Synthesis of Uniform Barium Ferrite Powders by Co-Precipitation Method

2017 ◽  
Vol 898 ◽  
pp. 1649-1654 ◽  
Author(s):  
Min Chen ◽  
Run Hua Fan ◽  
Zi Dong Zhang ◽  
Yan Sheng Yin ◽  
Li Hua Dong
Keyword(s):  
Calcination Temperature ◽  
Barium Ferrite ◽  
Water Bath ◽  
Precipitation Method ◽  
Ammonium Bromide ◽  
Barium Ferrites ◽  
Hexagonal Barium Ferrite ◽  
Crystallite Sizes ◽  
Co Precipitation ◽  
Hexadecyltrimethyl Ammonium Bromide

The uniform hexagonal barium ferrite powders were synthesized by co-precipitation method using metal chloride. The effects of the amount of hexadecyltrimethyl ammonium bromide (CTAB), the water bath and calcination temperature on the phase formation, microstructure and density of barium ferrites were systematically investigated. The results showed that the formation of uniform hexagonal barium ferrite powders was significantly influenced by the amount of CTAB and the water bath could lead to the larger grain size and density. The SEM demonstrated that the BaFe12O19 powders had plate-like shape with crystallite sizes varing from 150 to 200 nm. When the amount of CTAB was 0.2g/100ml and the calcination temperature was 850 °C, the barium ferrite powders were uniform which indicated that the amount of surfactant and calcination temperature were very optimum.

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

scholarly journals Crystal Structure, Lattice Strain, Morphology, and Electrical Properties of SnO2 Nanoparticles Induced by Low Calcination Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Panya Khaenamkaew ◽  
Dhonluck Manop ◽  
Chaileok Tanghengjaroen ◽  
Worasit Palakawong Na Ayuthaya
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Calcination Temperature ◽  
Tin Dioxide ◽  
Lattice Strain ◽  
Dielectric Constants ◽  
Precipitation Method ◽  
Calcination Temperatures ◽  
Sensing Applications ◽  
Crystallite Sizes

The electrical properties of tin dioxide (SnO2) nanoparticles induced by low calcination temperature were systematically investigated for gas sensing applications. The precipitation method was used to prepare SnO2 powders, while the sol-gel method was adopted to prepare SnO2 thin films at different calcination temperatures. The characterization was done by X-ray diffraction, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The samples were perfectly matched with the rutile tetragonal structure. The average crystallite sizes of SnO2 powders were 45 ± 2, 50 ± 2, 62 ± 2, and 65 ± 2 nm at calcination temperatures of 300, 350, 400, and 450°C, respectively. SEM images and AFM topographies showed an increase in particle size and roughness with the rise in calcination temperature. The dielectric constant decreased with the increase in the frequency of the applied signals but increased on increasing calcination temperature. By using the UV-Vis spectrum, the direct energy bandgaps of SnO2 thin films were found as 4.85, 4.80, 4.75, and 4.10 eV for 300, 350, 400, and 450°C, respectively. Low calcination temperature as 300°C allows smaller crystallite sizes and lower dielectric constants but increases the surface roughness of SnO2, while lattice strain remains independent. Thus, low calcination temperatures of SnO2 are promising for electronic devices like gas sensors.

Synthesis of Fe3O4 Nanoparticles Prepared by Various Surfactants and Studying their Characterizations

2008 ◽  
Vol 273-276 ◽  
pp. 22-27 ◽  
Author(s):  
Ali Shokuhfar ◽  
S. Alibeigi ◽  
Mohammad Reza Vaezi ◽  
Sayed Khatiboleslam Sadrnezhaad
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Cetyl Trimethyl Ammonium Bromide ◽  
Precipitation Method ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Mixed Salt ◽  
Magnetite Fe3o4 ◽  
Cetyl Trimethyl Ammonium ◽  
Size And Morphology ◽  
Co Precipitation

Magnetite (Fe3O4) nanoparticles were prepared simply by the reverse co-precipitation method from the solution of ferrous/ferric mixed salt in the presence of cationic surfactant (cetyl trimethyl ammonium bromide, CTAB) and nonionic surfactant (Polyethylene glycol, PEG) in two concentrations. Meanwhile, Fe3O4 nanoparticles without surfactant are also synthesized under the same condition for comparison. In addition via the reverse co-precipitation method, the pH which is an important factor in synthesis of magnetite was controlled at high values easily. The experimental results reveal that addition of surfactants affected on the size and morphology of the nanoparticles based on the X-ray diffraction (XRD) and scanning electron microscope (SEM) characterizations.

The Influence of Calcination Temperature on Quantitative Phase of Hematite from Iron Stone Tanah Laut

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Co Precipitation

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.

