Synthesis of Single-Crystalline Plate-Shaped K0.5Na0.5NbO3 Particles by Multi-Step Molten Salt Method

2012 ◽  
Vol 512-515 ◽  
pp. 1395-1398 ◽  
Author(s):  
Zhi Liu ◽  
Yue Ming Li ◽  
Zong Yang Shen ◽  
Zhu Mei Wang

In this study, single-crystalline plate-shaped KNN particles were successfully synthesized by a multi-step molten salt method (MMSM). First, precursor particles K4Nb6O17 (K4N6) with layer-structure was synthesized at 1050 °C in molten KCl-salt (MMSM-1) by starting materials of Nb2O5 and K2CO3. Second, plate-shaped KNN was synthesized at 1000 °C in molten KCl-NaCl-salt (MMSM-2) from K4N6 particles and K2CO3 powders. X-ray diffraction (XRD) analysis revealed that the crystallographic {010} plane of K4N6 was converted into the pseudo-cubic {001} plane of KNN. SEM images showed that MMSM-synthesized KNN particles preserved the shape of K4N6 precursor particles, and had a thickness of about 3 ~ 5 μm, a width of 10 ~ 15 μm and a length of 15 ~ 20 μm. EDX spectrum proved that the K:Na mole ratio was 0.6:0.4. These plate-shaped KNN particles were very promising templates to fabricating textured KNN-based ceramics.

2015 ◽  
Vol 830-831 ◽  
pp. 683-686 ◽  
Author(s):  
Megha Tyagi ◽  
B. Vishwanadh ◽  
Subir Kumar Ghosh ◽  
R. Tewari

The main aim of the present work is to develop an oxidation resistant Nb-Si coating on Nb alloys. For this purpose electroless molten salt - method was used, where a selective reaction occurs between NaCl–KCl–NaF–Na2SiF6and the Si powder. Due to this reaction, oxidation resistant Nb-Si phases forms on the surface of substrate. This paper reports the thickness variation of Nb-Si coating as a function of deposition time. The surface morphology was studied by using scanning electron microscopy (SEM). The various Nb-Si based phases formed on the Nb substrate have been identified using X-ray diffraction (XRD) analysis, supplemented with energy dispersive X-ray spectroscopy results. Based on these results mechanism of silicide coating on Nb alloys has been discussed in detail.


2013 ◽  
Vol 873 ◽  
pp. 24-29 ◽  
Author(s):  
Jing Feng ◽  
Tian Di Liu ◽  
Yan Chen ◽  
Yu Ting Wang ◽  
Yue Ming Ren ◽  
...  

Cu doped NiCuZn ferrite Ni0.4-xCuxZn0.6Fe2O4(x=0.16~0.28) have been prepared by the solid-molten salt method using NaCl as flux. The structure and properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) techniques. It is found that addition of Cu2+results in the particles size growing up because of the tend of crystal structure to be a normal Zn ferrite.TheMsvalues of NCZF are decrease gradually with increasing of Cu content. Curie temperature (Tc) increases with Cu2+content in the range of x<0.20, and then decreasing rapidly. This can be ascribed to that the lower magnetization moment Cu2+ion amount of B-site increasing leads to weaker super-exchange effect.


2010 ◽  
Vol 434-435 ◽  
pp. 240-243 ◽  
Author(s):  
Hai Feng Li ◽  
Rong Zhou Gong ◽  
Hao Luo ◽  
Jun Zhou ◽  
Li Ren Fan ◽  
...  

M-type hexaferrites Ba(TiMn)xFe12-2xO19 (x=0 to 2) powders were synthesized by molten salt method. X-ray diffraction, scanning electron microscope and vibrating sample magnetometer were used to analyze the structures and electromagnetic properties. The results showed that, the magnetoplumbite structures for all samples were formed. Magnetic hysteresis loop measurements of the Ba(TiMn)xFe12-2xO19, exhibitted that the saturation magnetization (Ms), the remanent magnetization (Mr) and the coercitivity (Hc) of compounds depended strongly on the chemical composition of materials. The maxium values of Ms (52.68emu/g) and Mr (32.89emu/g) of the compounds were found at x=0.5; however, the values of Hc and the areas of magnetic hysteresis loop of compounds decreased with increasing the value of x. The Ba(TiMn)1.5Fe9O19/paraffin wax composites containing 40vol% of doped barium ferrite exhibitted good absorption performances in the frequency range of 2–14 GHz.


2013 ◽  
Vol 690-693 ◽  
pp. 981-984
Author(s):  
Guang Xin Fan ◽  
Hui Lian Li ◽  
Shu Pu Dai ◽  
Chuan Xiang Zhang ◽  
Xue Mao Guan ◽  
...  

