Wet chemical synthesis of pure LiNbO3 powders from simple niobium oxide Nb2O5

Liu, Meinan; Xue, Dongfeng; Luo, Chao

doi:10.1016/j.jallcom.2006.02.019

Cited by 31 publications

(15 citation statements)

References 17 publications

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“…Liu et al [17] reported three absorption modes at 693, 646 and 437 cm -1 for LiNbO 3 were obtained by hydrothermal method. In our work, there were three absorption peaks at 666, 635 and 439 cm -1 , which were in agreement with literature values [10,12]. It can be concluded that the LiNbO 3 samples synthesized between 500 and 700 °C are high-quality without organic and CO 3 2-impurities.…”

Section: Resultssupporting

confidence: 91%

Preparation of nanocrystalline lithium niobate powders at low temperature

Jiang²,

Gong

et al. 2010

Cryst. Res. Technol.

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Key words lithium niobate powders, ammonium niobium oxalate, alternative solid-state method.A facile route to prepare lithium niobate (LiNbO 3 ) powders was proposed by an alternative solid-state method. Stoichiometric Li 2 C 2 O 4 and ammonium niobium oxalate were mixed with small amounts of water and then dried at room temperature. It was demonstrated that Li[NbO(C 2 O 4 ) 2 ]·nH 2 O intermediate was produced by an ion-exchange reaction. Pure LiNbO 3 powders were successfully synthesized by heating the intermediate at 500, 600 and 700 °C for 3 h. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, UV-Vis diffuse reflectance (UV-Vis) spectroscopy and thermogravimetric (TG) analysis were used to characterize the precursor compound and as-prepared samples. XRD results reveal that all the products are identified as hexagonal structure with high relative crystallinity (>87%). The particle size is found to be about 40 nm for the mixture calcined at 500 °C according to XRD data, which is in good agreement with SEM data. The as-prepared LiNbO 3 powders by this method are high quality according to FTIR spectra. (Li 0.996 Nb 0.005 )Nb 0.999 O 3 phase was formed when the calcination temperature was raised to 800 °C.

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Section: Resultssupporting

confidence: 91%

Preparation of nanocrystalline lithium niobate powders at low temperature

Jiang²,

Gong

et al. 2010

Cryst. Res. Technol.

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“…It will be soon shown that, for all the performed studies, unmistakable linear relationships happen to exist among these samples and their corresponding experimental parameters (related to the CC); a striking, very sensitive, deviation from these trends is observed for all samples out of this range, in some cases even under the consideration only of neighbor samples such as LN + 1%LiP and LN + 4%NbP. Lastly, besides the well-known difficulties to produce single-phase ST LN at temperatures used in solid-state reactions (T ≥ 1200 C) [32,33], much ambiguity can be found in the literature concerning deviation from stoichiometry in the formation of LNPws at calcination temperatures near T = 850 • C. While only one work is found to report no loss of Li after two 16-hour reaction periods at 1120 • C [34], other authors have observed the loss of Li at 600-800 • C within at least three different investigations [33,35,36]. However, these methods of synthesis are very different from each other, except for those in the works published in 2006 (Liu et al) [33] and 2008 (Liu et al) [36], which are aqueous soft-chemistry methods.…”

Section: Justification Of the Assumption Made In The X-ray Diffractiomentioning

confidence: 96%

Determination of the Chemical Composition of Lithium Niobate Powders

et al. 2019

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Existent methods for determining the composition of lithium niobate single crystals are mainly based on their variations due to changes in their electronic structure, which accounts for the fact that most of these methods rely on experimental techniques using light as the probe. Nevertheless, these methods used for single crystals fail in accurately predicting the chemical composition of lithium niobate powders due to strong scattering effects and randomness. In this work, an innovative method for determining the chemical composition of lithium niobate powders, based mainly on the probing of secondary thermodynamic phases by X-ray diffraction analysis and structure refinement, is employed. Its validation is supported by the characterization of several samples synthesized by the standard and inexpensive method of mechanosynthesis. Furthermore, new linear equations are proposed to accurately describe and determine the chemical composition of this type of powdered material. The composition can now be determined by using any of four standard characterization techniques: X-Ray Diffraction (XRD), Raman Spectroscopy (RS), UV-vis Diffuse Reflectance (DR), and Differential Thermal Analysis (DTA). In the case of the existence of a previous equivalent description for single crystals, a brief analysis of the literature is made.

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“…In comparison, sol-gel method excels solid state reaction in improved homogeneity and precise compositional control at reduced tem- * Corresponding authors. peratures [9]. Low processing temperatures can prevent phase separation [10] and lithium loss, which is essential for the synthesis of LT powders.…”

Section: Introductionmentioning

confidence: 99%