Fabrication of Plate-Like Sr3Ti2O7 Particles Using Molten Salt Synthesis

2014 ◽  
Vol 1058 ◽  
pp. 15-19 ◽  
Author(s):  
Sheng Jie Yang ◽  
Feng Gao ◽  
Meng Jie Qin ◽  
Qing Qing Zhang ◽  
Xi Xi Huang

Plate-like Sr3Ti2O7powders with anisotropy were prepared by KCl molten salt synthesis (MSS) method, the effect of different SrCO3/TiO2ratio and calcination condition on the phase transition, particle size and morphology of powders were investigated. The results show that SrTiO3phase coexist with Sr3Ti2O7phase and SrTiO3is the main phase as the SrCO3/TiO2ratio is 1.15~1.25:1. Pure Sr3Ti2O7phase can be obtained as the SrCO3/TiO2ratio is 1.55~1.65:1. The aspect ratio of plate-like particles increases firstly and then decreases as the SrCO3/TiO2ratio increases. The sealed and unsealed condition has no influence on the phase structure of the powders. But the aspect ratio of unsealed particles is smaller than that of sealed particle. Finally, the formation mechanism for Sr3Ti2O7particles was discussed.

2014 ◽  
Vol 997 ◽  
pp. 428-432
Author(s):  
Qian Ying Zhang ◽  
Xun Geng

High-quality flaky α-Al2O3 powder with regular morphology, uniform size, larger diameter-thickness proportion and excellent dispersibility in water and free from agglomeration and staggered growth was obtained on the basis of molten salt synthesis method. The effects of experiment parameter on the particle size and morphology of flaky alumina powder were studied. The mechanism of morphology control was discussed.


2008 ◽  
Vol 368-372 ◽  
pp. 115-117 ◽  
Author(s):  
Ke Pi Chen ◽  
Yong He ◽  
Dong Yu Liu ◽  
Zong De Liu

CCTO powders were prepared by using molten salt method in the NaCl-KCl system. The effects of temperature and holding time on phase compositions, particle morphology and size have been investigated by X-ray diffraction, scanning electron microscope and laser particle size analyzer. Using CaCO3, CuO and TiO2 as starting materials, CCTO compound could be synthesized at any temperature from 800oC to 1000oC in the NaCl-KCl system. The average particle size increased obviously with the increasing of temperature above 850 oC. Holding time had great effect on grain size and morphology.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jing Shang ◽  
Ruonan Gao ◽  
Fu Su ◽  
Huaguang Wang ◽  
Dan Zhu

The complex rheology and the phase behavior of thermally sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have been investigated in both the swollen and collapsed states by using microrheology. To avoid the interactions between the tracer probes and the PNIPAM microgels, such as the adsorption or the depletion effect, the probes of silica (SiO2) particles have been grafted with PNIPAM chains (SiO2-PNIPAM) and characterized with Fourier transform infrared spectroscopy (FTIR). The successful preparation of SiO2-PNIPAM has also been proved by the investigation of the particle size and morphology with dynamic light scattering (DLS) and transmission electron microscope (TEM) below and beyond the phase transition temperature of PNIPAM. The microrheology of the PNIPAM microgel suspension has been investigated by using the prepared SiO2-PNIPAM particles as microrheological probes, and the results show that the diffusive coefficient of the probes in the swollen state is one-fifth of that in the collapsed state, and the viscosity of the PNIPAM microgel suspension in the swollen state is four times higher than that in the collapsed state, indicating SiO2-PNIPAM is a good probe in the microrheological study of PNIPAM microgel suspensions.


2013 ◽  
Vol 1552 ◽  
pp. 51-57
Author(s):  
Marina M. Leite ◽  
Flavio M. Vichi

ABSTRACTThe cubic perovskite SrTiO3 is an important semiconductor oxide with a band gap of 3.2 eV. It has a wide variety of applications such as: dielectric materials, photoluminescent devices, and in photocatalysis. It is conventionally obtained by the classic solid state synthesis (SS), in which TiO2 and SrCO3 react for several hours at temperatures as high as 1200 °C. Besides the high energy demand, SS is not useful for the control of physical characteristics, such as particle size and morphology, which has become essential for some of its applications. It is known that many soft and green routes can produce SrTiO3. Among them, the hydrothermal (HT) and sol-precipitation (SP) methods, as well as the molten salt synthesis (MS) are interesting not only due to their low cost and energy use, but also because of the possibility of particle size and shape control. This study compares the size and morphology of the SrTiO3 particles obtained by these three synthetic pathways. Scanning electron microscopy (SEM) was used to compare particle size and morphology, and X-ray diffraction (XRD) was used to confirm the perovskite formation as well as to determine the Scherrer’s particle size.


2011 ◽  
Vol 04 (03) ◽  
pp. 277-282 ◽  
Author(s):  
XIAOPING TANG ◽  
YANFENG GAO ◽  
HONGFEI CHEN ◽  
HONGJIE LUO

Lutetium disilicate (Lu2Si2O7) powders were prepared by a molten salt synthesis method. The effects of calcination temperature, reaction time, and surfactants on the properties of powders were investigated. The results revealed that with molten salts Lu2Si2O7 can be formed at 800°C. The particle size and morphology can be controlled by adding surfactants and changing reaction times. The formation mechanism and stability of Lu2Si2O7 structures were also discussed. The developed method for the synthesis of Lu2Si2O7 may pave the way for its application as environmental barrier coating materials.


RSC Advances ◽  
2015 ◽  
Vol 5 (18) ◽  
pp. 13331-13340 ◽  
Author(s):  
T. N. Ng ◽  
X. Q. Chen ◽  
K. L. Yeung

Flow-synthesis of mesoporous silica allows deliberate and precise control over the size and shapes and enables the preparation of complex microstructures (i.e., hollow spheres).


2021 ◽  
Vol 11 (14) ◽  
pp. 6578
Author(s):  
Aleksandra Jedlińska ◽  
Alicja Barańska ◽  
Dorota Witrowa-Rajchert ◽  
Ewa Ostrowska-Ligęza ◽  
Katarzyna Samborska

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.


2007 ◽  
Vol 336-338 ◽  
pp. 140-142
Author(s):  
Jun Jie Hao ◽  
Xiao Hui Wang ◽  
Shi Yun Lin ◽  
Long Tu Li

Na0.5Bi0.5TiO3 (NBT) is considered to be an excellent candidate for lead-free piezoelectric ceramics. In this study, we propose a hydrothermal method for the preparation of single phase NBT powder at relatively low treatment-temperature. The particle size and morphology of the synthesized powders were examined by SEM. The powders were further pressed into disk and sintered at 1120°C/2h in air, and its properties and microstructure were compared with traditionally prepared samples.


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