The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Abolghasem Ataie - One of the best experts on this subject based on the ideXlab platform.
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influence of fe ba molar ratio on the characteristics of ba hexaferrite particles prepared by sol gel combustion method
Journal of Alloys and Compounds, 2005Co-Authors: A Mali, Abolghasem AtaieAbstract:Abstract Nano-crystalline particles of barium hexaferrite (BaFe 12 O 19 ) have been prepared by a sol–gel combustion technique using nitrate–Citrate gels prepared from metal nitrates and citric acid solutions under various Fe/Ba molar ratios of 10, 11 and 12. The thermal decomposition process of the nitrate–Citrate gels and as-burnt powders was investigated by XRD and DTA/TGA techniques. The results revealed that the nitrate Citrate gels exhibit a self-propagating behavior after ignition and the single-phase barium hexaferrite formation temperature is significantly influenced by Fe/Ba molar ratio. The Fe/Ba molar ratio of 11 is more favorable for formation of barium hexaferrite. The SEM investigations revealed that the mean particle size of barium hexaferrite dramatically increases with increasing calcination temperature from 1000 to 1100 °C. The magnetic properties measured using a vibrating sample magnetometer (VSM) revealed that the sample synthesized under Fe/Ba molar ratio of 11, exhibits higher saturation magnetization in comparison with those synthesized under Fe/Ba molar ratios of 10 and 12.
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influence of the metal nitrates to citric acid molar ratio on the combustion process and phase constitution of barium hexaferrite particles prepared by sol gel combustion method
Ceramics International, 2004Co-Authors: A Mali, Abolghasem AtaieAbstract:A novel sol–gel combustion process was used to synthesize the ultrafine particles of barium hexaferrite. The nitrate–Citrate gels were prepared from metal nitrates and citric acid solutions under various molar ratios of the metal nitrates to citric acid of 0.5, 1, 1.5 and 3 by sol–gel process. The results showed that the nitrate Citrate gels exhibit a self-propagating behavior after ignition in air at room temperature. The thermal decomposition of nitrate–Citrate gels and the phase evolution of calcined powder were investigated respectively by DTA/TG and XRD techniques. Scanning electron microscope was used to characterize the microstructure of the products. The results revealed that the formation temperature and the crystallite size of barium hexaferrite are influenced significantly by the molar ratio of the metal nitrates to citric acid. The formation temperature of barium hexaferrite decreases with increasing the molar ratio of the metal nitrates to citric acid. © 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Zhilun Gui - One of the best experts on this subject based on the ideXlab platform.
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synthesis of nanocrystalline nicuzn ferrite powders by sol gel auto combustion method
Journal of Magnetism and Magnetic Materials, 2000Co-Authors: Zhenxing Yue, Ji Zhou, Hongguo Zhang, Zhilun GuiAbstract:Abstract A nitrate–Citrate gel was prepared from metal nitrates and citric acid by sol–gel process, in order to synthesize Ni 0.25 Cu 0.25 Zn 0.50 Fe 2 O 4 ferrite. The thermal decomposition process was investigated by DTA-TG, IR and XRD techniques. The results revealed that the nitrate–Citrate gel exhibits self-propagating combustion behavior. After combustion, the gel directly transformed into single-phase, nano-sized NiCuZn ferrite particles with spinel crystal structure. The synthesized powder can be densified at a temperature lower than 900°C. The sintered body possesses fine-grained microstructure, good frequency stability and high-quality factor compared to the sample prepared by conventional ceramic route.
Wensheng Yang - One of the best experts on this subject based on the ideXlab platform.
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synthesis of triangular silver nanoprisms by stepwise reduction of sodium borohydride and trisodium Citrate
Journal of Physical Chemistry C, 2010Co-Authors: Xinyi Dong, Mingyue Li, Jing Jing, Xiaohui Ji, Jun Li, Wensheng YangAbstract:Triangular silver nanoprisms were synthesized by stepwise reduction of silver nitrate with sodium borohydride (NaBH4) and trisodium Citrate. In this approach, first small spherical silver nanoparticles were prepared by the rapid reduction of the precursor with NaBH4 at ice-bath temperature. After being heated to 70 °C, further reduction of the precursor contributed to the formation of additional small spherical silver nanoparticles attributed to the catalysis effect of the silver particles formed at the low temperature. The residual precursor after the formation of the small spherical silver nanoparticles is necessary to promote the dissolution of the small nanoparticles and their transformation into the triangular nanoprisms. After consumption of most of the precursor, the nanoprisms became more uniform in shape and size driven by the Ostwald ripening. The triangular nanoprisms prepared by such an approach are expected to be potentially useful in biolabeling since the Citrate ligand on the nanoprism surf...