Catalytic Hydrolysis of Hydrogen Cyanide on Cu-Al Catalyst

2015 ◽  
Vol 1094 ◽  
pp. 15-19
Author(s):  
Lin Xia Yan ◽  
Sen Lin Tian ◽  
Qiu Lin Zhang
Keyword(s):  
Calcination Temperature ◽  
Hydrogen Cyanide ◽  
Influence Factor ◽  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Cu Content ◽  
Co Precipitation ◽  
The Impact ◽  
Hydrolysis Of

Cu-Al catalysts were synthesized by the co-precipitation method to study hydrolysis of hydrogen cyanide. During the synthesis, the impact of Cu/Al molar ratio, pH value and calcination temperature was investigated and the best synthesis condition was found. The results indicate that the remove of hydrogen cyanide first increases and then decreases with increasing Cu/Al molar ratio, pH value and calcination temperature, which reaches the maxima and remains above 95% at 360 min when Cu/Al molar ratio is 2:1, pH value is approximately 8.0 and calcination temperature is 400°C around. The analysis of X-ray diffraction (XRD) shows that Cu content is the main influence factor at Cu/Al molar ratio below 2:1 whereas crystallinity of catalysts is the key factor at Cu/Al molar ratio above 2:1.

scholarly journals Influence of ZrO2 Nanoparticles on the Microstructural Development of Cement Mortars with Limestone Aggregates

2019 ◽  
Vol 9 (3) ◽  
pp. 598
Author(s):  
Danna Trejo-Arroyo ◽  
Karen Acosta ◽  
Julio Cruz ◽  
Ana Valenzuela-Muñiz ◽  
Ricardo Vega-Azamar ◽  
...  
Keyword(s):  
Xrd Analysis ◽  
Sem Analysis ◽  
Precipitation Method ◽  
Zro2 Nanoparticles ◽  
Microstructural Development ◽  
Cement Ratio ◽  
Cement Mortars ◽  
Crystallite Sizes ◽  
Co Precipitation ◽  
Two Stages

In this research, the effect of the addition of zirconium oxide-synthesized nanoparticles on the microstructural development and the physical–mechanical properties of cement mortars with limestone aggregates was studied. Zirconia nanoparticles were synthesized using the co-precipitation method. According to XRD analysis, a mixture of tetragonal (t) and monoclinic (m) zirconia phases was obtained, with average crystallite sizes around 15.18 and 17.79 nm, respectively. Based on the ASTM standards, a mixture design was obtained for a coating mortar with a final sand/cement ratio of 1:2.78 and a water/cement ratio of 0.58. Control mortars and mortars with ZrO2 additions were analyzed for two stages of curing of the mortar—7 and 28 days. According to SEM analysis, mortars with ZrO2 revealed a microstructure with a high compaction degree and an increase in compressive strength of 9% on the control mortars. Due to the aggregates’ characteristics, adherence with the cement paste in the interface zone was increased. It is suggested that the reinforcing effect of ZrO2 on the mortars was caused by the effect of nucleation sites in the main phase C–S–H and the inhibition of the growth of large CH crystals, and the filler effect generated by the nanometric size of the particles. This produced a greater compaction volume, suggesting that faults are probably originated in the aggregates.

scholarly journals Synthesis of Magnesium Aluminate Spinel Powder from the Purified Sodium Hydroxide Leaching Solution of Black Dross

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 741 ◽  
Author(s):  
Nguyen ◽  
Lee
Keyword(s):  
Sodium Hydroxide ◽  
Ball Milling ◽  
Calcination Temperature ◽  
Precipitation Method ◽  
Magnesium Aluminate ◽  
Magnesium Aluminate Spinel ◽  
Complete Conversion ◽  
Milling Method ◽  
Leaching Solution ◽  
Co Precipitation

Synthesis of magnesium aluminate spinel (MgAl2O4) was investigated by employing ball milling and co-precipitation methods. The starting materials (aluminum hydroxides) were obtained from the purified sodium hydroxide leaching solution of black dross. The characteristics of the synthesized spinel was analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM) images. In this work, the effect of calcination temperature and time on the formation of spinel by the two methods was compared. Calcination temperature showed a great effect on the formation of spinel in both methods. The results showed that the co-precipitation method has many advantages over the ball milling method. In ball milling method, complete conversion of the starting materials to spinel was impossible even at 1500 °C, while complete conversion to spinel was accomplished at 1000 °C for 5 h by the co-precipitation method. The average size of the spinel synthesized at these optimum conditions of the co-precipitation method was about 17 nm. A process can be developed to synthesize spinel from the black dross which is regarded as hazardous materials.

Co-Precipitation Synthesis of BiFeO3 Powders

2010 ◽  
Vol 105-106 ◽  
pp. 286-288 ◽  
Author(s):  
Hai Yang Bo ◽  
Guo Qiang Tan ◽  
Hong Yan Miao ◽  
Ao Xia
Keyword(s):  
Calcination Temperature ◽  
Bismuth Ferrite ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Infrared Spectrophotometer ◽  
Lower Temperature ◽  
Co Precipitation

Bismuth ferrite powders were synthesized by a simple citric acid complexing co-precipitation method at much lower temperature of 600°C. The work studies the calcination temperature and molar ratio of Fe and Bi on the structure and morphology. The as-prepared BiFeO3 powder was characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope and Fourier transform infrared spectrophotometer. The result shows that the phase pure BiFeO3 powders with cubic morphology were prepared as the calcination temperature was 600°C and molar ratio of Fe and Bi was 1:1. The nanoparticles was uniform with the size of about 200nm.

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