High-purity Yttrium Oxide Research Articles

Influence of a neutron beam on the electrical properties of nanosized Y2O3 crystals

In the presented work, high purity yttrium oxide (99.99%), nanosized crystal density 0.069 g/cm3, specific surface area 100-150 m2/g, average crystal size 8-10 nm and difrent intensities (4.0×10 12 n/cm2, 1.3×10 13 n/cm² and 4.0×10 14 n/cm²) in the temperature range of 300-700 K, the electrical properties were investigated after irradiation with fast neutrons. It has been established that the electrical properties of Y 2 O 3 nanocrystals in a wide temperature range show an increase in the electrical conductivity according to a linear law after irradiation of various intensities. The increase in conductivity depending on the intensity of fast neutron radiation is due to the predominance of yttrium vacancies in the conductivity.

Effect of temperature on the preparation of yttrium oxide in microwave field

High-purity yttrium oxide (Y2O3) powder is successfully prepared by microwave-assisted calcination of yttrium oxalate. The decomposition process of yttrium oxalate was analyzed by TG-DSC indicate formation of Y2O3 undergoes three stages. The X-ray diffraction (XRD) analysis indicates that there is no peak of yttrium oxalate hydrate (Y2(C2O4)3‧10H2O) after microwave-assisted calcination at 600 °C for 2 h, with the formation of cubic crystalline Y2O3 structure. Fourier transformed infrared spectroscopy (FT-IR) analysis show similar results with emergence of Y2O3 after calcination at 600 °C for 2 h. The precursor had a median particle size diameter 30.719 μm, while that of all the calcined powders at different temperatures significantly decreased to about 4 μm. Scanning electron microscopy (SEM) observations demonstrate the morphologies of the precursor and product, and the calcined Y2O3 preserved the amorphous character of the precursor, with rod-like shape. All the TG-DSC, XRD, FT-IR and SEM were utilized to understand the molecular changes in the process of microwave-assisted calcination of Y2(C2O4)3 to Y2O3.

Structural, electrical and magnetic features of Kagomé YBaCo4O7system

AbstractPolycrystalline yttrium barium cobaltite (YBaCo4O7) powdered sample was prepared by conventional solid state reaction route using high purity yttrium oxide, barium carbonate and cobalt oxide. The as-prepared sample was characterized by XRD diffraction, SEM/EDAX, Raman analytical techniques, resistivity and magnetization measurements for structural, morphological, electrical and magnetic properties assessment. XRD pattern confirms the single phase formation of the sample without any impurity. SEM image shows the hexagonal growth of the crystal and EDAX spectrum reveals stoichiometric composition of as prepared sample. The variation in electrical resistivity from 90 K to 300 K follows the variable range hopping conductivity mechanism. The strong broad overlapped Raman peaks of Co–O and Y–O stretching and bending vibrations of tetrahedral CoO4with included components of YO6of octahedral symmetry are obtained at 542 cm−1, 486 cm−1and 636 cm−1, 436 cm−1, respectively. DC magnetic susceptibility exhibits very weak ferromagnetism below 80 K and does not obey Curie-Weiss law.

A solvent extraction process with mixture of CA12 and Cyanex272 for the preparation of high purity yttrium oxide from rare earth ores

Solvent extraction and separation of yttrium from other rare earths in chloride medium using the mixture of sec-octylphenoxy acetic acid (CA12, HA) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272, HB) has been investigated. Tri- n-butyl phosphate (TBP) was used as the phase modifier to achieve fast phase separation and to improve the stability of the organic phase. The separation coefficients (β) between yttrium and heavy rare earths (HRE) are more significant in the double solvent (HAB) extraction system than the CA12-TBP extraction system. In a laboratory scale test with a fractional extraction process including 15 stages of extraction section and 10 stages of scrubbing section, yttrium was separated from all the other rare earths with a yield of 95% and an yttrium oxide product with 99.94% purity was obtained.

