6Al7.4: Partially ordered structure of Tb3.6Zn13-xAl7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn39(CrxAl1-x

  13. The Association of China Rare Earth Industry Founded to Cope with International Trade Disputes


    <正>On April 8,the long-awaited Association of China Rare Earth Industry was eventually founded in Beijing.The association is composed of 155 members including Chinalco, Minmetals,Baotou Steel Group and Ganzhou Rare Earth,etc.,covering nearly all rare earth


    K. V. Kobyakov


    Full Text Available It is shown that for improvement of physical-mechanical properties of the cast products which have hard usage, the boron carbide, which can be used at carrying out process of thermo-chemical treatment of cast products of iron-carbon alloy, is of great interest.

  15. Investigations into Rare Earth Oxide Use and Behaviour

    Pryce, Owen


    The use of tracers which are applied to soils (distinguishable from tracers naturally present in soils) is increasing. Rare earth oxides (REOs) are the most prevalent of the sediment tracers used to tag soils in this manner. REOs have been applied in a host of different countries, at a range of scales e.g. over watersheds in the USA (Polyakov and Nearing, 2004; Kimoto et al., 2006); to examine rill erosion in China (Li et al., 2006); and to investigate the importance of topographical features in arable fields in the EU (Stevens and Quinton, 2008). Many successful experiments have been conducted using the suit of REO tracers, yielding important information on the behaviour of eroding sediments. However, the majority of publications have focused upon application of REO tracers, applying the tagging and extraction methods developed by Zhang et al., (2001, 2003). Furthermore, the techniques presently being used are known to generate methodological inaccuracies, such as tracer enrichment and non-uniform REO distributions on experimental plots, and analytical interferences when ICP-MS is used for tracer quantification. Unanswered questions regarding the use of REO tracers include: i) what is the effect upon soil of REO tagging?; ii) how is a uniform distribution of REOs in tagged soil achieved? iii) which is the most suitable way of applying REOs, to experimental plots of different scale, and to meet different objectives?; iv) which REOs are unsuitable for sediment tracing?; v) what is the most precise and efficient method of extracting REO tracers from sediments? vi) is the transport behaviour of REO tracers comparable to untagged soils? In an attempt to answer some of these questions, investigations have been conducted into the effect upon soil particle size of different methods of REO tagging. The ability of these methods to provide uniform distributions of REOs in the tagged soil was calculated. The accuracy and precision of published (Zhang et al., 2003; Stevens and

  16. Radiation effects on rare-earth doped optical fibers

    Girard, S.; Marcandella, C. [CEA Bruyeres-le-Chatel, DIF 91 (France); Ouerdane, Y.; Tortech, B.; Boukenter, A.; Meunier, J.P.; Vivona, M. [Lab. Hubert Curien, CNRS, 42 - Saint-Etienne (France); Vivona, M.; Robin, Th.; Cadier, B. [iXFiber SAS, 22 - lannion (France)


    In this paper, we reviewed our previous work concerning the responses of rare-earth (RE) doped fibers (Yb, Er and Er/Yb) to various types of radiations like gamma-rays, X-rays and protons. For all these harsh environments, the main measured macroscopic radiation-induced effect is an increase of the linear attenuation of these waveguides due to the generation of point defects in the RE-doped core and silica-based cladding. To evaluate the vulnerability of this class of optical fibers for space missions, we characterize the growth and decay kinetics of their radiation-induced attenuation (RIA) during and after irradiation for various compositions. Laboratory testing reveals that this class of optical fibers is very sensitive to radiations compared to passive (RE-free) samples. As a consequence, despite the small length used for space applications, the understanding of the radiation-induced effects in this class of optical fibers becomes necessary before their integration as part of fiber-based systems like gyroscopes or communication systems. In this paper, we more particularly discussed about the relative influence of the rare-earth ions (Er{sup 3+} and/or Yb{sup 3+}) and of the glass matrix dopants (Al, P, ... ) on the optical degradation due to radiations. This has been done by using a set of five prototype optical fibers designed by the fiber manufacturer iXFiber SAS to enlighten the role of these parameters. Additional spectroscopic tools like con-focal microscopy of luminescence are also used to detect possible changes in the spectroscopy of the rare-earth ions and their consequences on the functionality of the active optical fibers. (authors)

  17. Solution thermodynamics of rare-earth metal ions - physicochemical study-

    Amerkhanova, Sh K; Shlyapov, R M; Uali, A S [Buketov Karaganda state university, University str., 28, Karaganda, 100028 (Kazakhstan)], E-mail:


    The results of the studying of interactions in multicomponent systems 'polyvinyl alcohol (PVA) - rare-earth element ion - nitrate of sodium - water' are represented. It is established that for rubidium (I) ions temperature and ionic strength is render destroying action, and for yttrium (III) ions the influence of these factors has return character which is connected with features of an electronic structure of metal ion. It is revealed that a dominating role of non-electrostatic formation composed, hence, the formation of donor-acceptor connection of 'metal - ligand' occurs through atom of oxygen.