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shape control of silver nanoparticles by stepwise Citrate reduction
Journal of Physical Chemistry C, 2009Co-Authors: Xinyi Dong, Lili Zhao, Wensheng YangAbstract:Growth of silver nanoparticles by the Citrate reduction of silver nitrate under the range of pH from 5.7 to 11.1 was investigated systematically and quantitatively. Reduction of the silver precursor (Ag+) was promoted with increased pH, attributed to the higher activity of the Citrate reductant under high pH value. Under high pH, the product was composed of both spherical and rod-like silver nanoparticles as a result of the fast reduction rate of the precursor. Under low pH, the product was mainly dominated by triangle or polygon silver nanoparticles due to the slow reduction rate of the precursor. The product that is dominated by spherical silver nanoparticles cannot be acquired by the one-step Citrate reduction method in the range of pH investigated, indicating the poor balance between the nucleation and growth processes in the reactions. On the basis of the results of quantitative analyses, a stepwise reduction method, in which the nucleation and growth processes were carried out at high and low pH, re...
A Mali - One of the best experts on this subject based on the ideXlab platform.
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influence of fe ba molar ratio on the characteristics of ba hexaferrite particles prepared by sol gel combustion method
Journal of Alloys and Compounds, 2005Co-Authors: A Mali, Abolghasem AtaieAbstract:Abstract Nano-crystalline particles of barium hexaferrite (BaFe 12 O 19 ) have been prepared by a sol–gel combustion technique using nitrate–Citrate gels prepared from metal nitrates and citric acid solutions under various Fe/Ba molar ratios of 10, 11 and 12. The thermal decomposition process of the nitrate–Citrate gels and as-burnt powders was investigated by XRD and DTA/TGA techniques. The results revealed that the nitrate Citrate gels exhibit a self-propagating behavior after ignition and the single-phase barium hexaferrite formation temperature is significantly influenced by Fe/Ba molar ratio. The Fe/Ba molar ratio of 11 is more favorable for formation of barium hexaferrite. The SEM investigations revealed that the mean particle size of barium hexaferrite dramatically increases with increasing calcination temperature from 1000 to 1100 °C. The magnetic properties measured using a vibrating sample magnetometer (VSM) revealed that the sample synthesized under Fe/Ba molar ratio of 11, exhibits higher saturation magnetization in comparison with those synthesized under Fe/Ba molar ratios of 10 and 12.
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influence of the metal nitrates to citric acid molar ratio on the combustion process and phase constitution of barium hexaferrite particles prepared by sol gel combustion method
Ceramics International, 2004Co-Authors: A Mali, Abolghasem AtaieAbstract:A novel sol–gel combustion process was used to synthesize the ultrafine particles of barium hexaferrite. The nitrate–Citrate gels were prepared from metal nitrates and citric acid solutions under various molar ratios of the metal nitrates to citric acid of 0.5, 1, 1.5 and 3 by sol–gel process. The results showed that the nitrate Citrate gels exhibit a self-propagating behavior after ignition in air at room temperature. The thermal decomposition of nitrate–Citrate gels and the phase evolution of calcined powder were investigated respectively by DTA/TG and XRD techniques. Scanning electron microscope was used to characterize the microstructure of the products. The results revealed that the formation temperature and the crystallite size of barium hexaferrite are influenced significantly by the molar ratio of the metal nitrates to citric acid. The formation temperature of barium hexaferrite decreases with increasing the molar ratio of the metal nitrates to citric acid. © 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Alireza Badiei - One of the best experts on this subject based on the ideXlab platform.
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an investigation on physical properties of strontium hexaferrite nanopowder synthesized by a sol gel auto combustion process with addition of cationic surfactant
Journal of The European Ceramic Society, 2007Co-Authors: Ghobeiti M Hasab, S Seyyed A Ebrahimi, Alireza BadieiAbstract:Abstract In this study a novel sol–gel auto-combustion method, using n -decyltrimethylammonium bromide as a cationic surfactant, has been used to synthesize strontium hexaferrite nanocrystalline powder. The dried nitrate–Citrate gel, prepared from a solution of ferric nitrate, strontium nitrate, citric acid, trimethylamine and cationic surfactant, exhibited an auto-combustion behavior after ignition in air. The formation reaction temperature, phase identification, crystallites size, particles size distribution and morphology of resultant strontium hexaferrite powder were investigated by DTA/TGA, FTIR, XRD, LPSA, TEM and SEM techniques. The results showed that in presence of the cationic surfactant, the combustion intensity increases and the crystallite size decreases. The crystallite size of strontium hexaferrite powder in sample with surfactant calcined at 800 °C was 27.2 nm.