YPO4 Research Articles

Separation and Concentration of Trace Lead by Coprecipitation with Yttrium Phosphate

Abstract Yttrium phosphate coprecipitates quantitatively lead and iron(III) and hardly does chromium(III), manganese(II), cobalt, nickel, copper, and zinc and alkali and alkaline earth metals at pH about 3. The determination of lead separated and concentrated by the coprecipitation was demonstrated using flame atomic absorption spectrometry.

Polymerized Organic‐Inorganic Synthesis of Mixed Oxides

A new and simple chemical route has been used to synthesize mixed‐oxide powders. The method uses long‐chain polymers, such as poly(vinyl alcohol) and poly(ethylene glycol). The chemistry of the precursor solution differs from other solution‐polymerization techniques. The stabilization of the cations in the precursor is established not only through the chemical binding of cations with the functional groups, but also, in major part, through the physical entrapment of the metal ions in the network of the dried polymer carrier. Pure, single‐phase calcium aluminate, yttrium aluminate, and yttrium phosphate powders have been produced, while maintaining a 4:1 ratio of positively charged valences of the cations (Men+) to negatively charged hydroxyl (‐OH−) groups. The ceramic yield of the new method (the ratio of the weight of the ceramic powders to the weight of the organics that are used in the preparation) is ∼2.

An Investigation of the Chromaticity of Blue Emitting Yttrium Silicate

ABSTRACTThis investigation studied the effects of Ho3+ and Er3+ on the luminescence of the blue emitting phosphor yttrium silicate, (Y1-mCem)2SiO5. Yttrium silicate has a large emission tail that extends into the red portion of the visual spectrum. To improve the chromaticity of this phosphor to give it a more saturated blue color, the emission intensity of the tail needs to be decreased. Photoluminscence and low-voltage cathodoluminescence measurements were performed on yttrium silicate phosphors with varying concentrations of Gd3+, Ho3+ and Er3+. It was found that when co-doping with Ho3+ and Er3+, the relative intensity of the emission tail was decreased, but so to was the overall luminescence intensity of this phosphor.

An Investigation of the Chromaticity of Blue Emitting Yttrium Silicate

ABSTRACTThis investigation studied the effects of Ho3+ and Er3+ on the luminescence of the blue emitting phosphor yttrium silicate, (Y1−mCem)2SiO5. Yttrium silicate has a large emission tail that extends into the red portion of the visual spectrum. To improve the chromaticity of this phosphor to give it a more saturated blue color, the emission intensity of the tail needs to be decreased. Photoluminscence and low-voltage cathodoluminescence measurements were performed on yttrium silicate phosphors with varying concentrations of Gd3+, Ho3+ and Er3+. It was found that when co-doping with Ho3+ and Er3+, the relative intensity of the emission tail was decreased, but so to was the overall luminescence intensity of this phosphor.

Fracture of multilayer oxide composites

Ceramics with high strength and damage tolerance have been realized in the well-recognized non-oxide systems, e.g. silicon carbide/graphite and silicon carbide/boron nitride laminates. All-oxide systems without compliant materials functioning as do graphite and boron nitride are still facing the problem of catastrophic failure. In this study, ten kinds of multilayered, all-oxide laminates fabricated by a low-cost tape casting technique were evaluated. These materials were yttrium phosphate (YPO 4)- and lanthanum phosphate (LaPO 4)-containing zirconia (ZrO 2) laminates, and aluminum phosphate (AlPO 4)-containing alumina (Al 2O 3) laminates. A YPO 4-containing ZrO 2 laminate demonstrated excellent strength and improved damage tolerance. A LaPO 4-containing ZrO 2 laminate also displayed a satisfactory result. An AlPO 4/Al 2O 3 laminate was weak. The AlPO 4/Al 2O 3 laminate was strengthened by reinforcing AlPO 4 layers with Al 2O 3, while retaining non-brittle fracture. Different flexural behaviors in different oxide laminates were discussed.

