Rare Earth Elements Yb Research Articles

Effects of Hot Extrusion on the Microstructure and Wear Properties of A380-Yb Alloy

A380-Yb (Ytterbium) alloy was prepared by the ultrasonic melting casting method, and effects of hot extrusion on the microstructure and wear properties of the alloy were studied. The results indicate that the addition of rare earth Yb can refine the microstructure of the matrix alloy. After hot extrusion (extrusion ratio of 22.56) of the as-cast A380-Yb alloy, the secondary phase in its microstructure was further refined and the distribution became more uniform. EBSD (electron backscatter diffraction) organizational analysis shows that the average GND (geometrically necessary dislocation) density of extruded rare earth aluminum alloy is significantly increased, by 16.5 times that of the cast matrix alloy. In addition, there are a large number of grains parallel to the <111> orientation and <001> orientation in the extrusion direction. The alloy undergoes dynamic recrystallization during hot extrusion, and the proportion of small-angle grain boundaries is significantly reduced. Under the same friction and wear conditions, the wear rate and average friction and wear coefficient of the extruded rare earth aluminum alloy are relatively small, reduced by 53.8% and 42.6%, respectively, compared to the cast matrix alloy. Its wear mechanism is mainly abrasive wear and slight plastic deformation. In addition, the study also found that under fixed other wear conditions, as the friction speed increases, the wear rate of the extruded rare earth aluminum alloy shows a trend of first decreasing and then increasing. However, with the increase in load, its wear rate gradually increases, and the change in wear morphology is consistent with the trend of wear rate. When the wear rate is high, the wear mechanism of the extruded aluminum alloy is mainly delamination wear and adhesive wear, and is sometimes accompanied by severe plastic deformation. When the wear rate is low, its wear mechanism is mainly abrasive wear.

Benign separation, adsorption, and recovery of rare-earth Yb(III) ions with specific ligand-based composite adsorbent

This study developed a ligand-based composite adsorbent (ComA) for efficient Ytterbium (Yb(III)) adsorption and recovery from waste samples. The organic ligand of 1E,1`E,1``E,1```E (tetrakis(3-carboxysalicylidene)) naphthalene-1,2,5,5-tetramine (TSNT) was synthesized and TSTN was successfully immobilized onto mesoporous silica by a direct immobilization approach. The experiment conditions were optimized based on contact time, solution acidity, initial Pb(II) concentration pH value, and diverse metal salt concentrations. The Europium (Eu(III)) ion was selected from the lanthanides (Ln(III)) series for green and robust adsorption and recovery based on the adsorption, complexation, and selectivity tendency from the standpoint of the pH-dependent factor. The chemical compound of TSTN consisted of O- and N-donor atoms and was able to make stable complexation with Ln(III) ions in optimum conditions due to the open functionality of the ComA. The experimental data revealed that the maximum Yb(III) adsorption was possible at pH 5.0. The presence of other cations and anions did not adversely affect the Yb(III) capturing by the adsorbent. The bonding mechanism suggested that O- and N-donor atoms of TSTN were strongly coordinated to Eu(III) with a 2:1 ratio complexation. The maximum adsorption capacity was determined to be as high as 149.27 mg/g. The extraction of Yb(III) ions from the saturated adsorbent was possible with 0.25 M HNO3. The regenerated adsorbent that remained maintained the high selectivity to Yb(III) ions and exhibited almost the same adsorption capacity as that of the original adsorbent. However, the adsorption efficiency slightly decreased after several cycles. Therefore, the proposed adsorbent offered a cost-effective material and may be considered a viable alternative for effective adsorption and recovery of Yb(III) ions from water samples.

Influence of B-site rare-earth Yb cation on the crystal structure and microwave dielectric properties of Ca3Yb2Ge3O12 garnet ceramics

In this work, garnet structured Ca3Yb2Ge3O12 ceramics with a space group of Ia-3d were synthesized by a solid-state reaction method. Rietveld refinement analysis demonstrated that Yb3+with small ionic radius and large electronegativity entered the B-sites and shortened the bond length of B–O and Ge–O. The bond valence and P-V-L theory analysis results showed that Ca cations with a weakened rattling effect exerted a critical effect on the dielectric constant, and the Ge–O bond was the main factor that influenced dielectric loss. Ca3Yb2Ge3O12 with a high relative density (98.2%) and excellent microwave dielectric properties (εr= 10.2, Q × f = 98,400 GHz, τf = -48 ppm/°C) was obtained at 1360 °C for 4 h. Furthermore, the intrinsic dielectric constant and dielectric loss (εr =10.12, Q × f = 101,900 GHz) of Ca3Yb2Ge3O12 were obtained by infrared reflectivity spectroscopy.

