Yttrium In Solution Research Articles

Heat Capacity and Features of the Phonon Spectrum of Single Crystals of Solid Solutions of Yttrium–Lutetium Aluminum Garnets

The temperature dependences of the heat capacity were measured and the general patterns of the formation of the phonon spectrum of single crystals of solid solutions of yttrium-lutetium aluminum garnets Y3 – xLuxAl5O12 at 0 ≤ x ≤ 3 were investigated in the temperature range from 1.9 to 220 K. According to the data obtained at temperatures below 10 K, the Debye temperatures were calculated. The features of the phonon spectrum in the intermediate temperature range are interpreted as a superposition of optical modes for yttrium and lutetium garnets. It is shown that the low heat capacity values due to the contribution of acoustic phonons for Y2.25Lu0.75Al5O12 correlate with anomalies in the concentration dependences of the phonon transport, the absorption of acoustic waves, and the shape of the aluminum NMR line.

Defining the optimal conditions using FFNNs and NARX neural networks for modelling the extraction of Sc from aqueous solution by Cryptand-2.2.1 and Cryptand-2.1.1

The main aim of this study is to figure out how well cryptand-2.2.1 (C 2.2.1) and cryptand-2.1.1 (C 2.1.1) macrocyclic compounds (MCs) work as novel extractants for scandium (Sc) by using an artificial neural network (ANN) models in MATLAB software. Moreover, C2.2.1 and C2.1.1 have never been evaluated to recover Sc. The independent variables impacting the extraction process (concentration of MC, concentration of Sc, pH, and time), and a nonlinear autoregressive network with exogenous input (NARX) and feed-forward neural network (FFNN) models were used to estimate their optimum values. The greatest obstacle in the selective recovery process of the REEs is the similarity in their physicochemical properties, specifically their ionic radius. The recovery of Sc from the aqueous solution was experimentally evaluated, then the non-linear relationship between those parameters was predictively modeled using (NARX) and (FFNN). To confirm the extraction and stripping efficiency, an atomic absorption spectrophotometer (AAS) was employed. The results of the extraction investigations show that, for the best conditions of 0.008 mol/L MC concentration, 10 min of contact time, pH 2 of the aqueous solution, and 75 mg/L Sc initial concentration, respectively, the C 2.1.1 and C 2.2.1 extractants may reach 99 % of Sc extraction efficiency. Sc was recovered from a multi-element solution of scandium (Sc), yttrium (Y), and lanthanum (La) under these circumstances. Whereas, at a concentration of 0.3 mol/L of hydrochloric acid, the extraction of Sc was 99 %, as opposed to Y 10 % and La 7 %. The Levenberg-Marquardt training algorithm had the best training performance with an mean-squared-error, MSE, of 5.232x10−6 and 6.1387x10−5 for C 2.2.1 and C 2.1.1 respectively. The optimized FFNN architecture of 4-10-1 was constructed for modeling recovery of Sc. The extraction process was well modeled by the FFNN with an R2 of 0.999 for the two MC, indicating that the observed Sc recovery efficiency consistent with the predicted one.

Diverse Coordination Chemistry of the Whole Series Rare-Earth L-Lactates: Synthetic Features, Crystal Structure, and Application in Chemical Solution Deposition of Ln2O3 Thin Films.

Rare-earth (RE, Ln) carboxylates are widely studied as precursors of RE oxide-based nanomaterials; however, no systematic studies of RE L-lactates (HLact = 2-hydroxypropanoic acid) have been reported to date. In the present work, a profound structural investigation of RE L-lactates is carried out. A family of RE lactate complexes of the general formula LnLact3∙nH2O (Ln = La, Ce-Nd, Sm-Lu, Y; n = 2-3) are synthesized and characterized by CHN, TGA, and FTIR as well as by powder and single-crystal XRD methods.The existence of four novel structural types (1-Ln-4-Ln) is revealed. Compounds of the 1-Ln type (Ln = La, Ce, Pr) exhibit a chain polymeric structure, whereas 2-Ln-4-Ln compounds are molecular crystals consisting of dimeric (2-Ln; Ln = La, Ce-Nd) or monomeric (3-Ln-Ln = Sm-Lu, Y; 4-Ln-Ln = Sm-Gd, Y) species. The crystal structures of 1-Ln-4-Ln compounds are discussed in terms of their coordination geometry and supramolecular arrangement. Solutions of yttrium and lanthanum lactates with diethylenetriamine are applied for the chemical deposition of Y2O3 and La2O3 thin films.