In this paper, LiOH·H2O and Li2CO3, which were widely used in industry and (Mn0.533Co0.233Ni0.233) (OH)2prepared by ourselves selected as starting materials, series materials of lithium-rich layered material Li [Li0.2Mn0.44Ni0.18Co0.18]O2were obtained by a molten salt method. Their structures and properties of the materials were investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and constant current charge/discharge methods. The effects of different LiOH and Li2CO3molar ratios on the Li [Li0.2Mn0.44Ni0.18Co0.18]O2structures and properties were characterized. The results of the experiments indicate that The structures of the material such as crystal structure, the specific area, particle size distribution, tap densities were controlled by adjusting the proportion of the two lithium sources. Forthermore , when the molar ratio of LiOH and Li2CO3was 3:7, the maximum discharge capacity (214.77 mAhg-1) of the cathode was obtained.


2016 ◽  
Vol 697 ◽  
pp. 399-403 ◽  
Author(s):  
Xian Gong Deng ◽  
Jun Kai Wang ◽  
Hai Jun Zhang ◽  
Jiang Hao Liu ◽  
Shao Wei Zhang

Magnesium aluminate spinel (MgAl2O4) porous ceramics were in-situ synthesized by heating the mixture of Al2O3 and MgCO3 with MgCl2 salt at 1400~1600 °C for 3 h, and then characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The morphology of as-prepared MgAl2O4 porous ceramics was dependent on the addition of MgCl2, and it indicated that the MgCl2 molten salt not only acted as a template for pore formation of the porous ceramics, but also provided a liquid environment for the synthesis of MgAl2O4.


2016 ◽  
Vol 16 (4) ◽  
pp. 3857-3860 ◽  
Author(s):  
Siling Guo ◽  
Chunyan Cao ◽  
Renping Cao

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.


2009 ◽  
Vol 79-82 ◽  
pp. 2071-2074 ◽  
Author(s):  
Hai Feng Li ◽  
Rong Zhou Gong ◽  
Xian Wang ◽  
Li Ren Fan ◽  
Gang He ◽  
...  

M-type hexaferrites Ba(ZnZr)xFe12-2xO19 (x=0, 0.5, 1.0, 1.5) powders, have been synthesized by molten salt method, where x varies from 0 to 1.5 in steps of 0.5. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer(VSM) were used to analyze the structures and magnetic properties. The results showed that, the magnetoplumbite structures for all samples calcining at 1100°C have been formed. The magnetic hysteresis loop measurements of the hexagonal ferrites powders showed that the saturation magnetization (Ms), the remanent magnetization (Mr), and the coercitivity (Hc) of ferrites depend strongly on the chemical compositions of materials. The data showed that the max Hc was obtained when substitution of x=1.0 (Hc=63.9 Oe), while the best Ms was obtained when substitution of x=0.5 (Ms=54.02 emu/g). Zn and Zr substitutions greatly modified the magnetic properties of BaM hexaferrite.


2011 ◽  
Vol 311-313 ◽  
pp. 545-548 ◽  
Author(s):  
Yu Jiang Wang ◽  
Yong Gang Wang

NiWO4 nanoparticles were successfully synthesized by a molten salt method at 270°C. The as-prepared powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and exhibited a pure phase NiWO4 with about 50 nm in particle size and uniform nearly-spherical particle shape.


2012 ◽  
Vol 472-475 ◽  
pp. 2452-2457 ◽  
Author(s):  
Xiao Hui Jiang ◽  
Jun Feng Ma ◽  
Jie Cheng ◽  
Jing Rui Fang ◽  
Yong Sun

Cadmium molybdate (CdMoO4) nanoparticles, cube-like crystallites and octahedral microparticles have been successfully synthesized by a molten salt method at 270°C. The structure, morphology and luminescent property of the resultant powders were characterized by X-ray diffraction (XRD), transmission electron microcopy (TEM), scanning electron microcopy (SEM), and photoluminescence (PL), respectively. The resultant samples are a pure phase of CdMoO4 and without any impurities. PL spectra results show that the optical properties of CdMoO4 particles are strongly relied on their morphologies.


2012 ◽  
Vol 182-183 ◽  
pp. 52-56
Author(s):  
Jun Que Lu ◽  
Xiu Feng Wang ◽  
Hong Tao Jiang

Pure Bi12SiO20powder was successfully prepared by a molten salt method using Bi2O3and SiO2as raw materials and using KCl-K2CO3as flux at 635°C with the heating rate of 5°Cmin-1. The phase composition and microstructure of these products were analyzed by X-ray diffraction and scanning electron microscopy, and the effects of the processing parameters, such as the ratio of Bi2O3/SiO2, calciniation temperature, isothermal time and relative amount of salt, on the composition and particle size were investigated. The results indicated that regardless of changing the ratio of Bi2O3/SiO2, calciniation temperature, isothermal time or relative amount of salt the reaction only yielded Bi12SiO20without Bi2SiO5and Bi4Si3O12. Henceforth, KCl-K2CO3molten salts may be considered as an ideal reaction medium to synthesize pure phase of Bi12SiO20. The particle size of Bi12SiO20phase can be determined by changing the temperature, isothermal time and relative amount of salt.


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