Yttrium Atoms Research Articles

Effects of yttrium doping on helium behavior in zirconium hydride films

The zirconium hydride alloy films with different yttrium concentration were prepared by magnetron sputtering and studied using ion beam analysis (IBA), X-ray diffraction (XRD), thermal desorption spectrometry (TDS), positron annihilation spectroscopy (PAS) and nanoindentation. It was found that the yttrium atom, which is originally insoluble in zirconium metal, can largely dissolve in the zirconium hydride matrix through the introduction of hydrogen. The helium thermal desorption experiment shows that as the doped amount of yttrium atoms increases, a large number of helium atoms will be released in the form of helium bubbles at the grain boundaries in the matrix at ca. 900K. Combined with XRD results, it is concluded that as the yttrium atoms are introduced, more grain boundaries will form in the zirconium hydride matrix. These grain boundaries act as crystal defects, which have a strong trapping effect on helium atoms, causing a large number of helium bubbles to aggregate at the grain boundaries in the matrix. In addition, it is noteworthy that yttrium doping can increase the hardness and elastic modulus of zirconium hydride.

New insights into the mechanism of yttrium changing high-temperature oxide growth of Fe-13Cr–6Al–2Mo–0.5Nb alloy for fuel cladding

The oxidation behavior and microstructure evolution of Fe–13Cr–6Al–2Mo–0.5Nb alloys with various yttrium contents ranging from 0 to 0.23 wt.% have been investigated at 1200 °C for 4 h in steam environment. The oxide weight gain decreased with minor addition of yttrium, but this tendency was lost with excess addition. The grain boundary migration was hindered due to high binding energy of yttrium atom and vacancy. The combination of yttrium with vacancies and a large number of fine Laves phases at grain boundaries suppressed the outward diffusion of Al3+, resulting in the change of oxide growth mechanism and oxide scale adhesion.

Encapsulated Yttrium Atoms in Carbon Cages: Spheres or Tubes?

Yttrium clusters entrapped within smaller C60-C90 fullerene cages are well known. However, there is minimal literature for yttrium atoms entrapped in the larger carbon cages. To avoid the separation nightmare that is soot extract, we simplify the mixture by chemically removing co-eluting contaminants. Herein, we describe a selective chemical reaction that effectively serves as a pre-cleanup step prior to introducing HPLC fraction collection. In Stage 2, the enriched Y-based carbon species are readily isolated chromatographically. In this presentation, we describe our two-step purification of yttrium atoms entrapped in the larger carbon cages, (e.g., C92-C102). Subsequent characterization, such as UV-Vis, of these yttrium metallofullerenes are underway.

Imaging reaction dynamics of Y+SO2

The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging, crossed molecular beam and laser-ablation method. The product YO was detected via multiphoton ionization at various wavelengths in the region of 482–615 nm. The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution. The forward scattering signal is stronger than its backward distribution. This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period. The formation of complex suggests that electron transfer occurs in the oxidation reaction.

Effect of the Rare Earth Element Yttrium on the Structure and Properties of Boron-Containing High-Entropy Alloy

The effects of rare earth yttrium with 0.1, 0.2 and 0.5 atomic ratios on the microstructure and properties of FeCoNi1.5CuB high-entropy alloy were investigated. The results show that the lattice distortion of the matrix alloy is increased after yttrium addition. There are three characteristic zones: the bulk trivalent boride phase zone, basement zone and yttrium-rich precipitate zone. When the yttrium atom ratio is > 0.2, the nanoscale YB6 particles disperse uniformly in the yttrium-rich zone, which can improve the strength of the alloy. As for the mechanical properties, the FeCoNi1.5CuBY0.2 alloy has the highest strength. The corresponding compressive strength, yield strength and maximum compression ratio have been increased by 19.9%, 75.4% and 37%, respectively, compared with those of FeCoNi1.5CuB alloy. This is attributed to the solid solution, grain refinement and dispersion strengthening in the presence of yttrium addition.