STUDIES OF HYDROCHLORIC ACID DECOMPOSITION OF CLAY SLURRIES OF SILICEOUS-TITANIUM ORES

The chemical and mineral compositions of gray-colored and red-colored slurries formed during the disintegration of silicon-titanium ores of the Pyzhemskoye deposit are considered, and the results of a study on their hydrochloric acid leaching of 20% HCl in the temperature range of 40-200°С are presented. It is shown that an increase in the leaching temperature leads to an increase in the degree of opening of sludge, which is associated with the decomposition of a number of mineral phases. At temperatures of 40-100°С, the decomposition of siderite and goethite proceeds. The decomposition of clay minerals develops at a temperature of 90° C and above. The process is accompanied by the release of gel-like SiO2. Under autoclave conditions, the decomposition of pseudorutyl, as well as monazite and xenotime occurs simultaneously with the transfer to a solution of cerium, neodymium and yttrium. Complete decomposition of REM minerals is achieved at a temperature of 180°С. The non-decomposable solid residue is represented by rutile, quartz, amorphous SiO2 and zircon.

The Electrophoretic Deposition of Nanopowders Based on Yttrium Oxide for Bulk Ceramics Fabrication

In the present work, a study was carried out to investigate the key factors that determine the uniformity, mass, thickness, and density of compacts obtained from nanopowders of solid solutions of yttrium and lanthanum oxides ((LaxY1−x)2O3) with the help of the electrophoretic deposition (EPD). Nanopowders were obtained by laser ablation of a mixture of powders of yttrium oxide and lanthanum oxide in air. The implemented mechanisms of the EPD and factors of stability of alcohol suspensions are analyzed. It has been shown that acetylacetone with a concentration of 1 mg/m2 can be used as a dispersant for stabilization of isopropanol suspensions of the nanoparticles during the EPD. It was shown that the maximum density of dry compacts with a thickness of 2.4 mm reaches 37% of theoretical when EPD is performed in vertical direction from a suspension of nanopowders with addition of acetylacetone.

Analysis of the Adsorption-Release Isotherms of Pentaethylenehexamine-Modified Sorbents for Rare Earth Elements (Y, Nd, La).

Waste from electrical and electronic equipment (WEEE) is constantly increasing in quantity and becoming more and more heterogeneous as technology is rapidly advancing. The negative impacts it has on human and environment safety, and its richness in valuable rare earth elements (REEs), are accelerating the necessity of innovative methods for recycling and recovery processes. The aim of this work is to comprehend the adsorption and release mechanisms of two different solid sorbents, activated carbon (AC) and its pentaethylenehexamine (PEHA)-modified derivative (MAC), which were deemed adequate for the treatment of REEs deriving from WEEE. Experimental data from adsorption and release tests, performed on synthetic mono-ionic solutions of yttrium, neodymium, and lanthanum, were modelled via linear regression to understand the better prediction between the Langmuir and the Freundlich isotherms for each REE-sorbent couple. The parameters extrapolated from the mathematical modelling were useful to gain an a priori knowledge of the REEs-sorbents interactions. Intraparticle diffusion was the main adsorption mechanism for AC. PEHA contributed to adsorption by means of coordination on amino groups. Release was based on protons fostering both a cation exchange mechanism and protonation. The investigated materials confirmed their potential suitability to be employed in real processes on WEEE at the industrial level.

Theoretical investigation on yttrium clustering in tungsten grain boundary region and strengthening effect

We have systematically investigated the solution and aggregation behaviors of yttrium (Y) on symmetrically inclined tungsten (W) grain boundary (GB) Σ5(310)/[001] by first-principles simulation. It is found that the most stable site for Y is located on the GB plane, and the solution energy of the Y substitutional site increases with increasing the distance from the GB plane. The charge redistribution of Y atoms is positively correlated with the solution energy, i.e., the deviation of the electrons of Y atoms is beneficial to its solution in the W–GB system. Further, the segregation of multiple Y atoms in the W–GB is clearly observed, where the Y atoms preferentially occupy the GB plane substitutional sites. The alloying Y atoms at the GB plane sites can effectively strengthen the GB when the concentration is less than 3.367%. The stronger binding energy of W–Y than the binding energy of W–W in the GB region is the main factor for the strengthening of the GB.