  18. Recent Progress on Nanoscale Rare Earth Luminescent Materials


    1 Results The size of nanoscale rare earth luminescent materials is often smaller than that of the excitement or emission wavelength,and it has amazing surface state density. Therefore,it shows a lot of new luminescent phenomena such as the shift of CTS,the broadening of emission peaks,the variation of fluorescent lifetimes and quantum efficiency,and the increase of quenching concentration.It is not only of academic interest but also of technological importance for advanced phosphor applications to rese...

  19. Thermoluminescence dosimetry of rare earth doped calcium aluminate phosphors

    K Madhukumar; K Rajendra Babu; K C Ajith Prasad; J James; T S Elias; V Padmanabhan; C M K Nair


    The thermoluminescence (TL) properties of calcium aluminate (CaAl2O4) doped with different rare earth ions have been studied and their suitability for radiation dosimetry applications is discussed. It is observed that monocalcium aluminate doped with cerium is a good dosimeter having linear response up to about 4 kGy of radiation doses. Dopant concentration of 0.25 mol% cerium gives maximum TL emission. The well-defined single peak observed at 295°C can be advantageously used for high temperature dosimetry applications.

  20. Synthesis and Characterization of Rare Earth Complexes of Ferrocenylcarbonylhydrazine

    边占喜; 董彬; 李保国


    Rare earth complexes of ferrocenylcarbonylhydrazine Ln(FH)x(ClO4)3*nH2O (where Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, x=3; Ln = Er, Tm, Yb, Lu, x=4; n=2~6, FH=ferrocenylcarbonylhydrazin) were synthesized and characterized by elemental analyses, MS, IR and 1H NMR spectra. The ligand FH is bidentate, coordinating through the carbonyl oxygen and the amino nitrogen atom. The redox properties of the ligand and its complexes were investigated using cyclic voltammetric method. The solid state fluorescence spectra of Sm, Tb and Dy complexes were also studied.

  1. Electron-phonon coupling in the rare-earth metals

    Skriver, Hans Lomholt; Mertig, I.


    We have estimated the strength of the mass enhancement of the conduction electrons due to electron-phonon interaction in the rare metals Sc, Y, and La–Lu. The underlying self-consistent energy bands were obtained by means of the scalar relativistic linear-muffin-tin-orbital method, and the electron......-phonon parameters were calculated within the Gaspari-Gyorffy formulation. For the heavier rare earths Gd–Tm spin polarization was included both in the band-structure calculations and in the treatment of the electron-phonon coupling to take into account the spin splitting of the conduction electrons induced by the 4...

  2. Resonance electronic Raman scattering in rare earth crystals

    Williams, G.M.


    The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce/sup 3 +/(4f/sup 1/) in single crystals of LuPO/sub 4/ and Er/sup 3 +/(4f/sup 11/) in single crystals of ErPO/sub 4/. 134 refs., 92 figs., 33 tabs.

  3. Preparation of Rare-Earth Composite Ferrite Magnetic Fluid

    蒋荣立; 刘永超; 刘守坤; 鞠明礼


    Water-based rare-earth ferrite (RexFe3-xO4)magnetic fluids were prepared by chemical co-precipitation method. The result shows that saturation magnetic intensity of ferrite magnetic fluids can be improved by adding Dy3+ and the saturation magnetic intensity will reach the highest if n(Fe)∶n(Dy3+)=30∶1. The modification and formation mechanism of RexFe3-xO4 particles is discussed in detail. The physicochemical properties are investigated by the Gouy magnetic balance, IR, TEM, XRD, and EDX, etc.

  4. Review, Intelligence and Development of Rare Earths during Biological Evolution

    Qiu Guanming; Li Wei; Zhang Ming; Li Zhe; Yan Changhao; Li Yourong; Ding Guohui


    The relationship between organism and rare earth elements (REE) viewed from evolution was discussed.Some metal ions play key roles in biological functions, however, as the illustration in this article shows, with powerful affinities for oxygen and similar radius, REE can display equally or even more important functions in terms of its biological functions. These attractive characteristics have called more public attention and lead to many applications in agriculture, medicine fields, etc. Furthermore, the article employed the concept of entropy to discuss the dosage effect of REE on organism and the possibility whether REE can become a portion of organism during the evolution.

