Yttrium In Solution Research Articles

Preparation of spherical, monosized Y 2O 3 precursor particles

Spherical, monosized yttria precursor particles were obtained by homogeneous precipitation in aqueous solutions by reaction with the thermal decomposition products of urea. Increasing [Y 3+ above 0.05 M resulted in a deviation from spherical morphology and caused agglomeration of particles. Over the concentration range studied, excess urea did not affect particle morphology, but increased the yield. Increasing aging time appeared to increase particle size as well as to improve yield, as long as the urea was not depleted. The approximate chemical composition of the precipitate was YOHCO 3. The YOHCO 3 particles formed were amorphous to X-rays, and underwent a two-stage thermal decomposition, first forming Y 2O 2CO 3 near 180°C, and then cubic Y 2O 3 above 610°C. Generation of CO 3 2− appeared to be crucial to the formation of the solid phase. Heating the aqueous yttrium solution with trichloroacetic acid (CCl 3COOH) instead of urea as the precipitating agent produced a solid phase, while heating the same solution with formamide (HCONH 2) substituted for urea formed no precipitate.

Determination of yttrium in zirconia matrices by atomic absorption spectrometry

A rapid method is described for determining yttrium in solutions containing a large excess of zirconium using atomic absorption spectrometry. Samples are analysed in nitric acid solution, using a spectrochemical buffer which consists of potassium-EDTA and lanthanum to effect maximum absorption. A standard additions technique, in which yttrium solution is added to the sample, is used to avoid the preparation of matrix matched standards. The yttrium absorbance is measured at 410.2 nm using a dinitrogen oxide-acetylene flame. Synthetic solutions show that the procedure is sufficiently accurate to be used for the routine determination of yttrium in refractory oxides containing up to 3 mol-% of Y2O3(5.7%m/m).

Dip Coating of Zirconia and Mixed Zirconia Films

When glycols (except ethylenglycol) were added to an isopropanol solution of zirconium n-butoxide, the corresponding glycolates were formed by the alcohol exchange reaction, and the precipitation of oxide by hydrolysis was strongly suppressed. Diethylene glycol was most effective as the glycol additive for the precipitation retarder. At the glycol/alkoxide ratio of 2 in the presence of water (water/alkoxide ratio=0-5), a stable sol was obtained from which transparent zirconia sol-gel films can be obtained. The film thickness can be controlled by the alkoxide concentration, water/alkoxide ratio, and the pulling-up rate of the substrate plate. The maximum thickness of uniform transparent zirconia films obtained in one dipping-drying-heating cycle was about 1500Å. Much thicker films can be obtained by repeating the cycle. The crystal form of the zirconia films obtained at 600°-650°C on a glass substrate was tetragonal, and transformed into monoclinic above 800°C. The refractive indices and densities of the films obtained at 600°-650°C were 1.9-2.0 and 4.7-5.5, respectively. The density increased to 5.8-6.0g/cm3 by the heat treatment at 1000°C. In the present system, an aqueous solution of yttrium or calcium nitrate could be added so as to prepare tetragonal of cubic transparent films of doped zirconia, respectively. When silver nitrate solution was added, the tetragonal AgO-doped zirconia films were obtained. Furthermore, it was found that the addition of titanium and aluminium-magnesium alkoxides allowed to form mixed oxide films ZrTiO4 and spinel-doped ZrO2.

Spatial emission distribution of YO, Y I, Y II and Y III radiation in an inductively coupled plasma for the elucidation of excitation mechanisms

Vertical and radial emission profiles of radiation from yttrium monoxide (YO), atom (Y I), singly charged ion (Y II) and doubly charged ion (Y III) were measured precisely and compared with the emission pattern observed when a highly-concentrated yttrium solution was injected into the ICP. By comparing the obtained spatial emission pronies, experimental evidence has been found that argon ions contribute to excite high-level Y II lines from the atom ground state in a one-step process. The spatial profile of the excitation temperature derived from low- and high-level Y II lines reveals that charge transfer excitation occurs at off-axis positions in the initial radiation zone (IRZ), and the excitation by electron collisions is dominant in the normal analytical zone (NAZ). It is confirmed that the ICP is close to local thermal equilibrium (LTE) in the NAZ if the argon ionization temperature derived from the electron number density is used as LTE temperature.