ANALYSIS OF SPECTRAL AND KINETIC CHARACTERISTICS OF CATHODOLUMINESCENCE OF Y2O3:Eu THIN FILMS AS A RED COMPONENT OF FULL-COLOR HIGH-RESOLUTION FLUORESCENT DISPLAYS

The spectra and kinetics of the rising and decay of cathodoluminescence (CL) of thin Y 2 O 3 :Eu films obtained by the method of RF-magnetron sputtering are studied. Based on the shape of the CL spectra at different energies and excitation current densities, the possibility of the formation of irregular solutions of yttrium and europium oxide and the features of the structure of surface and bulk layers are shown. The dependence of the CL intensity on the energy of the exciting electrons and the current density of the electron irradiation has been investigated. The CL decay time constant for the 612 nm luminescence is determined, the value of which is in the range (1.8 – 4.1) ms. It is shown that this quantity is a complex function of the type of film deposition atmosphere, the concentration of the activator, and the duration of the exciting pulses. The features of CL rising are investigated and it is proposed to analyze the structural perfection of Y 2 O 3 :Eu thin films based on the delay in CL rising. Key words : yttrium oxide, cathodoluminescence, thin films.

Laser desorption/ionization time-of-flight mass spectrometry of yttrium(III) chloride

Due to the increased use of yttrium in agriculture and industry, there is a growing interest in the impact of yttrium on the environment and human health. Developing novel procedures to detect and quantify species of yttrium represents an important task. In this work, we apply laser desorption/ionization-mass spectrometry (LDI-MS) to detect cluster ions of the solution of yttrium(III) chloride (YCl3) at different pH values. The density functional theory (DFT) calculations were used to reveal the energetically most favored structures of the anions and cations chosen from the LDI-MS results. Examination of the positive and negative mode LDI mass spectra of YCl3 showed the presence of the heterogeneous mononuclear and polynuclear clusters, such as [YCl(OH) (H2O)3][Formula: see text], [Y2(H2O)][Formula: see text], [Y4H2(H2O)4][Formula: see text], and [Y5O4H3][Formula: see text] (at pH 2 and 5) and [Y2Cl2(H2O)2][Formula: see text], [Y2O5(HCl)(OH)][Formula: see text], and [Y3OH3(OH)2(H2O)][Formula: see text] (at pH 2, 5, and 10). The variation in the pH solution of YCl3 slightly affects the LDI mass spectrum of these yttrium clusters. It has only been noticed that the [Y4H2(H2O)4][Formula: see text] cluster ions were not detected at pH 10. These results can become a guide in the detection of yttrium chloride by LDI-MS in real samples in different fields (ecological, food, and human).

Синтез оптической Nd:(Y,Gd)2O3-керамики и исследование ее спектроскопических характеристик

Fabrication of optical ceramics based on solid solution of yttrium and gadolinium sesquioxides activated by Nd3+ ions was reported. Nanopowder of Nd0.08(Y0.496Gd0.496)2O3 synthesized by laser ablation method was used as raw material. It was determined that laser-ablated nanoparticles initially have monoclinic phase transformation of which into cubic phase is started at the temperature of 1100 °C and fully completed at 1300 °C. It was found that the best transparency of samples (79.9% at the wavelength of 1060 nm) and lowest content of scattering centers of 2.7 ppm are reached by vacuum sintering of nanopowder previously calcined at 1000 °C for 3 h. A blue-shift of Nd3+ emission bands in (Y,Gd)2O3 matrix with respect to Y2O3 was observed as a result of measuring of photoluminescence spectrum. Broadening of emission bands and their partial overlap was determined suggesting the alteration of local environment of neodymium which embeds into positions of yttrium as well as gadolinium.