Rare earth and yttrium phosphate solubilities in aqueous solution

Rare earth and yttrium phosphate solubility products range over more than 1 order of magnitude. Minimum solubilities are observed for light rare earths between Ce and Sm. For the elements Ce, Pr, Nd, and Sm solubility products (log K sp 0 ( M) = log ([ M i 3+] [PO 4 3−])) at zero ionic strength and 25°C can be approximated as log K sp 0,( M) = −26.3 ± 0.2. Rare earth phosphate solubility products for well-aged, coarse precipitates increase substantially between Sm and Lu, with log K sp 0(Lu) estimated as −24.7. The solubility product of Y is similar to that of Ho (log K sp 0 (Y) = −25.0) and is much higher than those of all light rare earths. The solubility product of La is substantially larger than that of Cc (log K sp 0 (La) − log K sp 0 (Ce) ≈ 0.5). Solubility products are strongly dependent on the conditions of solid phase formation. Fresh precipitates are much more soluble than slowly formed, well-aged, coarse precipitates. The pattern of rare earth and yttrium phosphate solubility products is generally similar to the fractionation patterns which are developed during phosphate coprecipitation.

Luminescent Properties of Some Rare Earth Phosphates

Abstract Luminescent properties of scandium and yttrium phosphates are discussed and mechanisms involving their emissions proposed.

Characterization of Yttrium Phosphate and a Yttrium Phosphate/Yttrium Aluminate Laminate

Single‐phase yttrium phosphate (YPO4) and a YPO4/yttrium aluminate (Y3Al5O12) laminate were studied. Young's modulus, Poisson's ratio, Vickers hardness, and coefficient of thermal expansion of YPO4 sintered bodies were measured. YPO4 and Y3Al5O12 are chemically compatible and morphologically stable up to at least 1600°C. The fracture behaviour was studied by four‐point flexural testing on bars with ground or notched tensile surfaces, and by the indentation method. Noncatastrophic fracture could be seen in these specimens. In flexural testing, cracks could be bridged by YPO4 layers, followed by some interfacial debonding. Indentation responses also consistently showed some interfacial delamination in the YPO4/Y3Al5O12 laminate.

Low-temperature specific heats of lanthanum and yttrium phosphate glasses

The specific heats of (R2O3)x(P2O5)1−x glasses containing high concentrations of La3+ and Y3+ ions have been measured between 1.5K and 30K. It is shown that, in addition to the usual Debye contribution, there is an excess specific heat arising from localized vibrational states which has been discussed in terms of two distinct models. The first predicts a maximum in the temperature dependence of the excess specific heat associated with the crossover frequency from phonon to fracton behaviour. The phonon-fracton density of states used to fit the excess specific heat gives rise to model parameters having the same magnitudes as those found previously for other glasses including samarium phosphates. The second model, formulated on the basis of soft vibrations in glasses, predicts a minimum in the excess specific heat, which is also observed.

Phase equilibria in the system Y 2O 3 — CaO — P 2O 5: The partial system YPO 4 — Ca 2P 2O 7 — Y 2P 4O 13

Within research on calcium-yttrium phosphates the phase diagram of partial system YPO 4 — Ca 2P 2O 7 — Y 2P 4O 13 has been determined. One ternary compound with the formula CaYP 3O 10 occurs in this system. It is formed at section Y 2P 4O 13 — Ca 2P 20 7 at the 1:1 molar ratio of initial phosphates. Compound CaYP 3O 10 is unstable in air at high temperatures. The temperatures of decomposition were found to change according to thermal treatment that had been used. It was proposed that CaYP 3O 10 is decomposed in air to Y 2P 4O 13 at approx. 1160°C and then yttrium orthophosphate YPO 4 is formed at 1210°C.

Solubility products of the trivalent rare-earth phosphates

The solubility and solubility products of 14 rare-earth phosphates in aqueous solution have been determined at 25±1°C. The most soluble compound is yttrium phosphate (pK=24.76). The least soluble ones are lanthanum phosphate (pK=26.15) and ytterbium phosphate (pK=26.17). The rare-earth phosphates were prepared by precipitation from homogeneous solution. Saturated solutions were analyzed for pH, the concentrations of some rare-earth cations, and the total concentration of phosphate. Activity products were calculated from the experimental data

Optical effects in irradiated yttrium orthophosphate doped with Tb, V, and Nb

Optical effects in irradiated yttrium orthophosphate doped with Tb, V, and Nb

Infrared spectra of the dihydrates of calcium selenate and yttrium phosphate - comparison with the spectrum of gypsum

The infrared spectra of protiated and deuterated CaSeO 4·2H 2O and YPO 4·2H 2O were compared with the spectrum of gypsum (CaSO 4·2H 2O) with which the two investigated compounds are almost certainly iso- structural. From the position of the bands in the OD stretching region of the spectra of partly deuterated compounds having low deuterium content, one may conclude that the strength of the hydrogen bonds which water molecules form with the anions increases in the order sulfate, selenate, phosphate. While studying the spectra of mixed crystals, particular attention was payed to the bands originating from the stretching vibrations of the tetrahedral anions.