Fluorimetric determination of traces of europium(III) using a new chelator and acetate or phosphate in dimethylsulfoxide as enhancers

A new Schiff-base ligand [N, N′, N″-Tri- (2,4-dihydroxyacetophenone) – triaminotriethylamine (TDATA)] with a tripodal structure was synthesized. Its fluorescence intensity with the europium(III) complex was increased about 178-fold in the presence of sodium acetate (NaAc) and about 126-fold in the presence of sodium phosphate (Na3PO4) solution. After adding the organic solvent dimethylsulfoxide (DMSO) to the above system, which leads to Eu3+ the fluorescence was further enhanced about 12-fold. Spectrofluorimetric determination of trace amounts of Eu3+ based on the phenomenon was performed. The excitation and emission wavelength is 365 nm and 615 nm, respectively. Under optimum conditions, the fluorescence intensities vary linearly with the concentration of Eu3+ in the range of 4.9 × 10−12–3.2 × 10−6 mol · L−1 with a detection limit of 4.5 × 10−12 mol · L−1 (for the TDATA-NaAc-DMSO system) or 6.2 × 10−11–8.6 × 10−6 mol · L−1 with a detection limit of 6.0 × 10−11 mol · L−1 (for the TDATA-Na3PO4-DMSO system). Interferences of some rare earth metals and other inorganic ions are described. The method is a selective, sensitive, rapid and simple analytical procedure for the determination of europium(III) in a high purity yttrium oxide and synthetic sample. The mechanism for the fluorescence enhancement is also discussed.

Determination of trace europium(III) based on a new fluorescence enhancement system of europium(III) with N,N′-bis-(4-N-aminothiourea-2-amylidene)-4,4′-diaminodiphenyl sulfone by EDTA or alumin in N,N-dimethylformamide

A new bis-Schiff base ligand, N,N′-bis-(4-N-aminothiourea-2-amylidene)-4,4′-diaminodiphenyl sulfone (ARADS), was synthesized. The solutions of its complex with Eu3+ in DMF can emit the intrinsic fluorescence of Eu3+. The fluorescence intensity of the complex was enhanced 20–30-fold in the presence of EDTA (or alum). The influence of seven kinds of solvents (DMF, CH3CN, THF, acetone, CH3OH, C2H5OH, and DMSO) on the intensity of fluorescence was studied. The results showed that the Eu3+-ARADS-EDTA (or alum) system emits its strongest fluorescence in DMF. Thus, the system can be used to develop a new method for the determination of europium(III). The excitation and emission wavelengths are 395 and 615 nm, respectively. Under optimal conditions, the fluorescence intensities vary linearly with the concentration of Eu3+ in the range 6.0 × 10−10−5.2 × 10−5 mol/L, with a detection limit of 5.0 × 10−10 mol/L. The interference from some rare earth metals and other inorganic ions are described. The method is a selective, sensitive, rapid, and simple analytical procedure for the determination of europium(III) in high-purity yttrium oxide and synthetic samples. The mechanism of fluorescence enhancement was also studied.

The New Fluorescence Enhancement System Eu 3+ -ARADE-HMTM-Al 3+ and its Analytical Application

A new bis-Schiff base ligand, N,N′-bis-(4-N-aminothiourea-2-amylidene)-4,4′-diaminodiphenyl ether (ARADE), was synthesized. Its complex with Eu3+ in DMF emits the intrinsic fluorescence of Eu3+. The fluorescence intensity of the Eu3+-ARADE system was enhanced about 60-fold by the addition of hexamethylene tetramine (HMTM) and potash alum. This is a new fluorescence enhancement phenomenon. The excitation and emission wavelengths are 375 nm and 615 nm, respectively. Under optimal conditions, the fluorescence intensities vary linearly with the concentration of Eu3+ in the range of 7.8×10−9–1.75×10−5 mol·L−1 with a detection limit of 5.2×10−9 mol·L−1, or with the concentration of Al3+ in the range of 3.1×10−7–9.7×10−5 mol·L−1 with a detection limit of 2.7×10−7 mol·L−1. The interferences of some rare earth metals and other inorganic ions were described. This method was applied to the determination of Eu3+ in high purity yttrium oxide and the analysis of Al3+ in alloy steel standard samples. The mechanism of fluorescence enhancement was also studied.

