Ternary System Li2O Research Articles

ВЛИЯНИЕ ПОВЫШЕНИЯ СОДЕРЖАНИЯ ОКСИДОВ НАТРИЯ И ЛИТИЯ НА ПРОЦЕСС КРИСТАЛЛИЗАЦИИ СТЕКОЛ СИСТЕМЫ Li2O–Al2O3–SiO2

In this work, glasses were synthesized based on the ternary system Li2O–Al2O3–SiO2 (LAS). The composition was modified by increasing the total concentration of alkali oxides, which made it possible to reduce the synthesis temperature to 1580 ͦС. X-ray phase analysis and dilatometric measurements have shown that the growth of LiAlSi3O8 solid solutions with a negative CTE occurs at temperatures close to the glass transition temperature in a limited time interval, which leads to an insignificant decrease in the CTE of glass ceramics. It has been found that an increase in the time and temperature of heat treatment leads to the growth of LiAlSi2O6 spodumen nanocrystals. Thus, the introduction of high concentrations of alkali oxides does not allow achieving the desired effect of lowering the thermal expansion coefficient

Impact of a Dopant Impurity Electronic Structure on Physical Properties, Defect Structure, and Features of Lithium Niobate Doping Technology

The macro- and microstructure of doped LiNbO3 crystals is studied, their transmission spectra are investigated, and the effective coefficients characterizing the dopant impurity distribution are determined. We analyze the literature data on phase diagrams of the ternary system Li2O–Nb2O5–dopant oxide and the electron configurations of dopant elements, and the results suggest that this can be used as a basis for designing technological conditions for growing doped lithium niobate crystals and predicting their quality. With p‑elements (boron), structurally and compositionally uniform LiNbO3 crystals can be grown, with the doping impurity not being incorporated in the crystal. s- and d-metals (magnesium and zinc) have a similar effect on the melt and properties of resulting LiNbO3 crystals, which have periodic domain structures and similar types of point defects. Due to their electronic structure, f-metals (cerium) bring the melt to such a structure that this enables the formation of a periodic domain structure in LiNbO3 crystals during their growth.

Effect of cooling modes on defect structure in Cu-doped LiTaO3

In this work we have study the defects structure of non-stoichiometric solid solutions of Cu-doped LiTaO3, the changes of Curie temperature with rate of % Cu2+ (mol) in rapid and slow cooling modes, allows us to analyze the defect structure of solid solutions synthesized in ternary system Li2O–Ta2O5–(CuO)2 in vicinity of LiTaO3. A simple comparison between our theoretical results and the experimental data of Tc shows that there is a cooling mode effect on the structural properties of Cu-doped LiTaO3. Consequently, our proposed models are able to describe the defect structure of Cu-doped lithium tantalate.

Analysis of Correlation between Density Variations and Defect Structure of W6+ : LiTaO3

We investigate the defect structure of non-stoichiometric solid solutions of WO3-doped LiTaO3 in correlation with the evolution of the density within our theoretical approach. The dopant concentration and the mechanism of substitution, which depends of the ionic rays of different cations that exit into the network, have an effect on crystalline parameters and, consequently, on the density. In order to explain the defect structure of solid solutions synthesized in the ternary system Li2O–Ta2O5–(WO3)2 in a vicinity of LiTaO3,, we have shown a convergence between theoretical and experimental results by the application of our theoretical approach combined with the new proposed vacancy models. We conclude that the new vacancy models are able to describe the defect structure and the substitution mechanism in each solid solutions of WO3-doped lithium tantalate.

Experimental and theoretical study of the density of Cu-doped LiTaO3

In this work, we have investigated experimentally and theoretically, the evolution of a density of solid solutions synthetised in the vicinity of LiTaO3 in the ternary system Li2O–Ta2O5–(CuO)2 with a rate of % Cu and by two modes of cooling (slow and rapid cooling), for different solid solutions synthetised. We have realized that the mechanisms of non-stoichiometry for different phases at Cu2+ are sensitive to the cooling modes. In order to study by our theoretical approach, the correlation of the evolutions of density with defects structure of Cu-doped LiTaO3, we have proposed vacancy models that can explain the mechanism of substitution. The correlation of the density evolution with defects structure of Cu-doped LiTaO3, is investigated by using the theoretical approach which combined with proposed vacancy models in order to explain the substitution mechanism. The analytical modeling reproduce experimental measurements specifying the nature of substitution required.

Study of Electrical Conductivity in WO3-doped Nonstoichiometric LiTaO3

The results of experimental and analytical studies of the electrical conductivity for different solid solutions synthesized in a vicinity of LiTaO3 in the ternary system Li2O–Ta2O5–(WO3)2 are presented. It is shown that the electrical conductivity increases linearly with the Curie temperature. The experimental conductivity between 200 and 700 ºC was measured using an LCR bridge HP4192A on ceramics sintered at 1250 ºC. Within the theoretical approach to the defect structure analysis combined with our proposed vacancy models, the theoretical results are in a good agreement with the experimental data.

