Preparation and Characterization of Highly-Dispersed and Highly-Crystalline Barium Titanate Nanoparticles

2013 ◽  
Vol 566 ◽  
pp. 273-276
Author(s):  
Tatsuya Kita ◽  
Takahiro Takei ◽  
Nobuhiro Kumada ◽  
Kouichi Nakashima ◽  
Ichiro Fujii ◽  
...  

Highly dispersed barium titanate (BaTiO3, BT) nanoparticles were prepared by the new 2-step thermal decomposition method of barium titanyl oxalate of 30 nm in size. The nanoparticles were heated at 450 °C for 5 hours in air to yield intermediate product: Ba2Ti2O5CO3. Highly dispersed BaTiO3 nanoparticles were prepared by rotationally stirring it at the reduced pressure of 0.2 Pa at various temperatures between 800 °C and 900 °C. The particle size and morphology of the BaTiO3 nanoparticles were investigated by X-ray diffraction and scanning electron microscopy. These measurements showed that the BT nanoparticles were highly dispersed and well-crystallized.

2014 ◽  
Vol 602-603 ◽  
pp. 19-22 ◽  
Author(s):  
Lin Qiang Gao ◽  
Hai Yan Chen ◽  
Zhen Wang ◽  
Xin Zou

Nanoscale LiTaO3 powders with perovskite structure were synthesized using the solvothermal technique with glycol as solvent at 240°C for 12h. The powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD was used to elucidate room temperature structures using Rietveld refinement. The powders were pure single pervoskite phase with high crystallinity. FESEM and TEM were used to determine particle size and morphology. The average LiTaO3 grain size was estimated to be < 200nm, and TEM images indicated that LiTaO3 particles had a brick-like morphology. In addition, the effect of the temperature on the LiTaO3 power characterisitics was also detailed studied.


2004 ◽  
Vol 821 ◽  
Author(s):  
Mohammad Mujahid ◽  
Jie Zhu

AbstractNanostructured alloys have great potential as soft magnetic materials. In particular, nanocrystalline Fe-Co based alloys are believed to be good candidates for imparting improved magnetic behavior in terms of higher permeability, lower coercivity, reduced hysteresis losses and higher Curie temperatures. In the present work, Fe-50at.%Co alloy powders have been prepared using mechanical alloying (MA) in a planetary ball mill under controlled environment. The particle size and morphology of MA powders was investigated using scanning electron microscopy. The crystal size and internal strain was measured using X-ray diffraction. It has been shown that the crystal size could be reduced down to less than 15 nm in these alloys. Finally, the influence of grain size and internal strain on the magnetic properties has been discussed.


2009 ◽  
Vol 421-422 ◽  
pp. 506-509 ◽  
Author(s):  
Shuhei Kondo ◽  
Chikako Moriyoshi ◽  
Yoshihiro Kuroiwa ◽  
Satoshi Wada

Barium titanate (BaTiO3) nanoparticles were prepared by two-step thermal decomposition method of barium titanyl oxalate nanoparticles with a size of 30 nm. The BaTiO3 particle sizes were changed from 12.3 to 142 nm by control of temperature at 2nd step. The X-ray diffraction (XRD) measurement revealed that a clear splitting of 002 and 200 planes was observed over 40 nm, and the c/a ratio of 1.0089 was obtained for the BaTiO3 nanoparticles with a size of 62.3 nm. This high c/a ratio in the BaTiO3 nanoparticles suggested that its mesoscopic particle structure was composed of very thin surface cubic layer below 5 nm. Thus, synchrotron XRD data were analyzed using a “two layers” model and a “three layers” model. The Rietveld analysis using the three layers model resulted in the particle structure with a cubic layer thickness of 2.5 nm and structure gradient layer thickness of 7.5 nm. Finally, the dielectric constant of these BaTiO3 nanoparticles with thin surface cubic layer was measured at room temperature, and the maximum dielectric constant over 30,000 was obtained at the nanoparticles with a size of 83.6 nm.


