Antisite defect elimination through Mg doping in stoichiometric lithium tantalate powder synthesizedviaa wet-chemical spray-drying method

2015 ◽  
Vol 48 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Dehui Sun ◽  
Xueliang Kang ◽  
Qian Yu ◽  
Kun Cui ◽  
Xiaoyong Qin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Spray Drying ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Drying Method ◽  
Reaction Method ◽  
Mg Doping ◽  
Chemical Spray ◽  
Wet Chemical

MgO-doped stoichiometric LiTaO3(MgO:SLT) is one of the most promising nonlinear materials. However, its industrial application is limited by the poor optical quality caused by the nonhomogeneous distribution of magnesium. Herein, an MgO:SLT polycrystalline powder was synthesized with a homogenous magnesium distribution by a wet-chemical spray-drying method. A comparative investigation of the coordination state of Ta ions in MgO:SLT powders synthesized by this method and by a conventional solid-state reaction method was performed by X-ray photoelectron spectroscopy. It is proved that the Ta–Li antisite was completely eliminated as a result of the homogeneous Mg doping in the SLT lattice using the wet-chemical spray-drying method. However, for MgO:LT powder produced by the solid-state reaction method, element analysis after acid treatment shows that some Mg ions did not enter the LT lattice after high-temperature calcination. Also, scanning electron microscopy and transmission electron microscopy energy dispersive spectroscopy verified that some MgO particles still exist in the as-synthesized MgO:LT powder. This synthesis method can be used for mass production of high-quality polycrystalline powders for doped crystal growth and some other doped oxide powder products with high melt point.

Tribological and electrical behavior of Cu-based composites with addition of Ti-doped NbSe2 nanoplatelets

2018 ◽  
Vol 70 (3) ◽  
pp. 560-567 ◽  
Author(s):  
Jian Feng Li ◽  
Qin Shi ◽  
HeJun Zhu ◽  
ChenYu Huang ◽  
Shuai Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Friction Coefficient ◽  
Electrical Properties ◽  
Tribological Properties ◽  
Solid State Reaction ◽  
Electrical Contact ◽  
Solid State Reaction Method ◽  
Content Type ◽  
Reaction Method

Purpose This paper aims to clarify the size and morphology of transition metal dichalcogenides has an impact on lubrication performance of Cu-based composites. This study is intended to show that Cu-based electrical contact materials containing Nb0.91Ti0.09Se2 have better electrical and tribological properties than those containing NbSe2. The tribological properties of Cu-based with different Ti-dopped NbSe2 content were also discussed. Design/methodology/approach The NbSe2 and Nb0.91Ti0.09Se2 particles were fabricated by thermal solid state reaction method. The powder metallurgy technique was used to fabricate composites with varying Nb0.91Ti0.09Se2 mass fraction. The phase composition of Cu-based composites was identified by X-ray diffraction, and the morphology of NbSe2/Nb0.91Ti0.09Se2 and the worn surface of composites were characterized by scanning electron microscopy and transmission electron microscopy. In addition, the tribological properties of composites were appraised using a ball-on-disk multi-functional tribometer. The data of friction coefficient and resistivity were analyzed and the corresponding conclusion was drawn. Findings In comparison with the pure copper, Cu-based composites containing Nb0.91Ti0.09Se2/NbSe2 had a lower friction coefficient, illustrating the Nb0.91Ti0.09Se2 with nano-size particles prepared in this work is a perfect choice for the fabrication of excellent electrical contact composites. Compared to composites with NbSe2, composites containing Nb0.91Ti0.09Se2 have better tribological and electrical properties. Research limitations/implications Because of the use of thermal solid state reaction method, the size of NbSe2 and Nb0.91Ti0.09Se2 is relatively large. Therefore, the fabrication of finer particles of Nb0.91Ti0.09Se2 is encouraged. Originality/value In this paper, the authors discuss the tribological and electrical properties of Cu-based composites, and the value of optimum obtained as Nb0.91Ti0.09Se2 content is 15 Wt.%.

scholarly journals Effect of Calcination Temperature on the Physical Properties of Layered LiNiO2 Prepared by Solid-State Reaction Method