Enthalpies of solution of lanthanide, yttrium and scandium trihalides in water and in non-aqueous solvents

We report values for the enthalpy of solution of ScCl 3, YCl 3, LaCl 3, GdCl 3, YbCl 3, YBr 3, LaBr 3, YbBr 3, ScI 3, YI 3, LaI 3 and GdI 3 in water, of ScCl 3, YCl 3, LaCl 3, GdCl 3, YbCl 3, ScI 3, YI 3, LaI 3 and GdI 3 in methanol and in dimethyl sulphoxide, of LaCl 3 in ethylene glycol, of GdCl 3 in dimethylformamide, and of LaI 3 in dimethylformamide, propylene carbonate, and ethanol. These values are related to earlier published values in similar systems, and are considered in relation to solvating properties for the cations and halide ions.

Oxidation mechanism of FeNi2025Cr5Al alloys-influence of small amounts of yttrium on oxidation kinetics and oxide adherence

S.I.M.S. and optical spectrometry were used to determine the composition of oxide scales developed on several FeNi2025Cr5AlY alloys, oxidized at high temperature (1273–1573K) under a pure oxygen atmosphere. The oxide scales were made up of an alumina layer containing a certain amount of spinel, independently of the iron and nickel content; yttrium enters in solid solution in the alumina layer. The growth of the alumina layer depends mainly on anionic diffusion, but does not obey a parabolic rate. The amount of yttrium in the alloys must be limited to 300 ppm (approximately the solubility of this element in the alloys), in order to have an optimum effect on oxidation kinetics and oxide adherence. This improvement in adherence is due to yttrium solute atoms in the alumina, rather than to mechanical keying by yttria particles.

Ultrafiltration of solutions of yttrium in trace concentrations

Ultrafiltration of solutions of yttrium in trace concentrations

Centrifugation of solutions of yttrium in trace concentrations

Centrifugation of solutions of yttrium in trace concentrations

Deviations from Matthiessen's rule in dilute solutions of yttrium in gadolinium

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Calculation of Detection Limits in Spectrographic Analysis

AbstractMethods to calculate detection limits of spectrographic techniques in terms of blank and background are described. Detection limits of “point‐to‐plane” and “plane‐to‐plane” spark excitation for spectrographic determination of Yttrium in solution are compared. The influence of electrode shape and of CsCl‐carrier addition is discussed.

Interaction between traces of yttrium and iron(III) in aqueous solutions—I: The state of yttrium in the solution

The state of trace concentrations of yttrium (using 88Y) in aqueous solutions and its interaction with ∼ 3·10 −7M and 3·10 −5M iron was investigated by the methods of dialysis, centrifugation and electromigration. It is concluded that trace yttrium (< 10 −9 M) exists in solutions of pH lower than 3·5 as simple Y 3+ ion, while at higher pH values pseudocolloids are formed. These colloids are positively charged at pH < 6 and their formation is mostly due to cation exchange of yttrium ions on the surface of fortuitous colloidal impurities. In the pH region 6–10 coprecipitation with ferric hydroxide proceeds, whereas at pH > 10 both this coprecipitation and adsorption of yttrium on to foreign colloidal impurities may take place. The resulting colloids are negatively charged. In the solutions having a concentration of 2·10 −6M Y and ∼ 3·10 −7M Fe yttrium cations prevail up to pH ∼ 7 and colloidal yttrium hydroxide is formed above pH 8. Some information on the charge on this hydroxide and that of 3·10 −5M iron(III) hydroxide has also been obtained.

The microstructures and kinetics of internally oxidized dilute zirconium-yttrium alloys

Yttria dispersions produced in alpha and beta zirconium by internal oxidation are described. They consist of particles from 0.2 to > 5 μm in diameter which are too large to produce dispersion strengthening. The composition of alloys studied ranged from 0.05 to 1.5 wt% yttrium and were oxidized at temperatures between 800 and 1600 °C. The observed oxidation kinetics and distribution of yttrium in solution after oxidation are explained in terms of the diffusion processes involved and the variation with composition of Y 2O 3 solubility in zirconium. Terminal solid solubility curves for Y 2O 3 in beta zirconium have been calculated from kinetic expressions derived for the process.