Electronic Structure and Optical Properties of YAlN: A First‐Principles Study

To reveal the intrinsic relationship between the electronic structure and optical properties of YxAl1−xN alloys, a comparative first‐principles study for pure AlN and YxAl1−xN alloys is conducted. In light of the density functional theory, the arrangement of yttrium (Y) atoms in the AlN supercell is first investigated, which demonstrates that the structure of Y atoms distributed locally along the c‐axis tends to be energetically favorable, compared with the structures of Y atoms lying on the same ab plane. The lattice parameters, bandgap, density of states, and optical constants are also calculated with varied Y concentration x. The results indicate that the lattice parameters increase with the ascending x, which demonstrates the distortion of the crystal structure. Moreover, the bandgaps of YxAl1−xN are found to be affected by the arrangement of Y atoms but generally with the same trend to become narrowed by the increase in x, respectively. The optical properties of YxAl1−xN alloy are adjustable by the Y concentration x in the low energy regime and correspond to the variation in the bandgaps. The theoretical results are likewise compared with the previously reported experimental data.

Cathodoluminescence properties of monoclinic phased reddish-orange emitting BaY2(MoO4)4:Eu3+ phosphor

A series of Eu3+ activated BaY2(MoO4)4 reddish-orange emitting phosphors was successfully synthesized by changing the doping concentrations of Eu3+ ions using a solid-state reaction route. All the reflections obtained in the powder X-ray diffraction analysis signposted that the as-prepared phosphors belonged to the monoclinic phase with the C2/c space group. Narrow scan X-ray photoelectron spectroscopy analysis suggested that the molybdenum ions were connected tetrahedrally to oxygen with its maximum 6+ valance state and yttrium atoms with 3+ state in the BaY2(MoO4)4:Eu3+ material. The influence of doping concentration of Eu3+ ions on the cathodoluminescence (CL) properties of BaY2(MoO4)4 was explored with respect to various accelerating voltages and filament currents. The penetration depth of the electrons into the phosphors has been estimated as a function of accelerating voltage. The phosphor showed no saturation current or saturation voltage in the ranges that were explored. The CL spectra revealed that reddish-orange emission was witnessed when the phosphor material was stimulated under e− beam excitation due to the 5D0→7F2 transition of the Eu3+ ions. The as-prepared phosphor material exhibited intense and strong CL emission lines with better International Commission on Illumination (CIE) chromaticity coordinates and higher colour purity and can be considered to be utilize in field emission display device applications.

Structural Phase State of Surface Alloyed Y2O3 Silumin After Electron beam Processing

The structure, phase composition and tribological properties of surface layers of hypoeutectic silumin after the complex processing including the electroexplosion alloying with the yttrium oxide powder in different regimes and the subsequent electron beam processing have been analyzed by the methods of modern physical material science. With respect to the initial silumin the ≈20-fold increase in the wear resistance and ≈1.5-fold decrease in the friction coefficient have been detected. The complex processing is accompanied by the formation of the multiphase submicro—nanocrystalline layer up to 80 μm in thickness enriched by yttrium and oxygen atoms responsible for the multiple increase in the wear resistance. At the complex processing according to the first regime of electroexplosion alloying (EEA) (Y2O3 powder mass—0.0589 g, discharge voltage—2.8 kV) with the subsequent electron beam irradiation, the major phase of the modified layer is the solid solution based on Al (≈71.2 mass %), the remaining phases are SiO2, YAlO3, YSi2. The 1.5-fold increase in the mass of Y2O3 powder at EEA and 1.1-fold decrease in the discharge voltage is accompanied by the increase in the quantity of phases, the significant (more than 2.5-fold) decrease in the content of the solid solution based on Al, the ≈2.2-fold increase in the content of silicon oxide, the presence of yttrium oxide and metallic yttrium.