2016 ◽  
Vol 67 ◽  
pp. 31-35 ◽  
Author(s):  
Nandigam Murali ◽  
Jampana Madhuri Sailaja ◽  
Tewodros Aregai ◽  
S.J. Margarette ◽  
V. Veeraiah
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Field Effect ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Ft Ir ◽  
Scanning Electron

A layered structure compound LiNiO2 material is synthesized by the solid-state reaction method under air atmosphere in the temperature range from 750 °C to 850 °C using Li2CO3 and NiO as the starting materials for 20 hours. The physical properties of the synthesized powder are investigated by X-ray diffraction (XRD), Field effect scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopic (FT-IR) techniques. The results of XRD patterns possessed the α-NaFeO2 structure of the rhombohedral system (space group, ) with no evidence of any impurities. The morphological features of the powders are characterized by field effect scanning electron microscopy (FESEM). The particles of LiNiO2 powder are generally in the form of a smoothly edged polyhedron and their average grain size is approximately 2 - 3 μm. The FT-IR spectroscopic data of LiNiO2 reveal the structure of the oxide lattice constituted by LiO6 and NiO6 octahedra. In general, from this study, we conclude that the LiNiO2 synthesized by solid state reaction method at different temperatures to increase in the sintering temperature. The lattice constant is increased, while the sintering temperature is increased. The maximum and minimum intensity ratios of XRD spectra shows that the optimum calcination condition is 800°C for 20 h. At 750-850°C, the particle size distribution is in the range of 2 - 3 μm.

MgO Nanostructured Materials Obtained Via the Solid-State Reaction Method

2014 ◽  
Vol 895 ◽  
pp. 347-350
Author(s):  
Nor Fadilah Chayed ◽  
Norlida Kamarulzaman ◽  
Nurhanna Badar ◽  
Rusdi Roshidah ◽  
Norashikin Kamarudin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Magnesium Acetate ◽  
Synthesis Methods ◽  
Acetate Tetrahydrate ◽  
Conventional Solid State Reaction ◽  
Simple Method ◽  
Reaction Method

Recently, several synthesis methods have been reported for producing magnesium oxide (MgO) nanostructures such as sol-gel, combustion, thermal evaporation, chemical precipitation, etc. This work describes a simple method to synthesize MgO nanostructures via a conventional solid-state reaction method using magnesium acetate tetrahydrate as a starting material. Magnesium acetate tetrahydrate was directly annealed at a temperature of 600 °C and 800 °C for 24 h. The X-Ray Diffraction (XRD) revealed that the annealed samples were pure while Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) showed different morphologies of MgO. From the results, it is found that TEM may reveal information that cannot be observed in the SEM micrographs.

Fabrication and Properties of Zinc Silicate Phosphors through Solid State Reaction

2010 ◽  
Vol 160-162 ◽  
pp. 594-598
Author(s):  
Guo Jian Jiang ◽  
Jia Yue Xu ◽  
Hui Shen ◽  
Yan Zhang ◽  
Lin He Xu ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Emission Peak ◽  
Zinc Silicate ◽  
Red Phosphor ◽  
Reaction Method ◽  
Long Afterglow ◽  
Luminescent Mechanism ◽  
Silicate Phosphors

Zinc silicate-based (Zn2SiO4:Eu3+) long afterglow phosphors were produced by solid state reaction method. The effects of borax and Eu2O3 additive on the properties of fabricated products have been studied. The results show that, there is not much difference in phase compositions within the borax additive amount; however, their SEM morphologies are different. Borax additive can increase the grain size of the product. Some sintering phenomena could be observed in the sample with Eu2O3 addition. The fluorescence spectroscopy results indicate that, the emission peak of the sample with Eu3+ additive located at 612nm, which may be a good candidate for red phosphor applications. The luminescent mechanism of Zn2SiO4:Eu3+ is also discussed.

Luminescence properties of dysprosium doped calcium magnesium silicate phosphor by solid state reaction method

2015 ◽  
Vol 649 ◽  
pp. 1329-1338 ◽  
Author(s):  
Ishwar Prasad Sahu ◽  
Priya Chandrakar ◽  
R.N. Baghel ◽  
D.P. Bisen ◽  
Nameeta Brahme ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Magnesium Silicate ◽  
Solid State Reaction Method ◽  
Luminescence Properties ◽  
Reaction Method ◽  
Silicate Phosphor ◽  
Calcium Magnesium
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