Dissolution and structural evolution of Yb2O3 in eutectic LiF–YbF3 molten salts

The dissolution of Yb2O3 in eutectic LiF–YbF3 systems and resulting structural changes in the systems are key factors ensuring efficient electrolysis during the synthesis of rare-earth Yb alloys. In this study, isothermal saturation was used to determine the solubilities of Yb2O3 in eutectic LiF and LiF–YbF3 molten salts. The interactions between the components of the LiF–YbF3–Yb2O3 system were studied using a combination of quantum chemical calculations, thermodynamic analysis, and experimental verification. The structural evolution of the system was analyzed using high-temperature Raman spectroscopy and ab initio molecular dynamics simulations during the integration of Yb2O3 into a eutectic LiF–YbF3 molten salt. The main phases in the LiF–(21 mol.%)YbF3 system saturated with Yb2O3 consisted of LiF, LiYbF4, and a minimal amount of YbOF and its derivatives. Yb2O3 did not alter the main structure of the LiF–LiYbF4 system, and Li+, F−, and YbF4− were the main ionic forms in the system. The Yb–F bond in YbOF was less stable than the Yb–O bond, and YbOF easily dissociated into YbO+and F−.

Effect of Solution Treatment and Addition of Rare-Earth Yb on the Microstructure and Corrosion Resistance of AlSi11Cu3 Alloy

Effect of Solution Treatment and Addition of Rare-Earth Yb on the Microstructure and Corrosion Resistance of AlSi11Cu3 Alloy

Highly efficient Ni–Mo–P composite rare earth elements electrode as electrocatalytic cathode for oil-based drill sludge treatment

It is considered an effective strategy to improve electrochemical performance that introducing rare elements into metal catalysts, which would provide abundant electrochemical active sites and be a benefit for redox reactions. A new Ni–Mo–P composite electrode material modified with rare earth elements (light rare earth Nd and heavy rare earth Yb) was prepared, evaluating the current density of direct current electrodeposition, the doping ratio of Yb and Nd, and the cyclic voltammetry deposition (CVD) cycle numbers on electrode structure and electrochemical performance. The results showed that the electrode has the most obvious amorphous state, the lowest hydrogen evolution overpotential (41.5 mV vs Ag/AgCl) and charge transfer resistance (15.74 Ω/cm2), and remarkable stability when the molar ratio of Yb and Nd was 8:2 and the 20 cycle numbers under the CVD condition. The electrochemical performance and characterization of the electrode showed that there was a good synergistic effect between rare earth elements (Yb, Nd) and Ni–Mo–P alloys. The oil-based drill sludge (OBDS) treatment indicated that the organic matter content is significantly reduced by using the above-modified electrode as the cathode, and the COD and petroleum removal rate can reach up to 85.4 ± 1.2% and 66.2 ± 5.9%. The effect of degradation for aliphatic hydrocarbon was better than aromatic hydrocarbons and no other intermediates are produced during the degradation, which may eventually mineralize the organic matter. This research provided technical support for the preparation of new Ni–Mo–P electrodes modified with rare earth elements and confirmed that electrocatalytic technology was a suitable method for OBDS treatment.

Enhanced thermoelectric performance of polycrystalline SnSe by doping with the heavy rare earth element Yb

As an environmentally friendly thermoelectric material, SnSe has attracted great attention because of its excellent performance in its single-crystal form. On the other hand, the better mechanical property and lower manufacturing cost of its polycrystalline counterpart with the better mechanical property and lower manufacturing cost can serve as a better candidate for widespread applications. Previous reports on p-type polycrystalline SnSe mainly focus on optimizing the carrier concentration by doping alkali metals or decreasing the lattice thermal conductivity by nanostructuring. Here, we report the effect of Yb doping on the thermoelectric properties of polycrystalline SnSe prepared by solvothermal synthesis. Through introducing Yb, the p-type carrier concentration is increased and the density of states at valence band maximum is distorted, which is revealed by DFT calculation, leading to an increase of the effective mass. Thus, the power factor has been markedly enhanced to 0.78 mW m−1 K−2 at 823 K (about 1.6 times that of undoped SnSe). Moreover, Yb doping in SnSe decreases the lattice thermal conductivity by intensifying the phonon scattering. As a result, a high zT of 1.1 at 823 K in Sn0.98Yb0.02Se is achieved along the in-plane direction. This work provides a new way for improving the thermoelectric properties of SnSe by modifying its valence band structure.