Analytical Application of X-ray Excited Optical Fluorescence Spectra III.Determination of Rare Earth Elements in Holmium Oxide and Zirconium Oxide

Holmium was analyzed indirectly by diluting it with yttrium oxide.After the solutions of holmium sample and high purity yttrium were mixed (Ho: Y=1: 100, by weight), oxalic acid solution was added to the mixture to precipitate the oxalate.The precipitate was filtered, dried and fired at 1000°C for 1.5 hours. The oxide powder thus prepared was irradiated by X-rays, and emission lines of Dy (572 mμ), Gd (315 mμ) and Eu (611 mμ) were measured. The detection limits of thes elements in holmium were 5, 50 and 30 ppm, respectively.The intensities of X-ray-excited optical fluorescence of rare earth elements in zirconium oxide were found to be strongly enhanced by addition of several per cent of thorium oxide to it.Zirconium and thorium were coprecipitated from the solution of them by ammonium hydroxide (Zr: Th=10: 1, by weight).The precipitate was filtered, dried and fired at 1000°C for 1.5 hours. Fluorescences of Pr, Eu, Er, Ho and Sm were all detectable in a mixed matrix, while only Dy, Gd and Tb showed positive responses in pure zirconium oxide.Detection limits of these elements and quenching effects due to residual impurities were also investigated.

The Adsorption and Sedimentation of Clean, Carrier-Free, Yttrium Solutions

Summary Experiments on the adsorption and Sedimentation of yttrium solutions have been carried out with solutions containing minimal suspended matter. It has been shown that such clean solutions of 'carrierfree' yttrium can be kept in polystyrene vessels, even at pH = 8 or more, with no Sedimentation taking place, and only a small amount of adsorption on to the vessel walls. It has also been shown that addition of 'Analar' water to such solutions converts the yttrium to a centrifugable form. It is suggested that the 'radiocolloidal' properties of yttrium reported in the literature are due to ion exchange adsorption of yttrium ions on to suspended particulate matter and on to surfaces.

Flame photometric determination of yttrium

A flame photometric method for the determination of yttrium in yttrium group rare earths is presented. There were three characteristic peaks in flame emission spectrum of yttrium, and two of them (599 m mu , 615 m mu ) were used to determine the amount of yttrium in 0.1N hydrochloric acid solution. The relation between log. amount of yttrium and log. intensities of the flame spectra is shown. The amount of yttrium in the impure yttrium solution extracted from xenotime was determined. The effectiveness of the method was recognized by the satisfactory recovery of yttrium added to the impure yttrium solution. It is recommended for industrial analysis. (auth)

Lattice spacings in thorium - yttrium alloys

Using all the precautions found to be necessary in previous work on the lattice spacings of very reactive alloy systems, the spacings for the face-centred cubic and close-packed hexagonal solid solutions based respectively on thorium and yttrium have been measured at a temperature of 25° C, following annealing at 750° C. The lattice spacings observed for yttrium were a = 3.6441, c = 5.7358 kX. Solution of thorium increases the c-spacing and decreases the a-spacing. By contrast the lattice spacing of thorium is only very slightly affected by the solution of yttrium. From the results of the lattice spacing measurements, and from those of a metallographic examination, the two-phase region between the cubic and hexagonal solid solutions extends from 49 to 69 at % yttrium. This is in conflict with the work of previous investigators (Eash and Carlson) and reasons for the discrepancy are discussed in terms of the effects of impurity on the relative stabilities of the two structures.

Lanthanon (Rare-Earth) Sodium Sulphate Precipitations

IN addition to using sodium sulphate in the classical manner to effect a separation of the light (cerium group) lanthanons, leaving the heavy group and yttrium in solution, I have found it advantageous to precipitate the whole of the 'soluble' double sulphates. This is achieved (except for the equivalent of 0·2 gm. per 1. of oxide) simply by salting out. In hot brine, solubilities of the yttrium group are reduced to less than 1 per cent of the minimum obtainable in practice with excess of sodium sulphate in hot aqueous solution.