A review on determination of 90Sr from alkaline waters using precipitation of Ca(OH)2 and Ba(Ra)SO4

Since the Chernobyl accident (1989) and the Fukushima Daiichi Nuclear Power Plant accident in 2011, concern about the contamination of 90Sr in the environment has increased considerably. It is important for public safety to monitor 90Sr in aquatic environments due to the radiotoxic of its biochemical similarities with calcium in living organisms. Several techniques for the separation of strontium from matrices have been reported such as solvent extraction, liquid membrane extraction, ion-exchange, and extraction chromatography using Sr-Resin. This review provided a summary on literature works to develop efficiency radiochemical separation for removing 90Sr from waters. Radiometric method normally requires a long time and complete separation of Sr from the matrix and other radionuclides. One of simple method based on Ca(OH)2 precipitation in alkaline solution and purification of Yttrium using Ba(Ra)SO4 precipitate was applied to the separation of Sr from seawater and underground water sample. This review is a mini-report for determination of 90Sr removal from contaminated waters.

Development of the Certified Reference Materials in the field of physical and chemical analysis. Reference Materials of the composition of aqueous solutions of yttrium and scandium ions

In this work is described to study on rare-earth elements scandium and yttrium were, the development of certified reference materials of aqueous solutions of yttrium and scandium ions.

Aerosol Synthesis of Highly Dispersed Y3Al5O12:Ce3+ Phosphor with Intense Photoluminescence

A simple method of pyrolysis of an aerosol solution of yttrium, aluminum, and cerium nitrates with the addition of urea or citric acid, followed by brief annealing, is developed to obtain a highly dispersed aluminum–yttrium garnet powder that demonstrates intense photoluminescence in the visible light region. Characterization of the synthesized samples (photoluminescence spectra, X-ray diffraction analysis, Raman spectra) showed that intense photoluminescence is achieved only in a narrow window of process conditions, namely, the concentration of nitrate solution and the concentration of citric acid or urea. The photoluminescence intensity increases upon annealing synchronously with an increase in the crystallite size, which, along with the optimal cerium concentration (~0.5 at %), is a determining factor for obtaining high-quality samples. The synthesized powders had intense photoluminescence and high optical perfection, as evidenced by the observation of whispering gallery modes.

Microstructure and Thermal-protective Property of CPED Coating with ZrO2 Nanoparticles Addition on Al-12Si Alloy

A novel thermal-protective coating has been successfully prepared by CPED process on a cast Al-12%Si alloy with the addition of ZrO2 nano-particles in the electrolyte. The microstructures and phase composition of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. With ZrO2 nanoparticles addition, the cathode plasma discharge on the coating surface is more obvious than that without ZrO2 nanoparticles addition, the coating is more uniform and compact, and the thickness of the coating increases. Furthermore, the content of Zr and Y elements increases and the degree of crystallization of the coating is more complete. The formation of the solid solution of yttrium stabilized zirconia is promoted by cathode plasma discharge. In addition, the thermal insulation temperature increases as ZrO2 nano-particles are added to the electrolyte. After 1 000 cycles of thermal shock, there was no cracking in the coating surface layer, which indicated that the CPED coating with ZrO2 nanoparticles addition possessed a good thermal shock resistance.

Аэрозольный синтез высокодисперсного люминофора Y-=SUB=-3-=/SUB=-Al-=SUB=-5-=/SUB=-O-=SUB=-12-=/SUB=- : Ce-=SUP=-3+-=/SUP=- с интенсивной фотолюминесценцией

AbstractA simple method of pyrolysis of an aerosol solution of yttrium, aluminum, and cerium nitrates with the addition of urea or citric acid, followed by brief annealing, is developed to obtain a highly dispersed aluminum–yttrium garnet powder that demonstrates intense photoluminescence in the visible light region. Characterization of the synthesized samples (photoluminescence spectra, X-ray diffraction analysis, Raman spectra) showed that intense photoluminescence is achieved only in a narrow window of process conditions, namely, the concentration of nitrate solution and the concentration of citric acid or urea. The photoluminescence intensity increases upon annealing synchronously with an increase in the crystallite size, which, along with the optimal cerium concentration (~0.5 at %), is a determining factor for obtaining high-quality samples. The synthesized powders had intense photoluminescence and high optical perfection, as evidenced by the observation of whispering gallery modes.

