Synthesis of (Ba,Ti)-Doped Apatite-Type Lanthanum Silicate Nano-Sized Powders via Microwave-Assisted Sol-Gel Auto-Combustion Route

2013 ◽  
Vol 652-654 ◽  
pp. 882-885 ◽  
Author(s):  
Ran Wu ◽  
Jia Mei Ye ◽  
Qi Zhao Li ◽  
Sheng Yun Wang ◽  
Xiu Lei Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Sol Gel ◽  
Lanthanum Nitrate ◽  
Microwave Assisted ◽  
Auto Combustion ◽  
Combustion Route ◽  
Lanthanum Silicate ◽  
Apatite Type

In this paper, (Ba,Ti)-doped lanthanum silicate nano-sized powders have been synthesized via microwave assisted sol-gel auto-combustion route by using TEOS and lanthanum nitrate as the starting materials, citric acid and glycol as chelators. Both the phase compositions and morphologies of the obtained powders have been characterized. The results indicated that: the synthesized nano powders were characterized as fluffy aggregates with the particle size ranging from 50 to 100nm. As the doping contents of Ba increased, the crystalline sizes decreased and the aggregation were deteriorated, while the particle size decreased from 120nm to 80nm and the aggregation between particles were halted as the doping contents of Ti increased.

Low Temperature Synthesis of Lanthanum Silicate Apatite Type by Modified Sol Gel Process

2014 ◽  
Vol 975 ◽  
pp. 143-148 ◽  
Author(s):  
Agatha Matos Misso ◽  
Daniel Ricco Elias ◽  
Fernando dos Santos ◽  
Chieko Yamagata
Keyword(s):  
Colloidal Silica ◽  
High Efficiency ◽  
Ceramic Body ◽  
Low Cost ◽  
Sol Gel ◽  
Lanthanum Nitrate ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Lanthanum Silicate ◽  
Apatite Type

Rare earth silicate apatite type is a very important and promising material for application as an electrolyte in IT-SOFC (Intermediate Temperature Solid Oxide Fuel Cell). Lanthanum silicate apatite, La9,33Si6O26, exhibits high conductivity and has high efficiency, long term stability, fuel flexibility, low emissions and relatively low cost compared to yttria stabilized zirconia (YSZ - yttria stabilized zirconia), at temperatures between 600 to 800 °C. One of the problems of YSZ is its high operating temperature which results in long starting times and problems of mechanical and chemical compatibility. The interest of investigating lanthanum silicate apatite as an electrolyte is to overcome the problems caused by high temperature operation required by YSZ electrolyte. In the present study, sol-gel method was used to synthesize La9,33Si6O26. Initially, the reagents (sodium silicate and lanthanum nitrate) were mixed to obtain colloidal silica. Then, this gel containing lanthanum nitrate was thermally treated to allow the melting of lanthanum nitrate salt distributed on colloidal silica. The aim of this study was to verify if this method permits the formation of La9,33Si6O26 pure apatite phase, in order to obtain fine powders and uniform particles for further processing and obtaining a ceramic body.

Preparation and Properties of CoFe2O4 Synthesized by the Modified Citrate-Gel Method

2010 ◽  
Vol 644 ◽  
pp. 39-42 ◽  
Author(s):  
E.M. Múzquiz-Ramos ◽  
Dora A. Cortés-Hernández ◽  
O.A. Herrera-Romero ◽  
José C. Escobedo-Bocardo
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Magnetic Properties ◽  
Citric Acid ◽  
Saturation Magnetization ◽  
Sol Gel ◽  
Molar Ratio ◽  
Spinel Type ◽  
Wide Range ◽  
Auto Combustion

In this work, the synthesis of CoFe2O4 via sol-gel auto-combustion method, using iron nitrate, cobalt nitrate and citric acid, with subsequent heat treatment in air was studied. The effects of the molar ratio of the metal nitrates to citric acid and the heat treatment temperatures on the magnetic properties have been investigated. The X-ray diffraction patterns showed peaks consistent with cubic spinel-type structure. The average crystallite sizes were determined from the (311) peak of the diffraction pattern using Scherrer equation. Particle sizes in the range of 18-44 nm were obtained. The crystallite size increases with annealing temperature. Magnetic properties, such as saturation magnetization (Ms), remanent magnetization (Mr) and coercivity field (Hc) were measured at room temperature using a vibrating sample magnetometer. Saturation magnetization was found to increase with particle size, whereas coercivity was found to reduce exponentially as the particle size was increased, apart from the Hc of the sample treated at 300 °C. The present work shows that magnetic properties vary over a wide range by changing the synthesis conditions.