PHOTOLUMINESCENCE OF UNDOPED AND Yb-DOPED GaS SINGLE CRYSTALS IRRADIATED WITH γ-QUANTA

The infuence of γ-radiation with a dose Dγ = 140 krad on the photoluminescence of Yb-doped GaS single crystals was investigated. Based on the analysis of the experimental results, it is concluded that the doping of the rare-earth element Yb and γ-radiation leads to an increase in the intensity of photoluminescence radiation in GaS.

Ductile behavior and excellent corrosion resistance of Mg-Zn-Yb-Ag metallic glasses

Magnesium-based metal glasses (MMGs) have broad application potential as bio-implant materials because of their disordered atomic structure, fine degradability, low elasticity modulus, and high strength. However, their low plasticity and poor corrosion resistance limit their application. In the present study, Mg-Zn-Yb-Ag metallic glasses were fabricated by injecting into a copper roller. The addition of trace amounts of ytterbium (Yb) and precious metal silver significantly improved the ductility of MMGs under bending and tensile loading. The results show that the amorphous alloy with 4 at% of Yb exhibits optimum specific strength mainly because of high-density coarsening shear bands. Electrochemical experiments, immersion test, and analysis of corrosion products by XPS and EDS after immersion showed that the amorphous alloy with 4 at% of Yb exhibits the greatest corrosion resistance among the four samples because of rare earth (Yb) oxide film. The addition of the appropriate amount of the rare-earth element Yb to amorphous Mg-based alloys can not only remarkably influence the alloy plasticity but also improve the alloy corrosion resistance, thereby increasing the alloy application prospects.

Microstructure and corrosion behavior of as-cast ADC12 alloy with rare earth Yb addition and hot extrusion

The effects of rare earth ytterbium (Yb) addition and hot extrusion on the microstructure and corrosion behavior of as-cast ADC12 were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The experimental results demonstrate that both the Si phase and β-Al5FeSi phase in the alloy with 0.9 wt% Yb have been remarkably refined, and the Al3Yb intermetallic compound has also been obtained. The Si, β-Al5FeSi, and rare earth phases are further refined in the alloy at 0.9 wt% Yb and hot extrusion. The results of the immersion corrosion tests and electrochemical experiments show that the corrosion current density (8.56 µA/cm2) of the alloy with 0.9 wt% Yb addition and hot extrusion is 50.6% lower than the untreated alloy (17.33 µA/cm2), and the polarization resistance (9252 Ω·cm2) was 71.3% higher than the untreated alloy (2654 Ω·cm2). The corrosion in the cathode phase in the micro-battery was refined to varying degrees attributable to the addition of Yb and hot extrusion, where the cathode reaction in the corrosion process caused a decrease of the corrosion rate.

Structural, dielectric, reflection and optical characteristics of the rare-earth (Yb, Er, Dy and Eu) substituted M-phase Li1+x-yNb1-x-3yTix+4yO3 solid solutions

Structural, dielectric, reflection and optical characteristics of 2.5 wt% rare-earth Yb, Er, Dy and Eu substituted Li1+x-yNb1-x-3yTix+4yO3 (x = 0.10,y = 0.00) prepared by solid-state reaction technique have been studied in detail. X-ray powder diffraction demonstrated the hexagonal structure of all the sintered compositions. Scanning electron microscopy showed the formation of spherical grains with high density (relative density > 96%). Relative permittivity ranged from 46.34 to 70.20 and loss tangent varied from 0.417 to 0.022 for sintered specimens in 10 kHz to 1 MHz frequency range. Relative permittivity ranged from 29.29 to 45.84 and loss tangent varied from 0.069 to 0.0361 in 8.2 GHz–18 GHz frequency range. Eu substituted Li1+x-yNb1-x-3yTix+4yO3 exhibited good results having more than 95% microwave reflection with 6.076 GHz bandwidth. Synthesized dielectric materials showed BGYR (blue, green, yellow and red) color emission. Eu substituted Li1+x-yNb1-x-3yTix+4yO3 showed a good photoluminous intensity (IPL = 608) at 628 nm emission wavelength corresponding to red emission.

Effect of rare earth Yb on microstructure and corrosion resistance of ADC12 aluminum alloy

Optical microscopy, scanning electron microscopy, energy dispersive spectrometer, and X-ray diffractometer were used to study the effect of rare earth Yb (0, 0.3, 0.6, 0.9, and 1.2 wt%) on microstructure and corrosion resistance of ADC12 aluminum alloy. The results showed the α-Al, eutectic Si and β-Al5FeSi phase in the alloys with addition of rare earth Yb were obviously refined. The Al3Yb intermetallic compound was also observed with 0.9 wt% Yb addition. The immersion and electrochemical test results showed that the corrosion current density (1.27 μA cm−2) of the 0.9 wt% Yb modified alloy was 84.7% lower than that of matrix (8.302 μA cm−2), corresponding weight loss rate of the alloy shows a minimum value for 46 μg cm−2 day−1. Formation of Al3Yb on the cathode Si hindered the growth of the Si phase, which suppressed the corrosion activity of the cathode region and decreased the rate of micro-galvanic corrosion.