Subsolidus phase relations and the crystallization region of LiNbO 3 in the system Li 2O–B 2O 3–Nb 2O 5

Subsolidus phase relations in ternary system Li 2O–B 2O 3–Nb 2O 5 were determined and its phase diagram was constructed with the aid of XRD analysis. Eleven three-phase regions were identified in the subsolid phase diagram while no ternary compound was found. Meanwhile, four pseudo-binary systems, i.e., LiNbO 3–LiB 3O 5, LiNbO 3–Li 2B 4O 7, LiNbO 3–LiBO 2, and LiNbO 3–Li 3B 2O 4.5, were investigated and partial phase diagrams were determined on the LiNbO 3-rich side. Finally, the crystallization region of LiNbO 3 was identified in the ternary phase diagram. LiNbO 3 crystals can be grown by using a lithium borate as the flux below 1100 °C.

Ternary system Li 2O–K 2O–Nb 2O 5: Re-examination of the 30 mol% K 2O isopleth and growth of fully stoichiometric potassium lithium niobate single crystals by the micro-pulling down technique

Potassium lithium niobate (KLN) single crystals have attractive properties for non-linear optical applications based on frequency conversion of laser diodes in the blue range. Especially, fully stoichiometric K 3Li 2Nb 5O 15 crystals would be capable of doubling a laser light in the near UV range. Using powder X-ray diffraction and DSC experiments, we have re-investigated the 30 mol% K 2O isopleth of the ternary system Li 2O–K 2O–Nb 2O 5 in order to explore the possibility of a limited existence field for this phase. From our results, it was shown that the stoichiometric KLN phase exists between 970 and 1040 °C, temperature at which it undergoes a non-congruent melting. From this conclusion, compositionally homogeneous a-axis oriented single crystals fibers of stoichiometric K 3Li 2Nb 5O 15 were successfully grown by the micro-pulling down technique with pulling rates in the range 0.3–0.7 mm min −1. The crystal length was between 10 and 120 mm for an apparent diameter near 500 μm. The fibers, characterized by optical microscopy, X-ray diffraction and Raman spectroscopy, appeared free of macro-defects and of good quality and their stoichiometric composition was also confirmed.

Ternary System Li2O—K2O—Nb2O5. Part 1. Phase Equilibria Around the Lithium Niobate Existence Field.

ChemInformVolume 36, Issue 13 Physical Inorganic Chemistry Ternary System Li2O—K2O—Nb2O5. Part 1. Phase Equilibria Around the Lithium Niobate Existence Field. M. Cochez, M. Cochez Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorM. Ferriol, M. Ferriol Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorL. Poeppl, L. Poeppl Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorK. Polgar, K. Polgar Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorA. Peter, A. Peter Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this author M. Cochez, M. Cochez Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorM. Ferriol, M. Ferriol Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorL. Poeppl, L. Poeppl Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorK. Polgar, K. Polgar Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this authorA. Peter, A. Peter Lab. Chim. Appl., Univ. Metz, F-57500 Saint-Avold, Fr.Search for more papers by this author First published: 02 March 2005 https://doi.org/10.1002/chin.200513017AboutPDF 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. Volume36, Issue13March 29, 2005 RelatedInformation

Ternary system Li 2O–K 2O–Nb 2O 5: Part I: Phase equilibria around the lithium niobate existence field

In order to optimize the growth conditions of stoichiometric lithium niobate from K 2O–Li 2O–Nb 2O 5 fluxes, the limits of its crystallization field were determined by investigating phase equilibria in the ternary system Li 2O–K 2O–Nb 2O 5. For this purpose, suitable parts of four vertical sections were studied using DSC experiments and X-ray powder diffraction allowed to identify all the solid phases involved. The lithium niobate liquidus surface is delimited by four monovariant lines: Liq + Li 3NbO 4 + LiNbO 3, Liq + KNbO 3 + LiNbO 3, Liq + KLN solid solution + LiNbO 3 and Liq + LiNb 3O 8 + LiNbO 3. In the region investigated, three ternary invariant reactions were found. The first < LiNb O 3 > + < KNb O 3 > ⇄ < β -L i 3 Nb O 4 > + < KLN solid solution > is a quasi-peritectoid reaction occurring at 966 °C, the second is the eutectic reaction at 997 °C: Liq ⇄ < β -L i 3 Nb O 4 > + < KNb O 3 > + < LiNb O 3 > and the last one is the quasi-peritectic reaction: Liq + < KLN solid solution > ⇄ < KNb O 3 > + < LiNb O 3 > at about 1050–1055 °C.

Ternary system Li 2O–K 2O–Nb 2O 5: Part II: Growth of stoichiometric lithium niobate

Growth conditions of stoichiometric or near-stoichiometric lithium niobate (sLN) from K 2O containing fluxes have been studied by investigating phase equilibria in the ternary system Li 2O–K 2O–Nb 2O 5. The crystallization area of LiNbO 3 was confirmed by growth experiments on the g1 (LiNbO 3–K 2O), g2 (LiNbO 3–ternary eutectic liquid ( E t: 45.0 ± 1.5 mol% Nb 2O 5, 26.0 ± 1.5 mol% K 2O and 29.0 ± 1.5 mol% Li 2O)) and g3 (LiNbO 3–KNbO 3) joins. The yield and the composition of LiNbO 3 single crystals were tested for a wide range of starting compositions. From these experiments, the starting compositions leading to stoichiometric lithium niobate have been determined.