Determination of trace terbium(III) with N, N', N"-tri(3-indolemethanal)triaminotriethylamine based on a new fluorescence enhancement system.

A new Schiff-base ligand with a tripodal structure, N,N',N"-tri(3-indolemethanal)triaminotriethylamine (TTAIM), was synthesized. Its fluorescence intensity with terbium(III) was increased by about two orders of magnitude in the present of sodium acetate (NaAc). After the adding of the organic solvent dimethyl sulfoxide (DMSO) to the above system, leading to Tb3+ the fluorescence was further enhanced by about 16 fold. The spectrofluorimetric determination of a trace amount of Tb3+ based on this phenomenon was carried out. The excitation and emission wavelengths were 330 nm and 545 nm, respectively. Under the optimal conditions, the fluorescence intensities varied linearly with the concentration of Tb3+ in the range of 5.7 x 10(-11) - 6.3 x 10(-6) mol L(-1) with a detection limit of 5.0 x 10(-11) mol L(-1). The interferences of some rare earth metals and other inorganic ions were described. The method is a selective, sensitive, rapid and simple analytical procedure for the determination of terbium(III) in a high-purity yttrium oxide and synthetic sample. The mechanism for the fluorescence enhancement was also studied.

Determination of Trace Terbium(III) Based on New Fluorescence Enhancement System of Terbium(III) with 1,7- bis- (2′-Carboxylphenyl)-1,4,7-trioxaheptane by Sodium Acetate in Dimethyl Sulfoxide

A new ligand; 1,7-bis-(2′-carboxylphenyl)-1,4,7-trioxaheptane (BCPTH), its fluorescence intensity with terbium(III) was increased by more than two orders of magnitude in the present of sodium acetate (NaAc) or hexamethylene tetramine (HMTM) solution. Following the addition of organic solvents to the above system leading to the Tb3+ fluorescence was further enhanced by about an order of magnitude. The enhancement was observed to be highest with NaAc and dimethyl sulfoxide (DMSO) solvent. The spectrofluorimetric determination of trace amount of Tb3+ based on the phenomenon was carried out. The excitation and emission wavelengths are 296 nm and 545 nm, respectively. Under optimal conditions, the fluorescence intensities vary linearly with the concentration of Tb3+ in the range 7.0 × 10−9 M–4.8 × 10−5 M with a detection limit of 5.0 × 10−9 M. The interferences of some rare-earth metals and other inorganic ions are described. The method is a selective, sensitive, rapid, and simple analytical procedure for the determination of terbium(III) in a high purity yttrium oxide and synthetic sample. The mechanism for the fluorescence enhancement was also studied.

Determination of trace europium based on new ternary fluorimetric enhancement system of europium(III) with thenoyltrifluoroacetone and trisalicylicamido triethylamine

In this work, a newly synthesized ligand, trisalicylicamido triethylamine, acts as a specific reagent for enhancing the fluorescence intensity of EuIII complex with thenoyltrifluoroacetone. The spectrofluorimetric determination of trace amounts of EuIII based on the above system was carried out and its luminescence mechanism was studied. The excitation and emission wavelengths are 348.9 nm and 613.4 nm, respectively. The fluorescence intensities vary linearly with the concentration of EuIII in the range 7.598 × 10–7 g l–1–3.799 × 10–4 g l–1 with a detection limit of 1.520 × 10–8 g l–1 and a standard deviation of 1.80 × 10–6 g l–1 for 10 measurements. The interferences of some rare-earth metals and inorganic ions are described. This method is a direct, rapid, selective and sensitive analytical procedure for the determination of trivalent europium in high purity yttrium oxide.