Трехмерная люминесцентная томографическая визуализация биотканей-=SUP=-*-=/SUP=-

AbstractWe propose a method for obtaining a fluorescence tomographic image for visualization and diagnosis of tissues of a living organism. The method is based on the excitation of the luminescence of multicolor upconverting nanoparticles localized in the depth of the biological tissue or a phantom imitating it by IR light. By recording the changes in the shape of the spectrum of the intensity of luminescence radiation from luminescent nanoparticles on the surface of the tissue, it is possible to obtain information about the depth of their occurrence. To implement this approach, upconverting nanoparticles were synthesized on the base of β-NaYF_4 crystal matrix doped with rare-earth elements Yb^3+, Er^3+, and Tm^3+. The luminescence spectra of the produced nanoparticles upon excitation at a wavelength of 980 nm contain three narrow bands with maxima at wavelengths 540, 655, and 800 nm.

Rare earth doping and effective band-convergence in SnTe for improved thermoelectric performance

Thermoelectric performance of SnTe has been found to enhance with isovalent doping of alkaline and transition metal elements where most of these elements have a solubility of less than 13%. We propose a strategy of doping rare earth element Yb to enhance the thermoelectric performance of SnTe. With heavy atomic mass and strong spin-orbit coupling, even the mild doping of Yb (∼5%) is enough to create a degeneracy via band-convergence which enhances the density of states near the Fermi level and improves the overall performance. Our transport data and first-principles calculations corroborate that nearly 5% Yb is an efficient dopant to achieve thermoelectric response which is equivalent to 9% of Mn doping. The results are useful for understanding the environmentally friendly thermoelectric SnTe.

Controllable synthesis of lanthanide Yb3+ and Er3+ co-doped AWO4 (A = Ca, Sr, Ba) micro-structured materials: phase, morphology and up-conversion luminescence enhancement.

Lanthanide ion (Yb3+, Er3+) co-doped AWO4 (A = Ca, Sr, Ba) up-conversion (UC) luminescent materials have been synthesized using a hydrothermal method and characterized by various microstructural and optical techniques. The results indicate that AWO4:Yb3+,Er3+ samples have an identical body-centered tetragonal scheelite structure with different morphologies, including CaWO4:Yb3+,Er3+ microspheres, dumbbell-like SrWO4:Yb3+,Er3+ and bipyramid-like BaWO4:Yb3+,Er3+. These samples exhibit visible emissions via an UC process under near-infrared (NIR) light (980 nm) excitation. Interestingly, the UC luminescence properties of AWO4:Yb3+,Er3+ can be prominently increased after combination with fluorescent carbon dots (CDs) to form CDs@AWO4:Yb3+,Er3+ composites. Compared to the corresponding samples without combination with CDs, the UC emission intensities of CDs@CaWO4:Yb3+,Er3+, CDs@SrWO4:Yb3+,Er3+ and CDs@BaWO4:Yb3+,Er3+ composites increase about three, six and seven fold in the green emission area, and two, three and four fold in the red emission area, respectively. The mechanism of UC luminescence enhancement is probably that the loss of non-radiative transitions from the higher energy levels to the lower excited levels could be effectively reduced through the energy capture by the CD energy levels. The fluorescence enhancement for Yb3+ and Er3+ co-doped AWO4 through combination with CDs provides a simple strategy for the tungstate system and other UC luminescent host systems.

Modulation of magnetic damping constant of Fe2Co films by heavy doping of rare-earth Yb

The effect of rare-earth element Yb doping on modulating the magnetic properties, especially the damping constant, is investigated in a series of amorphous (Fe2Co)(1−x)Ybx thin films by the time-resolved magneto-optical Kerr effect at room temperature. A linear decrease of the saturation magnetization and in-plane uniaxial anisotropy field with the increase of x was observed and explained by the diluted effect of non-magnetic Yb doping. The magnetic damping constant performs a remarkable increase with Yb concentration. X-ray photoelectron spectroscopy reveals partial oxidation of Yb, which has large orbital moment and the associated large spin–orbital coupling (SOC) strength and may be responsible for the increased damping constant in contrast with the expected weak SOC and associated low damping constant of metallic Yb doping.