ChemInform Abstract: IONIC CONDUCTIVITY IN THE SYSTEM SODIUM ZIRCONIUM PHOSPHATE‐SODIUM YTTRIUM PHOSPHATE (NAZR2(PO4)3‐NA3Y2(PO4)3)

Chemischer InformationsdienstVolume 11, Issue 46 Physical Inorganic Chemistry ChemInform Abstract: IONIC CONDUCTIVITY IN THE SYSTEM SODIUM ZIRCONIUM PHOSPHATE-SODIUM YTTRIUM PHOSPHATE (NAZR2(PO4)3-NA3Y2(PO4)3) M. NAGAI, M. NAGAISearch for more papers by this authorS. FUJITSU, S. FUJITSUSearch for more papers by this authorT. KANAZAWA, T. KANAZAWASearch for more papers by this author M. NAGAI, M. NAGAISearch for more papers by this authorS. FUJITSU, S. FUJITSUSearch for more papers by this authorT. KANAZAWA, T. KANAZAWASearch for more papers by this author First published: November 18, 1980 https://doi.org/10.1002/chin.198046014Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume11, Issue46November 18, 1980 RelatedInformation

Luminescence properties of Sb 3+ in yttrium phosphates

The optical properties of Sb 3+ ion in Y 1− x Sb x PO 4 have been studied in the thermal range 2–500 K. Both emission and excitation spectra have been deconvoluted into gaussian curves. We found two strong emission bands with maxima at 3000 and 3950 Å and three excitation bands in the 2200–2500 Å region. Between 2 and 30 K, the luminescence intensity of the former emission decreases whereas that of the latter emission increases; the contrary takes place from 100 to 400 K. The nature of the excitation and emission transitions is discussed.

X-ray excited optical fluorescence of trace rare earths in yttrium phosphate and yttrium vanadate hosts. Part per giga level determination of rare earth impurities in yttrium oxide

X-ray excited optical fluorescence of trace rare earths in yttrium phosphate and yttrium vanadate hosts. Part per giga level determination of rare earth impurities in yttrium oxide

Paramagnetic resonance of Er3+ in YPO4

AbstractThe paramagnetic resonance of trivalent erbium in single crystals of yttrium phosphate has been observed at 4.2 K. The spectrum is described in terms of the appropriate spin‐Hamiltonian.

New phosphors for lamps

The method of preparation and the applications of four new phosphors are discussed in relation to their use in different types of lamps. Europium-activated yttrium phosphate vanadate made with the addition of boric acid is a red-emitting phosphor used in fluorescent high pressure mercury vapour lamps. Strontium pyrophosphate activated by divalent europium has been used in fluorescent lamps for photocopying and has enabled higher reproduction rates to be achieved. Barium strontium disilicate activated by divalent europium may find application in fluorescent lamps with improved colour rendering properties, and manganese-activitated magnesium aluminium gallate in fluorescent lamps used for xerographic reproduction.

Crystal growth and lattice parameters of rare-earth doped yttrium phosphate, arsenate and vanadate prepared by the oscillating temperature flux technique

Single crystals of rare-earth orthophosphates (RPO 4), arsenates (RAsO 4), and vanadates (RVO 4) have been grown by a flux method with use of an oscillating-temperature procedure. Crystals having the dimensions 1.5 × 1 × 15 mm, 1 × 1 × 6.5 mm, and 3 × 0.5 × 7 mm, respectively, have been produced in five-day runs. Lattive parameters of (Sc,Er)VO 4 single crystals and of (Sc,Er)PO 4 powders with various doping ratios have been precisely determined.

Polarized Spectra and Crystal-Field Parameters of Eu3+ in YPO4

Single crystals of yttrium phosphate doped with Eu3+ were investigated by means of polarized emission and absorption spectroscopy. The spectra are consistent with the known D2d site symmetry of the Eu3+ ion, and most of the observed transitions have been assigned. The energy-level structure of the 7F multiplet and the lower part of the 5D multiplet has been defined, and the former has been described in terms of a crystal-field model. The optical parameters for such a model have been calculated, and comparisons are made with similar calculations on yttrium vanadate.