Concentration and temperature regions of phase crystallization in the system Li 2O–Al 2O 3–WO 3

The concentration and temperature regions of formation of crystals from different phases of the ternary system Li 2O–Al 2O 3–WO 3 have been determined using the results on spontaneous crystallization in various high-temperature solutions of this system. It has been established that crystallization proceeds with no measurable evaporation of WO 3 when the temperature is below 1150 °C. For that reason, solution compositions varying within the limits of 10–40 mol.% for Li 2O, 2–20 mol.% for Al 2O 3 and 57–80 mol.% for WO 3 have been used. In these limits the crystallization regions of Li 2W 2O 7, WO 3, Al 2(WO 4) 3 and of the low- and high-temperature modification of LiAlW 2O 8 have been determined. The crystals isolated from the above five regions have been characterized by X-ray diffraction, thermal, atomic absorption and X-ray fluorescence analyses. The results obtained indicate the possibility of developing convenient methods for growing single crystals of the aluminum-containing phases, to be used, upon suitable doping with transition metal ions, as active media for tunable solid state lasers. The growth of Al 2(WO 4) 3 single crystals from a high-temperature solution in a solvent with the eutectic composition of Li 2O:WO 3=41:59 (molar ratio) has been demonstrated.

The Ternary System Li2O–Al2O3–B2O3: Compounds and Phase Relations

The ternary system Li2O–Al2O3–B2O3 is reinvestigated with solid-state reaction and X-ray powder diffraction technique to clarify some long-standing uncertainties. The phase relations are constructed based on the phase identifications of 51 ternary samples. Six ternary compounds, Li2AlB5O10, LiAlB2O5, Li3AlB2O6, Li2AlBO4, LiAl7B4O17 and a compound with a composition close to 0.66Li2O·0.06Al2O3·0.28B2O3, are observed or confirmed in this system, and the thermal stability of these ternary compounds is also discussed on the basis of DTA experimental results.

The Ternary System Li2O – Sb2O5 – CuO

ABSTRACTSubsolidus compatibility relations in the ternary system Li2O – Sb2O5 – CuO have been determined. One new copper-rich phase, LiCu4SbO7, W, and one new solid solution series, Li1-xSb1-xCu3xO3, over the composition range 0 &lt; × ≤ 0.077 have been prepared. Eight triangles of compatibility were determined at (approximately) 1000 °C.

Potassium lithium niobate: single-phase domain boundary in the 30 mol% K 2O isopleth of the ternary system Li 2O–K 2O–Nb 2O 5 and characterization of single-crystal fibers

K 3Li 2−xNb 5+xO 15+2x (x < 0.5, KLN) crystals are very promising for blue-light second harmonic generation, and their growth conditions are important to know. For this purpose, the limit of the solid solution range in the 30 mol% K 2O isopleth of the ternary system Li 2O–K 2O–Nb 2O 5, to which KLN crystals belong, was investigated by powder X-ray diffraction (XRD). Several crystals with different compositions x were also pulled by the LHPG (laser-heated pedestal growth) technique and characterized by energy-dispersive system (EDS) microprobe analysis, absorption spectra measurements, phase matching studies, and Raman microspectroscopy.

Growth and characterization of MgO-doped single-crystal fibers of lithium niobate in relation to high temperature phase equilibria in the ternary system Li2ONb2O5MgO

The growth of MgO-doped single-crystal fibers of LiNbO 3 by the laser heated pedestal growth method was investigated as a function of the MgO content in the feed rods. The fibers were characterized by X-ray diffraction, optical microscopy and EDX microprobe analysis. The results are discussed in relation to phase equilibria in the ternary system Li 2 ONb 2 O 5 MgO. Yb 2 O 3 and MgO co-doped fibers were also grown and spectroscopically analyzed to study the influence of the MgO content on the luminescence of Yb 3+ ions with the aim of producing a self-doubling laser material.

Investigation of nonstoichiometry and ferroelectric properties in the ternary system Li 2OTa 2O 5(WO 3) 2 at 1250°C under atmospheric pressure

X-ray crystallographic studies conducted at atmospheric pressure have allowed determination of the limits of solid solutions with LiTaO 3 structure in the ternary system Li 2OTa 2O 5(WO 3) 2. Stoichiometry analysis has shown that the prevailing type of nonstoichiometry of these phases is simultaneous cationic and anionic deficits. Dielectric measurements carried out on the ceramic samples showed a decrease in the ferroelectric Curie temperature as the composition deviates from that of pure LiTaO 3.

Flux growth of LiNdP 4O 12 single crystals

LiNdP 4O 12 single crystals were grown by slow-cooling a Li 2OP 2O 5 flux. Crystal morphology and macroscopic crystal quality depend on the solution composition in the ternary system Li 2ONd 2O 3P 2O 5. Under the favorable growth conditions, platy crystals of 15 × 10 × 1 mm 3 were obtained.