Ethanol Catalytic Oxidation on Yb Promoted Pd/C in Alkaline Medium

To promote the alcohol catalytic oxidation of Pd/C catalysts, it was implemented that the lanthanide Yb was introduced to the catalyst via the precipitation thermal decomposition and chemical reduction methods. The structure analysis and surface morphology of Pd-Yb/C catalysts were investigated by XRD and SEM. The ethanol electrocatalytic oxidation activity of in alkaline media was studied by cyclic voltammetry. The results show that the performance of ethanol catalytic oxidation on Pd-Yb/C electrode is better than that on the Pd/C electrode. The introduction of Yb can promote Pd/C catalytic oxidation alcohol and its poisoning tolerance ability.

Iceland is not a magmatic analog for the Hadean: Evidence from the zircon record

Tangible evidence of Earth's earliest (Hadean; >4.0 Ga) crust, and the processes and materials that contributed to its formation, exists almost entirely in a record of detrital zircon from Jack Hills, Western Australia, and a few other locations. Iceland, with its thick, juvenile, basaltic crust and relatively abundant silicic rocks, is considered a potential modern analog for the Hadean magmatic environment where >4 Ga zircon formed. We present the first extensive dataset for Icelandic zircon, with trace element and oxygen isotope compositions from samples that span the island's history and full range of tectonic settings. This statistically robust zircon-based comparison between Iceland and the early Earth reveals distinctions in chemistry that suggest fundamental differences in magmatic environments. Whereas the δ18O signature of Hadean zircons generally exceed that of zircons equilibrated with mantle-derived magma (85%≥5.3‰; median 6‰), almost all Icelandic zircons are characterized by a “light” oxygen signature (98%≤5.3‰; median 3‰). Deviations from “juvenile” oxygen values indicate that many Hadean zircons and almost all Icelandic zircons grew from magmas with substantial contributions from materials that had interacted with surface waters. In the Hadean case, the interaction occurred at low temperatures, while in Iceland, it was a high-temperature interaction. Icelandic and Hadean zircons are also distinct in their Ti concentrations (Icelandic median concentration 12 ppm, Hadean median 5 ppm). Titanium in zircon correlates positively with temperature of crystallization, and this difference in median Ti concentration suggests a temperature difference of at least 50 °C. Other differences in trace elements compositions are consistent with the interpretation that Icelandic and Hadean zircons grew in magmas with very different origins and histories (e.g., the heavy rare earth element Yb is almost an order of magnitude higher in Icelandic zircon). A comparison with elemental data for Phanerozoic zircon from different environments demonstrates that the Hadean population is unusually depleted in Ti, but otherwise similar to zircons from continental arc settings. Zircons from Iceland, and from modern evolving rift environments where oceanic lithosphere and upwelling asthenosphere are replacing continental lithosphere, are compositionally intermediate between mid-ocean ridge and continental arc zircon populations. The elemental distinctions are consistent with fractionation of zircon-bearing magmas under hotter and drier conditions in Icelandic, mid-ocean ridge, and evolving rift environments and cooler and wetter conditions in arc and, especially, Hadean environments.

Chemical effects of Lγ4 emission spectra

An overview of the chemical effects of the Lγ4 (L1O2,3) emission of Ce, Sm, Eu, and Yb is reported. The Lγ4 emission spectra differ significantly depending on the chemical environment of the lanthanides. The emission from the early lanthanide Ce is ligand-dependent, whereas the emission from the middle lanthanides, Sm and Eu, is valence-dependent with chemical shifts of 4–5eV. The emission from the late lanthanide Yb, which exhibits Lγ4 and Lγ4' bands, depends on both the valency and the coordination environment. Thus, Lγ4 emission is a potentially useful probe that can be used to evaluate the chemical states of lanthanides, in particular, the oxidation numbers of middle to late lanthanides in mixed-valence compounds.

Properties enhancement of SnAgCu solders containing rare earth Yb

In order to enhance the properties of SnAgCu lead-free solders in microelectronic packaging, various contents of rare earth Yb were incorporated into the alloys. Results indicated that the addition of Yb can improve the wettability, tensile strength, thermal fatigue behavior of lead-free alloys. The lead-free solder with 0.05%Yb addition exhibited the best comprehensive properties as compared to the alloys with other Yb weight fractions. And found that after soldering, the initial interfacial IMC thickness of SnAgCuYb solder joint was smaller than that of SnAgCu solder joints, and this signified that the addition of Yb was effective in retarding the growth of the IMC layer. In addition, the Yb can refine the microstructures of SnAgCu solder, excessive Yb added can form bulk Sn–Yb phase and deteriorate the properties.