  5. Mother Lode: The Untapped Rare Earth Mineral Resources of Vietnam


    hundreds of Bq/m 3 of air; the recommended safety limits for civilian exposure are 3.5 mSv/year and 0.15 Bq/m 3 , respectively. 37 REO Mining – a...Commission for Asia and the Pacific. Atlas of Mineral Resources of the ESCAP Region, Vol. 6, Viet Nam. ST/ESCAP/831. Bangkok : UNESCAP, 1990. “US$ 35.5... Bangkok ), July 19, 2013. ProQuest (1400734925). “VINACOMIN and Japanese Firm to Exploit and Process Rare Earth in Lai Chau.” Vietnam National

  6. Electron microscopy of microwave-synthesized rare-earth chromites

    Schmidt, Rainer; Prado-Gonjal, Jesus; Avila, David; Amador, Ulises; Moran, Emilio


    The perovskite rare-earth (RE) chromite series (RE)CrO3 (RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, Lu) has been synthesized in our laboratory using microwave techniques. In this work we will demonstrate how X-ray diffraction (XRD), Rietveld refinement of XRD pattern and complementary High Resolution Transmission Electron Microscopy (HRTEM) were used to confirm that the desired crystal structure had been formed. Field-emission scanning electron microscopy (FE-SEM) gave clear ...

  7. Effect of Rare Earth Elements on Quantity Growth of Ctrps

    张自立; 常江; 等


    The effects of rare earth on the growth of rice,rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization(OECD),and the EC50(median growth concenrtation)values were obtained,The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybeanin yellow fouvo-aquic soil is higher with stronger poison effects.Compared with other heavy metals such as Hg,Cd,Pb,As,the poison of RE on crops in weaker.

  8. Effect of Rare Earth Elements on Quantity Growth of Crops

    张自立; 常江; 汪成胜; 柴绍明; 韩修明; 李瑞


    The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and De velopment organization (OECD), and the EC50(median growth concentration)value s were obtained . The inhibition of RE on the growth of rice and rape in red soil and on the gro wth of soybean in yellow fluvo-aquic soil is higher with stronger poison effect s. Compared with other heavy metals such as Hg, Cd, Pb, As, the poison of RE on crops is weaker.

  9. Synthesis and luminescence of some rare earth metal complexes

    Bochkarev, Mikhail N.; Pushkarev, Anatoly P.


    In the present paper the synthesis, photoand electroluminescent properties of new rare earth metal complexes prepared and studied at the Razuvaev Institute of Organometallic Chemistry during the last decade are reviewed. The obtained compounds give luminescence in UV, visible and NIR regions. The substituted phenolates, naphtholates, mercaptobenzothiazolate, 8-oxyquinolinolate, polyfluorinated alcoholates and chalcogenophosphinates were used as ligands. The synthesis and structure of unusual three-nuclear sulfidenitride clusters of Nd and Dy are described. The new excitation mechanism of ytterbium phenolates and naphtholates, which includes the stage of reversible reduction of Yb to divalent state and oxidation of the ligands in the excitation process, is discussed.

  10. Luminescence enhancement of rare earth ions by metal nanostructures



    Well-ordered metal structures,i.e.arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used.These arrays were prepared by the metal evaporation on track membranes.Calculations of resonance frequencies of tips regarded as semispheroids were done taking into account the interaction between dipoles of tips.They were used to discuss experimental results for media with Eu(NO3)3·6H2O salt basing on data for bulk silver dielectric function.

  11. Influence of Rare Earths on Contact Fatigue of Rail Steels


    Rail/wheel contact fatigue of NbRE rail, Nb rail and U74 rail was investigated using contact fatigue tester. Microstructure and morphology as well as microhardness in the fatigue profiles were analyzed by scanning electron microscope and Vickers hardness respectively. The experimental results show that rare earths are able to delay the initiation and the propagation of fatigue cracks and postpone the surface shelling or spalling, even more, to reduce the crack propagation angle and the crack propagation depth in steady state as well as the plastic deformation area, and to improve work-hardening of the rail steel.