scholarly journals SURFACTANT-ASSISTED SOL-GEL AUTO-COMBUSTION SYNTHESIS OF SR-HEXAFERRITE NANOPOWDER USING DIFFERENT FUELS AND BASIC AGENTS

2012 ◽  
Vol 05 ◽  
pp. 744-751
Author(s):  
M. GHOBEITI HASSAB ◽  
S. A. SEYYED EBRAHIMI ◽  
R. DEHGHAN
Keyword(s):  
Citric Acid ◽  
Crystallite Size ◽  
Combustion Synthesis ◽  
Calcination Temperature ◽  
Cationic Surfactant ◽  
Sol Gel ◽  
Decyltrimethylammonium Bromide ◽  
Auto Combustion ◽  
Combustion Route ◽  
Surfactant Assisted

In this research Sr -hexaferrite powder was synthesized by a sol–gel auto-combustion route using two different fuels (glycine and citric acid) and two different basic agents (ammonia and trimethylamine). N -decyltrimethylammonium bromide ( C 13 H 30 BrN ) was also employed as a cationic surfactant. The results showed the finest crystallite size and the lowest calcination temperature have been obtained as 27.2 nm and 800 °C respectively, in the presence of citric acid, trimethylamine and surfactant.

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar
Keyword(s):  
Particle Size ◽  
Structural Parameters ◽  
Sol Gel ◽  
Average Particle Size ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Powder Xrd ◽  
Average Particle ◽  
Cobalt Ferrites ◽  
Auto Combustion

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

Effect of Annealing Temperature on Phase Transition of Nanoalumina Synthesized by Auto-Combustion Route

2016 ◽  
Vol 41 ◽  
pp. 74-86 ◽  
Author(s):  
Muhammad Adil ◽  
Hasnah Mohd Zaid ◽  
Kean Chuan Lee ◽  
Noor Rasyada Ahmad Latiff
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Amorphous State ◽  
Specific Area ◽  
Combustion Method ◽  
Gravimetric Analysis ◽  
Crystalline Phases ◽  
Auto Combustion

Nanocrystalline Al2O3 powder has been successfully synthesized by a simple and fast sol-gel auto-combustion method. The transformation of crystalline phases of as-synthesized nano powders was investigated through X-ray diffraction in terms of their crystallinity and crystallite size. Subsequently, a detailed transmission electron microscopy (TEM) investigation, including specific area electron diffraction (SAED) analysis revealed the crystallographic alterations and morphological information even at lattice scale which co-include the XRD analysis. The results obtained allow to explain the evolution of an amorphous state into different crystalline phases with increased calcining temperature; and their relation to particle size. The particle size is found to be closely related to phase transition of Al2O3 from γ → δ → θ → κ →α. The existence of distinctive bonds and band energy were studied by employing Fourier-transform infrared spectroscopy (FTIR) and UV-visible spectroscopy, respectively. On the other hand, thermo gravimetric analysis (TGA) had also been performed to confirm the phase purity of nano powder.

One-step synthesis of barium hexaferrite nano-powders via microwave-assisted sol–gel auto-combustion

2010 ◽  
Vol 30 (4) ◽  
pp. 993-997 ◽  
Author(s):  
Liu Junliang ◽  
Zeng Yanwei ◽  
Guo Cuijing ◽  
Zhang Wei ◽  
Yang Xiaowei
Keyword(s):  
Sol Gel ◽  
Barium Hexaferrite ◽  
Microwave Assisted ◽  
Auto Combustion ◽  
One Step

Study on the Synthesis of Batches of the System Y-Ba-Cu-O Using Sol-Gel Method

2014 ◽  
Vol 91 ◽  
pp. 19-23
Author(s):  
Plamen Pashev ◽  
Rositsa Raykova ◽  
Yancho Hristov ◽  
Bogdan Bogdanov
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Blue Solution ◽  
Transformation Processes ◽  
Nitrate Solutions ◽  
Thermally Treated

The study presented deal with preparation of batches of the system Y-Ba-Cu-O using sol-gel method and citric acid as precursor. Batches with particle size of 100 nm containing each of the phases Y123 and Y211 were prepared. The stoichiometric amounts of Y, Ba and Cu oxides were dissolved in 65% HNO3 until clear blue solution was observed under heating to 80 ̊С. The nitrate solutions obtained were neutralized to pH = 6 with 25% solution of NH3 (p.a.), then С6Н8О7 was added as the gels obtained were thermally treated. The transformation processes taking place under change of temperature were studied by IR, XRD, DTA and SEM.

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