Preparation and Microstructure of Co-Ferrite Fine Powder

2011 ◽  
Vol 328-330 ◽  
pp. 1365-1368
Author(s):  
Chang Sen Zhang ◽  
Lei Yang ◽  
Feng Zhou
Keyword(s):  
Grain Size ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Fine Powder ◽  
Precipitation Method ◽  
Mechanical Grinding ◽  
Gel Method ◽  
Sol Gel Method ◽  
Average Grain Size ◽  
Co Precipitation

Cobalt ferrites were prepared by citrate sol-gel method, chemical co-precipitation, mechanical grinding, respectively. The grain size, morphology, and the size of crystal particles were studied by x-ray diffraction (XRD) and scanning electron microscope (SEM). Cobalt ferrite showed different morphologys when prepared by different methods, It was tapered corners which prepared by sol-gel method; It was tetrahedral which prepared by mechanical grinding method; It was sphere which prepared by chemical co-precipitation method. The average grain size of cobalt ferrite was less than 100nm, while particles prepared by chemical precipitation method were the smallest. The size of Cobalt ferrite prepared by sol-gel method was decreased with the cobalt content increased.

Synthesis Processes of Nano Alumina Abrasive

2008 ◽  
Vol 368-372 ◽  
pp. 691-693 ◽  
Author(s):  
Zi Cheng Li ◽  
Zhi Hong Li ◽  
Ai Ju Zhang ◽  
Yu Mei Zhu
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Sol Gel ◽  
Precipitation Method ◽  
Pressureless Sintering ◽  
Gel Method ◽  
Sol Gel Method ◽  
Uniform Microstructure ◽  
Nano Alumina ◽  
Average Grain Size

Synthesis processes of nano alumina abrasive precursor using precipitation method and sol-gel method were investigated in this study. Using pressureless sintering, the nano alumina abrasive was prepared. Mechanical properties of the samples were measured by using single particle compressive strength tester. The microstructures of them were examined by using field emission scanning electron microscopy (FESEM). The results indicated that the performance and microstructure of the samples are greatly relative to the synthesis processes. Compared with samples prepared by precipitation method, the samples prepared by sol-gel method have higher compressive strength, smaller grain size and more uniform microstructure. The average grain size of the alumina abrasive was below 100nm.

scholarly journals The Influence of Annealing Temperature on the Structure and Magnetic Properties of Nanocrystalline BiFeO3 Prepared by Sol–Gel Method

2021 ◽  
Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Weak Ferromagnetism ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Average Grain Size ◽  
Spin Cycloid

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.

Study on Different Synthesis Methods of Spherical YAG:Ce3+ Phosphor and its Luminescence Properties

2015 ◽  
Vol 1088 ◽  
pp. 371-376 ◽  
Author(s):  
Xia Zhang ◽  
Cui Xia Yan ◽  
Rong Feng Guan
Keyword(s):  
Sol Gel ◽  
Spherical Particles ◽  
Luminescence Properties ◽  
Precipitation Method ◽  
Thermal Method ◽  
Synthesis Methods ◽  
Processing Parameter ◽  
Gel Method ◽  
Sol Gel Method ◽  
Co Precipitation

Spherical YAG:Ce3+phosphors were synthesized by three different routes namely sol-gel method, co-precipitation method and solvethermal method. The microstructure, crystallization and luminescent properties of the phosphors were studied in order to find the best processing parameter for spherical shape and good luminescence properties of YAG:Ce3+phosphor. Adding citric acid to the precursor solution resulted in the formation of spherical particles in sol-gel method. YAG:Ce3+phosphor made by co-precipitation method was separated with PEG2000, and its spherical particles of size was around 500nm. The hydro-thermal method could get perfect spherical appearance, but it needed heat treatment improve the luminescence property.

Synthesis and Characterization of Nanocrystalline PZT Powders by a Simple Sol-Gel Method

2012 ◽  
Vol 512-515 ◽  
pp. 147-152
Author(s):  
Shao Peng Zhang ◽  
Xiao Hui Wang ◽  
Long Tu Li
Keyword(s):  
Grain Size ◽  
Lead Zirconate Titanate ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Average Grain Size

Nanocrystalline lead zirconate titanate (PZT) powders with composition at the morphotropic phase boundary (MPB) were synthesized by a simple aqueous based sol-gel method, using lead nitrate, zirconium nitrate and tetrabutyl titanate as the starting materials. The sol could be easily transformed into gel, firstly heated at 120°C for 10h, then at 180°C for 24h. The thermal decomposition process of the gel was investigated by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The effect of citrate addition amount on the calcining temperature was discussed. The results reveal that pure perovskite phase PZT powders can be obtained at a calcining temperature as low as 600°C. The average grain size of the powders was determined by transmission electron microscope and X-ray diffraction. The influences of calcining temperature and the pH value of the solution on the grain size were investigated. The sintering temperature and electrical properties of the ceramics derived by nano-powders were compared with those prepared by the conventional ceramic processing. The result shows that using the nanopowder, the sintering temperature could be reduced by about 100°C and the ferroelectric properties were enhanced.

Comparative Study on the Microstructure and Photoluminescence Properties of SnO2 Nano Particles Prepared by Different Methods

2015 ◽  
Vol 719-720 ◽  
pp. 132-136 ◽  
Author(s):  
Ghazaleh Allaedini ◽  
Siti Masrinda Tasirin ◽  
Meor Zainal Meor Talib ◽  
Payam Aminayi ◽  
Ifa Puspasari
Keyword(s):  
Sol Gel ◽  
Spherical Shape ◽  
Nano Particles ◽  
Precipitation Method ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Significant Difference ◽  
Co Precipitation

This study presents comparisons between the morphologies and photoluminescence properties of tin oxide (SnO2) nanoparticles prepared by two methods, namely the sol gel and the co-precipitation methods. The characteristics of the particles were analyzed using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The particles prepared using the sol-gel method have a finer particle size and more spherical shape. However, no significant difference was observed in terms of morphology and homogeneity in the samples produced by either the co-precipitation or sol-gel methods. In contrast, the photoluminescence study shows that the emission peak for powder prepared using the sol-gel method was higher than that of the co-precipitation method.