  12. Charge Penetration Effects in Rare-Earth Crystal Fields.


    Interactions, 3. Three-Parameter Theory of Crystal Fields, Harry Diamond Laboratories HDL-TR-1673 (June 1975). 2R. M. Sternheimer , Phys. Rev., 84 (1951...R. M. Sternheimer , Phys. Rev., 84 (1951), 244. (3) R. E. Watson and A. J. Freeman, Phys. Rev., 135 (1964), A1209. (4) D. Sengupta and J. 0. Artman...A RARE-EARTH ION INTO THE CHARGE DI! THE RESULTS ARE CAST INTO A FORM REMINISCENT OF THE STERNHEIMER SHIELDING FA( A PRIME NM(R TO THE NTH POWER) TO

  13. Effects of rare earth elements on properties of AB5-type electrode materials at different temperature


    Discharge property is an important factor to evaluate electrode materials. The discharge capacity of the hydrogen-storing alloys are not only influenced by its thermodynamic property but also closely related to its dynamic property. When the temperature changes, the degrees of influence of the above-mentioned two factors on the discharge performance vary accordingly. As a consequence, adjusting compositions of the alloys to make them have good discharge performance under a relatively wide range of temperature is of great significance. On the basis of great deal of experimental investigation, the optimum combination of rare earth elements in hydrogen-storing electrode materials using at-30-55℃ is determined and the relationships between the cell parameters and discharge performance of alloys at -30℃ are discussed. Additionally, the DFEC calculation method has been improved to predict the discharge capacities, which is in good agreement with the experimental ones. This is of theoretical significance in investigating new hydrogen-storing alloys of the AB5 type.

  14. Enhanced Corrosion Resistance of Iron-Based Amorphous Alloys

    Rebak, R B; Day, S D; Lian, T; Aprigliano, L F; Hailey, P D; Farmer, J C


    Iron-based amorphous alloys possess enhanced hardness and are highly resistant to corrosion, which make them desirable for wear applications in corrosive environments. It was of interest to examine the behavior of amorphous alloys during anodic polarization in concentrated salt solutions and in the salt-fog testing. Results from the testing of one amorphous material (SAM2X5) both in ribbon form and as an applied coating are reported here. Cyclic polarization tests were performed on SAM2X5 ribbon as well as on other nuclear engineering materials. SAM2X5 showed the highest resistance to localized corrosion in 5 M CaCl{sub 2} solution at 105 C. Salt fog tests of 316L SS and Alloy 22 coupons coated with amorphous SAM2X5 powder showed resistance to rusting. Partial devitrification may be responsible for isolated pinpoint rust spots in some coatings.

  15. Effect of mixed rare earth oxides and CaCO3 modification on the microstructure of an in-situ Mg2Si/Al-Si composite

    LIU Zheng; LIN Jixing; JING Qingxiu


    The effects of mixed rare earth oxides and CaCO3 on the microstructure of an in-situ Mg2Si/Al-Si hypereutectic alloy composite were investigated by optical microscope, scanning electron microscope, and energy dispersive spectrum analysis. The results showed that the morphology of the primary Mg2Si phase particles changed from irregular or crosses to polygonal shape, their sizes decreased from 75 μm to about 25 μm, and the compound of both the oxide and CaCO3 was better than either the single mixed rare earth oxides or CaCO3.

  16. Structural and crystal chemical properties of rare-earth double phosphates and rare-earth titanate pyrochlores

    Farmer, J. Matt

    Alkali rare-earth double phosphates have been studied for use as long-wavelength scintillators for gamma-ray detection using Si photodiodes. These compounds exhibit layered crystal structures, built from roughly hexagonal atomic layers in the sequence lanthanide, phosphate-alkali, alkali, alkali-phosphate. Details of the crystal symmetry depend on the relative sizes of the rare-earth and alkali metal ions. Single-crystal X-ray diffraction (SXRD) has been used to study these structures at room temperature for K3RE(PO4) 2 (where RE = Lu-Ce, Y, and Sc). The compound K3Lu(PO 4)2 crystallizes with a hexagonal unit cell, space group P-3. The Lu ion is six-coordinated to the oxygen atoms of the phosphate groups. Two lower-temperature phases of K3Lu(PO4) 2 were observed and characterized. The lower-temperature transition results in an increase in coordination of the Lu ion to seven fold. This new structure is isostructural with the room-temperature form of K3Yb(PO 4)2. High-temperature powder neutron diffraction and high-temperature powder XRD have revealed a large thermal expansion anisotropy for K3Lu(PO4)2. The K3RE(PO 4)2 formation enthalpies were determined using high-temperature oxide-melt solution calorimetry. The formation enthalpy from oxides becomes more exothermic with increasing rare-earth radius. Rare-earth titanates, RE2Ti2O7 (where RE = a rare-earth), with the pyrochlore structure are currently being studied for use as potential nuclear, actinide-rich waste forms. Single-crystals were synthesized using a high-temperature flux technique and characterized using single-crystal X-ray diffraction. The cubic lattice parameters display an approximately linear correlation with the RE-site cation radius. The Sm and Eu titanates exhibit a covalency increase between the REO8 and TiO6 polyhedra resulting in a deviation from the increasing linear lattice parameter through the series. Gd2Ti2O7 exhibits the lowest 48f oxygen positional parameter, an effect that can be