An ICP-AES method for the determination of heavy rare earth elements (Eu-Lu) in high purity yttrium oxide

Traces of heavy rare earth elements (Eu-Lu) were determined in high purity yttrium oxide by inductively coupled plasma atomic emission spectrometry. The yttrium oxide samples were dissolved in nitric acid and the solutions analyzed with a plasma produced by a 56 MHz RF generator at an output power of 1.5 kW. Using a high resolution sequential monochromator, interference-free spectral lines for Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu could be found for calibration. The detection limits for the above elements have been found to be slightly higher in the presence of yttrium matrix, than in aqueous solution. This could be attributed to background enhancements due to the presence of yttrium. The mean RSD of the method varied between 2.3% and 6.3% in the concentration range 0.01 and 0.5 μg/ml. The percentage recovery ranged from 84 to 106 for the different rare earth elements.

DETERMINATION OF TRACE AMOUNT OF LA, CE, SM, CU, AL AND PB IN HIGH-PURITY YTTRIUM OXIDE WITH INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROMETRY

Numerical derivative techniques have been studied for the correction of spectral interferences in the determination of trace impurities in high-purity yttrium oxide with ICP-AES. The results showed that the derivative techniques not only eliminated the spectral interferences from the matrix, but also reduced the effect of the interferences on detection limit. Compared to original spectrometry, the derivative spectrometry significantly improved the ''true detection limits''. At low analyte concentrations,the derivative techniques yielded more reliable quantitative results than the traditional off-peak and on-peak correction methods

Thermogravimetrical investigation of the synthesis and annealing of YBa 2Cu 3O n

The synthesis and calcination of yttrium - barium - cuprate are gravimetrically investigated using high purity yttrium oxide, barium carbonate and copper oxide as source and reference materials. The rate of synthesis in a 1 atm oxygen environment is much less than that in air. The final stoichiometric number n of pellets becomes 6.72 + 0.05 at room temperature after firing for at least 50 hrs at 9̄50°C and slow cooling at 0.6°C/min both in air and in pure oxygen. After repeated heat treatments a maximum evolution rate of oxygen is obtained at n = 6.45 at about 660°C for pure oxygen and at about 640°C for air, while a maximum rate of incorporation appears near n = 6.5 at about 560°C for pure oxygen, and at about 450°C for air.

Determination of trace rare earth impurities in high-purity yttrium oxide by using ion-exchange separation and spectroscopic method