Synthesis of Sr4Al14O25:Eu2+, Dy3+ via Using Cyclodextrin as Chelating Agent by Sol-Gel Method

2014 ◽  
Vol 809-810 ◽  
pp. 702-706
Author(s):  
Wen Feng Xu ◽  
Cheng Li Liao ◽  
Fu Hang Xiong ◽  
Kui Li ◽  
Xiao Ling Liao
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Sol Gel ◽  
Chelating Agent ◽  
Gel Method ◽  
Sol Gel Method ◽  
Reducing Atmosphere ◽  
Average Grain Size ◽  
Pure Phase ◽  
First Time

Sr4Al14O25:Eu2+, Dy3+ luminescent phosphor was synthesized for the first time from using cyclodextrin as chelating agent by sol-gel method. The structural characterization, surface morphology and properties of the phosphor were studied. The results revealed that the target phosphor with relatively regular morphology, smaller grain size, pure phase and high crystallinity can be achieved at 1200°C for 4 h in a reducing atmosphere. The average grain size of the Sr4Al14O25:Eu2+, Dy3+ phosphor nanoparticles ranges from 50 to 100 nm . And the phosphorescence in blue-green (483 nm) by Eu2+.

Effect of TiCl4 Concentration and Acidity on Size and Phase of TiO2 Nanopowders Prepared by Non-Hydrolytic Sol-Gel Method

2011 ◽  
Vol 412 ◽  
pp. 32-35
Author(s):  
Jian Sun ◽  
Yan Xiang Wang ◽  
Xiao Yan Li
Keyword(s):  
Grain Size ◽  
Sol Gel ◽  
Rutile Phase ◽  
Gel Method ◽  
Sol Gel Method ◽  
Reaction Solution ◽  
Average Grain Size ◽  
Method Effects

TiO2nanopowders were synthesized by non-hydrolytic sol−gel method. Effects of TiCl4concentration and acidity on the properties of TiO2nanopowders were investigated. The results showed that the average grain size of TiO2decreased with the increasing of TiCl4concentration. H+can inhibit the growth of TiO2particles and Cl-is conducive to the formation of rutile phase. When 2.06M HCl was used as the reaction solution, TiO2microspheres with diameter 2μm was obtained, and TiO2microspheres was composed of anatase and rutile phase.

Effect of Synthesis methods on the Properties of Magnetic Material

2015 ◽  
Vol 10 (1) ◽  
pp. 2566-2582
Author(s):  
Anwar Ul Haq ◽  
Farwa Mushtaq ◽  
M. Anis-ur-Rehman
Keyword(s):  
Sol Gel ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Basic Material ◽  
Synthesis Methods ◽  
Hydraulic Pressure ◽  
Phase Purity ◽  
Gel Method ◽  
Sol Gel Method ◽  
Co Precipitation

Ba1-xPbxFe12O19 composition (x=0.0 to 1.0) synthesized by Co-precipitation and Sol-Gel  methods. In Co-precipitation method BaCO3, PbO and Fe (NO3)3 .9H2O were used as basic ingredients. Acids and Di-H2O  were used as solvents. Molar ratio of cations was 12.   pH of solution kept constant at 13.  All samples sintered at 965±5oC for three hours.  Lead own properties, synthesis at room temperature and substitution in R-block of structure were the reasons for decrease of phase purity from “x” =0.0 to 70% for “x”=1.0. Decrease in phase purity   and heterogeneity of material caused the properties to decrease. In Sol gel method, Nitrates (salts) and Ethylene glycol (liquid) were the basic material used. The mixed solutions dried out on a hot plate whose temperature was maintained constant at 200±2oC. Pellets formed by applying suitable hydraulic pressure and then sintered at same temperature written above i.e. 965±5oC for three hours. 100% phase purity achieved. All properties modified. Temperature and frequency dependent electrical properties investigated and reported here. DC and AC obtained properties were useful for different electronics and computer devices like capacitors, smart storage devices and multilayer chip inductors. Overall, both these properties improved through sol-gel method as compared to co-precipitation method. It was because of improvement in phase purity and change in morphology of synthesized material. 

Panoscopic Assembling of Ceramic Materials for High Performance UV-Ray Shielding Application

2010 ◽  
Vol 63 ◽  
pp. 107-113
Author(s):  
Tsugio Sato ◽  
Xiang Wen Liu ◽  
Shu Yin
Keyword(s):  
High Performance ◽  
Sol Gel ◽  
Lithium Titanate ◽  
Nano Particles ◽  
Precipitation Method ◽  
Gel Method ◽  
Sol Gel Method ◽  
Uv Shielding ◽  
Micro Particles ◽  
Co Precipitation

The hybrid materials consisting of plate-like potassium lithium titanate (K0.81Li0.27Ti1.73O4) micro particles coated with calcia-doped ceria (Ce0.8Ca0.2O1.8) nano particles were prepared by the co-precipitation method and sol-gel method. Broad-spectrum UV-shielding composite materials with good comfort and low oxidation catalytic activity were successfully synthesized. The comfort when applied on skin and UV-shielding ability of the composites prepared by the sol-gel method were superior to those by the co-precipitation method.

Sign in / Sign up

Export Citation Format

Share Document