  17. Review and outlook for China rare earth industry in recent years

    By Lihua ZHANG; Mingsheng YANG; Xiaofang LIU


    @@ Guided by related policies, China rare earth industry is actively transferring its economic development pattern in recent two years.Series of effective economic stimulus policies and measures were adopted, which further standardize rare earth mining, production and export market.Chinese rare earth industry had finally overcome difficulties brought by global financial crisis and production and marketing in the industry were gradually improved.In 2009, rare earth business thoroughly reversed the unprofitable situation.Total production value exceeded 24 billion yuan in the year.With global economy recovery in 2010, rare earth industry entered into a rapid development period.

  18. Criticality of iron and its principal alloying elements.

    Nuss, Philip; Harper, E M; Nassar, N T; Reck, Barbara K; Graedel, T E


    Because modern technology depends on reliable supplies of a wide variety of materials and because of increasing concern about those supplies, a comprehensive methodology was created to quantify the degree of criticality of the metals of the periodic table. In this paper, we apply this methodology to iron and several of its main alloying elements (i.e., vanadium, chromium, manganese, and niobium). These elements represent the basic metals of any industrial society and are vital for national security and economic well-being. Assessments relating to the dimensions of criticality - supply risk, vulnerability to supply restriction, and environmental implications - for 2008 are made on the global level and for the United States. Evaluations of each of the multiple indicators are presented, with aggregate results plotted in "criticality space", together with Monte Carlo simulation-derived "uncertainty cloud" estimates. Iron has the lowest supply risk, primarily because of its widespread geological occurrence. Vanadium displays the highest cradle-to-gate environmental implications, followed by niobium, chromium, manganese, and iron. Chromium and manganese, both essential in steel making, display the highest vulnerability to supply restriction, largely because substitution or substitution at equal performance is not possible for all end-uses. From a comprehensive perspective, we regard the overall criticality as low for iron and modest for the alloying elements we evaluated.

  19. Homometallic rare-Earth metal phosphinidene clusters: synthesis and reactivity.

    Wang, Kai; Luo, Gen; Hong, Jianquan; Zhou, Xigeng; Weng, Linhong; Luo, Yi; Zhang, Lixin


    Two new trinuclear μ3 -bridged rare-earth metal phosphinidene complexes, [{L(Ln)(μ-Me)}3 (μ3 -Me)(μ3 -PPh)] (L=[PhC(NC6 H4 iPr2 -2,6)2 ](-) , Ln=Y (2 a), Lu (2 b)), were synthesized through methane elimination of the corresponding carbene precursors with phenylphosphine. Heating a toluene solution of 2 at 120 °C leads to an unprecedented ortho CH bond activation of the PhP ligand to form the bridged phosphinidene/phenyl complexes. Reactions of 2 with ketones, thione, or isothiocyanate show clear phospha-Wittig chemistry, giving the corresponding organic phosphinidenation products and oxide (sulfide) complexes. Reaction of 2 with CS2 leads to the formation of novel trinuclear rare-earth metal thione dianion clusters, for which a possible pathway was determined by DFT calculation. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Progress on Study of Luminescence of Rare Earth Organic Chelates

    杨燕生; 安保礼; 龚孟濂; 史华红; 雷衡毅; 孟建新


    Based on the investigation of the luminescence of a series of rare earth organic chelates, some relationships between luminescence and the structure of the chelates were proposed: the intensity of sensitized luminescence of central lanthanide ions(Ln3+) in a rare earth organic chelate depends on (1)the suitability of the energy gap between the excited triplet energy level of the ligands and the lowest excited energy level of Ln3+ ions; (2)the rigidity and planarity of the structure of the chelate molecule; (3)the existence of a suitable secondary ligand which may increase rigidity and the stability of the chelate molecule; and (4) the existence of a suitable π-conjugated system in the chelate molecule. According to the above relationships, 25 novel organic ligands were designed and synthesized, and their lanthanide chelates were prepared. Investigation of the photoluminescence for the new chelates shows that some of the chelates are strongly luminescent, and are applied to fluoroimmunoassay for determination of human immunoglobulin(IgG), to preparation of fluorescent plastics, and to determination of growth hormone for plants. Two novel spectroscopy-probe techniques for structure of coordination compounds and biological molecules were proposed and developed based on vibronic spectroscopy of Tb3+ complexes and fluorescence of Ce3+.