Since the sensitivity of direct emission spectroscopic method is not enough to analize rare earth impurities in high-purity rare earth oxides, a separation and pre-concentration step is always required. In the present paper, a cation exchange spectroscopic method is described. α-Hydroxyisobutyric acid is used as an efficient eluant to separate La, Ce, Pr, Nd, ▪ ▪ Sam and Eu from matrix yttrium. The concentrate is then determined by using solution dry-residue method. The detection limits are located in the range of 0.008 to 0.03 ppm (for a concentration factor of 10 000), and the variation coefficients are from 12 to 15%. Ion-exchange Separation and Pre-concentration. α-Hydroxyisobutyric acid (α-HIBA) is and excellent eluent for the separation of Lanthanon [1]. Therefore, we selected α-HIBA as an eluent to separate La, Ce, Pr, Nd, Sm and Eu from matrix yttrium. In order to indicate the separation process, Eu (152, 154) t001 Sample Analysis Results Element Present μ/g Added μ/g Total μ/g Found μ/g Recovery % Average % La 2O 3 0.08 0.1 0.18 0.14 78 91 0.45 0.25 0.70 0.72 103 0.46 1.00 1.46 1.45 99 1.30 2.50 3.80 3.20 84 CeO 2 0.20 0.50 0.70 0.60 86 96 0.96 0.25 1.21 122 101 1.71 1.00 2.71 2.75 101 4.30 2.50 6.80 6.60 97 Pr 6O 11 0.05 0.40 0.40 0.36 90 94 0.20 0.25 0.45 0.42 93 1.30 1.00 2.30 2.30 100 3.25 1.50 4.75 4.40 94 Nd 2O 3 0.20 0.40 0.60 0.56 93 92 2.50 1.00 3.50 3.40 97 0.53 0.25 0.78 0.66 85 2.80 2.50 5.30 5.00 93 Sm 2O 3 0.05 0.40 0.40 0.34 85 95 0.30 0.50 0.80 0.72 90 1.20 1.00 2.20 2.20 100 0.98 2.50 3.48 3.60 103 Eu 2O 3 0.03 0.25 0.28 0.22 79 93 0.34 1.00 1.34 1.45 106 was used as a tracer. The comparison was made between porous cation resin (home made) and Zerolit 225 cation resin, and the experimental results are given in Fig. 1. The results obtained show that the porous resin has better properties than Zerolit 225 resin in the separation of rare earth impurities from matrix yttrium. The main separation parameters are as follows: column length: 2 × 50 cm; resin size: ∼200 mesh; concentration of the eluent (α-HIBA): 0.15 M (pH 5,4) for Y, 0.5 M (pH 5.4) for La, Ce, Pr, Nd, Sm, Eu. Under these conditions the rare earth impurities (LaEu) can be completely separated from matrix yttrium, the matrix residue amount is less than 100 μg for 1 g of Y 2O 3 on the column. Typical results are shown in Fig. 2. Spectroscopic Determination. The solution dry-residue method with high absolute sensitivity was adopted to analyze the concentrate of rare earths. The detailed studies on carrier influence, matrix effect, and controlled atmosphere ratio (Ar: O 2) were made in this paper, and the adequate conclusions are given below: 1. The addition of alkali elements increases the line intensities of rare earths, the increasing order is Cs > Rb > K > Na; 2. The line intensities of La, Ce, Pr, Nd, Sm and Eu are rising with the concentration of CsCl, the optimal concentration range of CsCl in solution dry-residue method is from 5 to 20 mg/ml. If its concentration is higher than 20 mg/ml, the increase of the background and the decrease of the line intensities of rare earths will be observed (Fig. 3). 3. The influence of matrix yttrium and third elements in concentrate should be considered. The experimental results show that the permissive maximum amounts of Y 2O 3 and CaO are 6 mg/ml and 5 mg/ml respectively. 4. Controlled atmosphere ratio of 4:1 (Ar:O 2) was employed, and the gas-chamber used is shown in Fig. 4. Sample Analysis. Analytical results for La, Ce, Pr, Nd, Sm, Eu in high-purity Y 2O 3 are listed in Table 1.

Concentration of yttrium subgroup impurities in high-purity yttrium oxide by TBP-NH 4SCN extraction chromatography

Separation factors for all the yttrium subgroup elements and yttrium, extracted with TBP from 0.45 M NH 4SCN solution at 24–42° have been determined and found to be ⩾ 1.9. Eight yttrium subgroup impurities in high-purity yttrium oxide have been concentrated by means of TBP-NH 4SCN extraction chromatography at 32° before spectroscopic determination. Analysis of one real sample and two synthetic samples gave average recoveries of 80–100%.

The determination of trace rare earth elements in high-purity yttrium oxide by inductively coupled plasma-atomic emission spectroscopy

A method using a 3.5 kW argon ICP as radiation source and a 1-m grating plane spectrograph is described for the determination of trace amounts of 14 rare earth elements in high-purity yttrium oxide. Detection limits for most rare earth elements were 0.3 to 3 μ;g g −1 with exception of Ce and Pr, and relative standard deviations were 0.023 to 0.073 except for Ce and Pr. By a “dilution method” the optimum concentration of the matrix (Y 2O 3) in solution was found to be about 30 mg ml −1. Influences of interference elements were studied, and a table for correcting spectral interference of several lines was made. At the range of tested concentration (1100 μ;g ml −1 for each rare earth element, Fe, Cu, Cr, Ni, Mn, V, Ti, Ba, Al and Mg; 4300 μ;g ml −1 for Na; 11000 μ;g ml −1 for Ca), influences were found to be negligible. The precision of the method may be improved if an internal reference is applied, and changing acid concentration from 2N to 4N HC1 does not affect the results. This method could be used to analyze yttrium oxide with 99.99% purity. The experimental results show that the method is superior to the d.c. arc powder method in many respects.