2015 ◽  
Vol 14 (04) ◽  
pp. 1550013 ◽  
Author(s):  
Urvisha Tarpara ◽  
Poorvesh Vyas ◽  
Mihir J. Joshi

Calcium tartrate finds various applications. In the present study, calcium tartrate nanoparticles were synthesized by wet chemical method using surfactant mediated approach. The powder XRD pattern revealed the typical broadening of peaks indicating the nanostructured nature. The average crystallite size was calculated by applying the Scherrer's formula to powder XRD pattern and was found in the range of 22.8–23.9 nm. The particle size and morphology of the synthesized nanoparticles was confirmed by using transmission electron microscopy (TEM). FTIR spectroscopy was used to confirm the presence of various functional groups. From TGA, it was found that calcium tartrate nanoparticles remained stable up to 120°C and were having two water molecules associated with them. The results are compared with the bulk crystalline materials available in the literature.


2011 ◽  
Vol 178-179 ◽  
pp. 43-49 ◽  
Author(s):  
Peter Zaumseil ◽  
Yuji Yamamoto ◽  
Joachim Bauer ◽  
Markus Andreas Schubert ◽  
Jana Matejova ◽  
...  

Selective epitaxial growth of germanium (Ge) on nano-structured Si(001) wafers is studied to evaluate the applicability of the nano-heteroepitaxy (NHE) approach on Ge-Si system. Based on a gate spacer technology established in advanced silicon microelectronics periodic arrays of nano-scaled Si islands are prepared, where Ge is deposited on top by reduced pressure CVD. The spacing of these structures is 360 nm. The structural perfection of the deposited Ge is investigated by transmission electron microscopy and X-ray diffraction. It is found that SiO2used as masking material is responsible for the suppression of the desired strain partitioning effect according to NHE. Even for 10 nm oxide thickness, the lattice of Ge layers deposited on Si nano-islands relaxes completely by generation of misfit dislocations at the interface. The occurrence of additional structural defects like stacking faults and micro twins can be controlled by suited growth conditions.


2012 ◽  
Vol 1481 ◽  
pp. 45-52
Author(s):  
A. Medina ◽  
L. Béjar ◽  
G. Herrera-Pérez

ABSTRACTMagnesium hydroxide (Mg(OH)2) nanoparticles were synthesized by chemical precipitation synthesis method. The influence of the nano-sized Mg(OH)2 on the structural modification was evaluated. The formation of Mg(OH)2 crystals were evaluated by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The particle size and morphology of Mg(OH)2was confirmed by high resolution transmission electron microscopy (HRTEM). The crystalline structure of nanoparticles was characterized by fast Fourier transform (FFT) and X-Ray diffraction (XRD), like analytical tools.


2018 ◽  
Vol 280 ◽  
pp. 102-108
Author(s):  
Tinesha Selvaraj ◽  
Johar Banjuraizah ◽  
S.F. Khor ◽  
M.N. Mohd Zainol

The sintering behaviour of low cost 8 mol% yttria stabilized zirconia powders has been studied. The effect of sintering holding time of the sintered granulated and milled 8YSZ were determined using density measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The elemental composition, particle size and morphology of the as-received 8YSZ powder and proceed for milling was investigated. 48 hours of ball milling on granulated 8YSZ resulted rises in specific surface area and sintered at 1550°C with the various period of time (4, 5, 6 and 7 hours). The milled 8YSZ sample with 5h sintering holding period coded as F5, sintering activity improved and the relative density came up to 98.3%. But then, granulated 8YSZ achieved only 62.7% with 5 hours holding time. Crystal structure analysis for milled 8YSZ powder consists of 59.6% of cubic ZrO2 phase, 40.1% of tetragonal ZrO2 and 0.3% of monoclinic ZrO2. Meanwhile, granulated 8YSZ indicated low content in cubic ZrO2 but high amount in monoclinic ZrO2 phase. In brief, low cost 8YSZ reached higher densification of 98% successfully.


1990 ◽  
Vol 73 (11) ◽  
pp. 3422-3427 ◽  
Author(s):  
Fu-Su Yen ◽  
Chen T. Chang ◽  
Yen-Hwei Chang

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