Yttrium doped graphene oxide as a new adsorbent for H2O, CO, and ethylene molecules: Dispersion-corrected DFT calculations

A Grimme dispersion-corrected density functional theory (DFT-D) calculations are performed to explore the electronic structures and adsorption behaviors of graphene oxide (GO) and Yttrium doped graphene oxide (Y doped GO) toward the adsorption of H2O, CO, and C2H4 molecules. The HOMO and LUMO spatial distributions, the electrostatic potential charges, and the field that corresponds to the electrostatic potential are evaluated to understand the effect of the Yttrium doping on the electronic properties of the pristine graphene oxide. Calculated molecular and thermodynamic parameters indicate that the electronic structure of GO is obviously affected by the presence of yttrium atom. It can be seen that the adsorption energies of H2O, CO, and C2H4 molecules adsorption increase from 69.5, 17.4 and 34.7 kJ/mol over the pristine GO to 133.1, 182.4 and 214.2 kJ/mol for the Yttrium doped GO. We believe that the obtained results will provide beneficial insights for experimental research about the potential application of metal-doped graphene oxides as nanoscale adsorbents for water, carbon monoxide, and ethylene molecules.

Insight in the properties of WO3|Y: A first-principle study

In this paper, the properties of WO3|Y when yttrium atoms are adsorbed on the surface of WO3 are studied systematically using first-principles calculations. The most stable WO3(0 0 1) surface configuration (W-O terminal surface) was obtained by calculating the surface energy of the clean surface model. By calculating the adsorption energy (Eads), the most stable adsorption site (S1) was obtained, which has the most negative adsorption energy (−5.58 eV). When one yttrium atom is adsorbed on the most stable adsorption site, the work function (Ф) of the system is reduced from 4.26 to 3.26 eV. The WO3(0 0 1) is found to be an n-type semiconductor with a Fermi level of −0.77 eV by analyzing the energy band structure and density of states. When one Y atom is adsorbed at the S1 site, the Fermi level rises to 0.20 eV, and the band gap width is reduced from 0.33 to 0.14 eV. This finding indicates that WO3(0 0 1) is still an n-type semiconductor, but with a considerably increased absorption range of light.

Enhanced creep resistance of Y-bearing 9Cr ferritic/martensitic steel via vacuum casting technique

9Cr ferritic/martensitic (F/M) steels with 0 and 0.3wt.% yttrium (Y) addition were fabricated via vacuum casting technique and were creep tested at 650°C and 120MPa. The creep property of 9Cr F/M steel was improved by the addition of yttrium. Even though the initial creep rates of 9Cr-0Y and 9Cr-0.3Y were almost the same, the creep rupture life of 9Cr-0.3Y specimen was extended about 2˜3 times with the longer steady state creep stage and the lower minimum creep rate than 9Cr-0Y specimen. The coarsening of grains and martensitic laths occurred during creep, and M23C6 carbides, MX/M2X-type carbonitrides and Fe2W/Mo Laves phase were identified along the boundary in both specimens. For 9Cr-0.3Y, the nano-sized oxide clusters were formed during creep, because of the diffusion and local segregation of the dissolved yttrium and oxygen atoms at high temperature and with the promotion of creep stress. The softening of microstructure recovery is compensated by the dispersion strengthening of nano-particles and the balance of them was the reason of longer steady state creep stage of the creep curves.

Atomic structure of Ni-Nb-Y amorphous alloys and water-surface adsorption characteristics

Amorphous alloys are a unique class of materials, characterized by their lack of long-range structural ordering while retaining short range chemical ordering. The disordered surface structure of amorphous alloys facilitates a high density of uncoordinated sites, with unique surface chemistries and bond lengths that can render them highly electrocatalytically active. The Ni-Nb-Y system possesses the ability to phase separate into two amorphous phases, amorphous Ni60Nb40 and amorphous Ni57Y43. In this work the atomic structures of amorphous Ni60Nb40 and Ni57Y43 were derived and the binding mechanism of water on their respective surfaces was simulated using computational methods. The Ni60Nb40 amorphous structure was found to be dominated by disordered and pristine nickel centred icosahedral polyhedra, with the most abundant nickel centred Voronoi polyhedra being: 〈0,2,8,2〉, 〈0,3,6,4〉, 〈0,0,12,0〉 and 〈0,1,10,2〉. The Ni57Y43 amorphous structure was found to be very disordered, with only the nickel centred 〈0,3,6,0〉 Voronoi polyhedra occurring with an abundance greater than 10%. It was found that water binds to the surface of the Ni60Nb40 through the interaction of the oxygen of an intact water molecule with a surface niobium atom through a predominately ionic interaction. On the other hand, water dissociated upon adsorption into a hydroxide ion and lone hydrogen atom on the Ni57Y43 surface, over roughly three quarters of its area while it remained intact for the other quarter. It was found that the hydroxide ion binds preferentially to surface yttrium sites, while the lone hydrogen had a very high surface mobility and preferred to bind to nickel sites. The strong hybridization of the yttrium atoms with the hydroxide ion likely contributes to the greater electrocatalytic activity of the Ni57Y43 alloy in comparison to the Ni60Nb40 alloy as reported in experiments.