Spectroscopic and laser characteristics of ceramics based on Yb3+-doped Lu2O3–Y2O3 solid solution

We report on quasi-cw lasing at a wavelength of 1031 nm with a maximum power of 8 W and a slope efficiency of 32.3 % achieved in a thin-disk ceramic element based on ytterbium-doped solid solution of yttrium and lutetium sesquioxides. A sample of Yb : (Lu, Y)2O3 ceramics was fabricated by solid-state sintering of nanosized particles of a predetermined composition synthesised by laser ablation. The study of the spectral and luminescent characteristics of the obtained ceramics shows that partial substitution of Y3+ cations by Lu3+ cations broadens the absorption, luminescence, and laser spectra and shifts their peaks with respect to those of Yb:Y2O3 ceramics.

Recovery of yttrium and neodymium from copper pregnant leach solutions by solvent extraction

The solvent extraction of yttrium and neodymium from copper pregnant leach solutions (PLS) using Primene JM-T, a primary aliphatic amine, has been studied. Effect of contact time, pH, sulfate concentration, and extractant concentration were investigated using synthetic and actual PLS systems. Standard experimental conditions were 5 min contact time, pH ~ 2.5, 10 % v/v Primene JM-T concentration, and 1:1 O:A phase ratio. Distribution isotherms were constructed for the pure systems and for actual copper leach solutions. Synthetic solutions contained 100 ppm Y and ~75 ppm Nd. Copper PLS contained 14.9 ppm Y and 2.1 ppm Y. Results showed that complete extraction of both yttrium and neodymium occurred within 5 min and at pH values greater than 1. It was also found that sulfate concentration does not inhibit extraction at any concentration. Using synthetic solutions of yttrium and neodymium, it was found that the reaction stoichiometry requires 2 moles of Primene JM-T per mole of metal extracted. This suggests that a both bi-sulfate and tri-sulfate complexes are being extraction. For the copper bearing PLS, 3 moles of Primene JM-T were required per mole of metal extracted. This support the tri-sulfate complex as being the predominate species being extracted.

Structure and Cathodoluminescent Properties of Y2O3:Eu Thin Films at Different Activator Concentrations

The surface structure and cathodoluminescence (CL) spectra of thin films of Y2O3:Eu obtained by HF ion plasma sputtering were investigated by varying the activator concentration in the range of 1.0–7.5 mole%. The possibility of creating irregular solutions of yttrium and europium oxides and the structural features of the small and large crystallites that form the Y2O3:Eu film were demonstrated on the basis of the shape of the CL spectra at different activator concentrations. The critical distance for interaction between the Eu3+ ions at nodes with C2 and C3i point symmetry was estimated, and a mechanism of energy migration between these centers was proposed.

Influence of Obtainment Conditions and Excitation Into Spectral and Kinetic Characteristics of Cathodoluminescence in Y2O3:Eu Thin Films

The spectra and kinetics of the rise and decay of the cathodoluminescence (CL) of thin films of Y2O3:Eu obtained by RF-magnetron sputtering were investigated. Based on the shape of the CL spectra at different excitation energies, it showed the possibility of creating irregular solutions of yttrium and europium oxides and the structural features of the surface and bulk layers. The time constant for the decay CL for 612 nm emission was determined and the value of which is within the range (1.8 - 4.1) ms. This value is a complex function of the type of film deposition atmosphere, the activator concentration, and the duration of the exciting pulses was shown. The features of the risen CL and the proposal based on the delayed rise CL analyze structural perfection of Y2O3:Eu thin films.

Atomically ordered solute segregation behaviour in an oxide grain boundary.

Grain boundary segregation is a critical issue in materials science because it determines the properties of individual grain boundaries and thus governs the macroscopic properties of materials. Recent progress in electron microscopy has greatly improved our understanding of grain boundary segregation phenomena down to atomistic dimensions, but solute segregation is still extremely challenging to experimentally identify at the atomic scale. Here, we report direct observations of atomic-scale yttrium solute segregation behaviours in an yttria-stabilized-zirconia grain boundary using atomic-resolution energy-dispersive X-ray spectroscopy analysis. We found that yttrium solute atoms preferentially segregate to specific atomic sites at the core of the grain boundary, forming a unique chemically-ordered structure across the grain boundary.