Determination of trace amounts of rare earth elements in high purity yttrium oxide by inductively coupled plasma-atomic emission spectroscopy

誘導結合高周波アルゴンプラズマ(ICP)発光分光分析法による高純度酸化イットリウム中の14種類の微量不純物希土類元素の分析法を検討した.市販品の99.9999%(希土類ベース)の酸化イットリウムを基本物質として用い,これに各種の不純物希土類元素を添加して標準試料系列を調製した.試料は塩酸に溶解して1%水溶液としてから測定した.酸化イットリウム濃度及び塩酸濃度の増加は全測定元素のスペクトル線強度を減少させるので,分析試料と標準試料の各濃度を等しくして測定することとした.本法による分析精度は全元素とも変動係数2%以内であり,定量下限はルテチウム,イッテルビウムに対して0.2ppm,ランタン,ユーロピウム,ジスプロシウム,エルビウムに対して0.5ppm,ホルミウム,ツリウムに対して1ppm,プラセオジム,ネオジム,ガドリニウム,テルビウムに対して2ppm,サマリウム,セリウムに対して3ppmである.なお,市販品の酸化イットリウム{(99.9～99.99)%品}中の不純物希土類元素を本法で分析した結果は,質量分析法で分析した結果と良好な一致を示し,本法により高感度,高精度かつ迅速に高純度酸化イットリウム中の微量不純物希土類元素の定量を行えることが分かった.

An XRF method for the determination of common rare earth impurities in high purity yttrium oxide

An XRF method for the determination of Eu, Gd, Tb, Dy, Ho, Er and Yb in yttrium oxide has been developed. The samples are converted to yttrium oxalate and presented to the spectrometer in the form of pressed pellets. Philips PW-1220, semiautomatic X-ray spectrometer is used for analysis. Analysis lines have been chosen after careful study of line interferences. The lower estimation limit for Yb is 0.01% and for other elements it is 0.005%. The method has been tested for its accuracy by analysing synthetic samples with known composition.

Precise and rapid determination of trace amounts of uranium in inorganic samples by neutron activation and TBP extraction

Neutron activation analysis is one of the very few annlyticnl techniques that can be used for rcliuble determination of uranium ut the p.p.lOy concentration level. A very sensitive version is the one based on measurement of 23.5-min 239U originating from the (n, 11) reaction in 2JEU. provided that u selective and rapid separation procedure giving high chemical yield is avuilable. Such a procedure might be based on extraction with tri-n-butyl phosphate (TBP) from nitric acid media, which has been extensively used in nuclear fuel reprocessing work. It was recently shown’ that urunium could be determined in fresh water by a singleextruction into TBP from ( 1 -II) nitric acid. When the need arose for uranium determination in high-purity yttrium oxide. it was decided to study the applicability of the TBP-HN03 system on a wider range of samples. Distribution coefficients for more than 70 elements in the T&P-HN03 system ha& been given2. According to these data extraction from 5 M nitric acid into 25% TBP seemed to be the optimal choice. In 100% TBP. it would be necessary to go down to l-2 M nitric acid in order to remove efficiently a number of elements including yttrium and the heavy rare earths, and at those low concentrations the uranium yield would probably be unsatisfactory. In the case of 25x, TBP, only Au. Th und Np would be extracted along with uranium from 8 5 M nitric acid solution to any significant degree. This would allow the determination of thorium uiu 22.4-min 233Th simultaneously with uranium.

Emission-spectrometric determination of trace non-rare earth elements in yttrium oxide using AgF-Ga2O3 mixed carrier

An emission-spectrometric method is described for the quantitative determination of traces of non-rare earth elements in yttrium oxide, employing addition of AgF-Ga2O3 mixed carrier. This addition effects an increase of the rate of evaporation of the analytical elements and of the number of atoms in the arc plasma. It enhances the sensitivity of the analytical elements to a larger extent than other carriers and permits the determination of microquantities of the elements (Mg, Ca, Mn, Co, Fe, Pb, Cu, Cd, Al, B, Sn, As, Bi) within limits of detection from 0.1 to 13 ppm in high-purity yttrium oxide. The coefficients of variation are less than 20%.