Modification of surface layer of hypoeutectic silumin by electroexplosion alloying followed by electron beam processing

The analysis of structure, phase composition and tribological properties of surface layers of hypoeutectic silumin after complex treatment including the electroexplosion alloying by yttrium oxide powder in different modes and subsequent electron beam processing was done by the methods of modern physical material science. The complex treatment is accompanied by the formation of multi–phase submicro – nanocrystalline layer up to 80 μm thick enriched by yttrium atoms and being responsible for the increase in wear resistance. It is shown that Y atom concentration in the modified layer depends on electroexplosion alloying (EEA) mode. The distribution of Y atoms in the layer depends on the mode of EEA as well.

Effects of yttrium on microstructure and mechanical properties of a directionally solidified single crystal superalloy

Reactive elements such as yttrium are known to have beneficial effects on oxidation resistance of high-temperature materials. This paper focuses on the effects of yttrium on a single crystal nickel-based superalloy. The evolution of microstructure and mechanical properties are analyzed by comparing the alloys with different concentration of yttrium. The results show that most of yttrium atoms are solved at the roots of secondary dendrite arms as during directional solidification. After a solid solution heat treatment (1300 °C), some eutectic precipitates with N17Y2 are produced in the interdendritic areas through a eutectic reaction (L→(Ni)+Ni17Y2). A small amount of yttrium addition will leads a rapid decrease of stress rupture life. However, the tensile strength shows an obviously drop when yttrium is added into the alloy, but turns to be enhanced when concentration of yttrium gets higher.

Effect of YAl₂ Particles on the Corrosion Behavior of Mg⁻Li Matrix Composite in NaCl Solution.

The strength of Mg–Li alloy is greatly improved by the composite strengthening of intermetallic compound YAl2 particles, but the low corrosion resistance of Mg–Li alloy is still the main factor that restricts the application of the alloy and its composites. In this paper, the effect of YAl2 particles on the corrosion behavior of Mg–Li alloy was systematically investigated. The results showed that the corrosion resistance of YAl2p/LA143 composite could be significantly improved, accounting for the formation of a transitional interface layer by adding YAl2 particles. The diffusion of yttrium and aluminum atoms from YAl2 particulates improved the stability of the surface film and enhanced the adhesion between the corrosion products and the substrate, which hindered further expansion of pitting.

11B and 89Y solid state MAS NMR spectroscopic investigations of the layered borides YTB4 (T = Mo, W, Re).

The YCrB4 type borides YTB4 (T = Mo, W, Re) were synthesized from the elements by arc-melting and subsequent annealing. The structures were refined from single crystal X-ray diffractometer data: Pbam, a = 602.84(8), b = 1164.5(1), c = 361.20(4) pm, wR2 = 0.0404, 624 F2 values, 26 variables for YMoB4, a = 603.00(7), b = 1165.1(1), c = 360.63(6) pm, wR2 = 0.0487, 474 F2 values, 26 variables for YWB4, and a = 596.67(6), b = 1154.4(1), c = 360.21(4) pm, wR2 = 0.0465, 544 F2 values, 26 variables for YReB4. The boron atoms build up planar networks which are a tessellation of slightly distorted pentagons and heptagons. Adjacent networks coordinate the transition metal and yttrium atoms in the form of pentagonal and heptagonal prisms, respectively. The four crystallographically distinct boron sites are differentiated by high-resolution 11B solid state isotropic magnetic shifts and nuclear electric quadrupolar coupling constants. Partial site assignments are possible based on comparisons with electric field gradient calculations using the WIEN2k code. 89Y MAS NMR spectroscopic studies suggest substantially weaker Knight shift contributions to the resonance frequencies when compared to other intermetallic yttrium compounds, including other ternary yttrium boride compounds measured previously.

Electronic and magnetic behaviour of 2D metal structures of Y on Li(1 1 0) surface

We investigated the bond relaxation and electronic and magnetic behaviour of yttrium (Y) atoms adsorbed on lithium (Li)(1 1 0) surface by using a combination of bond-order-length-strength (BOLS) correlation and density-functional theory (DFT). We found that adsorption of Y atoms on Li(1 1 0) surfaces forms two-dimensional (2D) geometric structures of hexagon, nonagon, solid hexagon, quadrangle and triangle. Their magnetic moments are 6.66 µB, 5.54 µB, 2.81 µB, 0.28 µB and 1.04 µB, respectively. In addition, this work could pave the way for design of new 2D metals and understanding of their electronic and magnetic properties.

Exploring the Structure, Energetic, and Magnetic Properties of Neutral Small Lithium Clusters Doped with Yttrium: Supermagnetic Atom Research.

Density functional theory calculations based on magnetic and energetic stability criteria were performed to study a series of yttrium-doped lithium neutral clusters. A relativistic approximation was employed to properly describe the energy and multiplicity of the given clusters’ fundamental states. The interaction of the 4d-Y atomic orbitals with the sp-Li states had an important role in the magnetic and energetic behavior of the selected systems. The spin density was concentrated over the yttrium atom regardless of the size of the cluster. Li7Y is a new stable superatom due to its enhanced magnetic properties.

Multilayer structure of Al-Si alloy after electro-explosion alloying with yttrium oxide powder

Electro-explosion alloying of a eutectic Al-Si alloy (silumin) with yttrium oxide powder is carried out to form a coating on the material surface with advanced characteristics. Transmission microscopy of thin foils and x-ray micro-spectral analysis are performed to identify the elemental and phase composition and the defect substructure of the coating. The study reveals a four-layer structure comprising a surface layer (1), interlayers (2 and 3), and an interjacent (4) layer, with thicknesses ranging from 100 to 900 nm, as well as a multi-phase nanocrystal structure consisting mostly of aluminium and yttrium oxides and silicates. It is established that the coating is a multi-element alloy, and that its main components are oxygen, aluminium, yttrium, silicon and titanium (oxygen and yttrium atoms are located in layers 1, 2 and 4, aluminium atoms in layer 3, and silicon and titanium atoms in layers 1–3).

Superconducting Phase Diagram of the Yttrium, Barium, and YBa-core in YBa2Cu3O7–δ by an Ising Model

We investigate the temperature dependent of magnetizations, hysteresis properties and present the superconducting phase diagrams of the YBa2Cu3O7–δ (YBCO) by an Ising model within the effective-field theory. We obtain the magnetizations of the YBCO and its components (Cu1, Cu2, O1, O2, O3, O4, Ba, Y, CuO-shell, YBa-core, and total YBCO) versus the reduced temperature and external magnetic field. We find that the copper atoms have two different magnetizations (Cu1 and Cu2) and oxygen atoms have four different magnetizations (O1, O2, O3, O4) but yttrium and barium has one magnetization. The differences in the magnetizations of the copper and oxygen atoms result from the lattice location of them on the YBCO lattice. The magnetization of the Cu1 atoms is the lowest and the yttrium is highest than those of the others; hence magnetizations of the YBCO increase from the corner to inner of the orthorhombic YBCO lattice. We also find that the YBa-core, yttrium and barium atoms of the YBCO exhibit superconductivity behaviors. Therefore, Y–Ba core, yttrium and barium atoms have the superconducting phase diagram and it has Meissner, vortex, and normal states. It is also found that the upper critical coercive field (Hc2) and the critical vortex temperature (Tv) of the Ba are high than those of the Y and YBa-core.