Effect of different fuels on the strontium hexaferrite nanopowder synthesized by a surfactant-assisted sol–gel auto-combustion method

2007 ◽  
Vol 353 (8-10) ◽  
pp. 814-816 ◽  
Author(s):  
M. Ghobeiti Hasab ◽  
S.A. Seyyed Ebrahimi ◽  
A. Badiei
Keyword(s):  
Sol Gel ◽  
Combustion Method ◽  
Strontium Hexaferrite ◽  
Auto Combustion ◽  
Surfactant Assisted

scholarly journals Y3+ substituted Sr-hexaferrites: sol-gel synthesis, structural, magnetic and electrical characterization

Cerâmica ◽  
2019 ◽  
Vol 65 (374) ◽  
pp. 274-281 ◽  
Author(s):  
S. S. Satpute ◽  
S. R. Wadgane ◽  
S. R. Kadam ◽  
D. R. Mane ◽  
R. H. Kadam
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Combustion Method ◽  
Hexagonal Structure ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
Auto Combustion

Abstract Y3+ substituted strontium hexaferrites having chemical composition SrYxFe12-xO19 (x= 0.0, 0.5, 1.0, 1.5) were successfully synthesized by sol-gel auto-combustion method. The structural and morphological studies of prepared samples were investigated by using X-ray diffraction technique, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy. The X-ray diffraction pattern confirmed the single-phase hexagonal structure of yttrium substituted strontium ferrite and the lattice parameters a and c increased with the substitution of Y3+ ions. The crystallite size also varied with x content from 60 to 80 nm. The morphology was studied by FE-SEM, and the grain size of nanoparticles ranged from 44 to 130 nm. The magnetic properties were investigated by using vibrating sample magnetometer. The value of saturation magnetization decreased from 49.60 to 35.40 emu/g. The dielectric constant decreased non-linearly whereas the electrical dc resistivity increased with the yttrium concentration in strontium hexaferrite.

scholarly journals THE EFFECT OF HIGH ENERGY MILLING ON THE SR-HEXAFERRITE NANOCRYSTALLINE POWDER SYNTHESIZED BY A SOL-GEL AUTOCOMBUSTION METHOD

2012 ◽  
Vol 05 ◽  
pp. 765-770
Author(s):  
S. SADEGHI-NIARAKI ◽  
S. A. SEYYED EBRAHIM ◽  
SH. RAYGAN
Keyword(s):  
Ball Mill ◽  
Sol Gel ◽  
Combustion Method ◽  
High Energy ◽  
Subsequent Annealing ◽  
Strontium Hexaferrite ◽  
Nanocrystalline Powder ◽  
X Ray ◽  
Auto Combustion ◽  
Xrd Patterns

In this research SrFe 12 O 19 nanocrystalline synthesized by sol-gel auto-combustion method and subsequent annealing at 1000°C for 1h subjected to mechanochemical treatment in a high-energy ball mill and then re-annealing. A planetary ball mill (Fritsch Pulveristte 6) was used to mill the strontium hexaferrite powder at 300 rpm in air for 10, 20 and 40 hours. The process was studied by X-ray diffraction technique and scanning electron microscopy. The X-ray study showed that SrFe 12 O 19 phase was decomposed by milling. Strontium hexaferrite and α- Fe 2 O 3 were obtained with 10 hours milling. There were α- Fe 2 O 3 and strontium hexaferrite in XRD patterns of 20 hours milled sample. With increasing of the milling time to 40 hours, strontium hexaferrite was decomposed completely. The annealing of the 20 and 40 h milled powders at 900°C for 1h led to the formation of single phase strontium hexaferrite with smaller crystallite size compare to that of the hexaferrite powder before milling and subsequent annealing.

Effect of annealing temperature on structural and magnetic properties of strontium hexaferrite nanoparticles synthesized by sol–gel auto-combustion method

2015 ◽  
Vol 29 (27) ◽  
pp. 1550190 ◽  
Author(s):  
Ebrahim Roohani ◽  
Hadi Arabi ◽  
Reza Sarhaddi ◽  
Saeedeh Sudkhah ◽  
Ameneh Shabani
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Magnetic Properties ◽  
Thermogravimetric Analysis ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Combustion Method ◽  
Strontium Hexaferrite ◽  
Auto Combustion ◽  
Ft Ir

In this paper, strontium hexaferrite nanoparticles were synthesized by the sol–gel auto-combustion method. Effect of annealing temperature on crystal structure, morphology and magnetic properties of nanoparticles was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Also, the thermal decomposition of as-synthesized powdered samples has been studied by thermogravimetric analysis (TGA). The XRD patterns confirmed the formation of single phase M-type hexagonal crystal structure for powders annealed above 950[Formula: see text]C, whereas the presence of hematite ([Formula: see text]-Fe2O3) as secondary phase was also observed for sample annealed at 900[Formula: see text]C. Furthermore, the crystallinity along with the crystallite size were augmented with annealing temperature. Comparison of the FT-IR spectra of the samples before and after annealing treatment showed the existence of metal–oxygen stretching modes after annealing. The thermogravimetric analysis confirmed the thermal decomposition of as-burnt powders happened in three-stage degradation process. The TEM images showed the nanoparticles like hexagonal-shaped platelets as the size of nanoparticles increases by increasing the annealing temperature. With increasing annealing temperature, the magnetic saturation and the coercivity were increased to the maximum value of 74.26 emu/g and 5.67 kOe for sample annealed at 1000[Formula: see text]C and then decreased.

Doping Effect on Crystal Structure and Magnetic Properties of Highly Al-Substituted Strontium Hexaferrite Nanoparticles

2012 ◽  
Vol 229-231 ◽  
pp. 210-214
Author(s):  
Elham Khorashadizade ◽  
Hadi Arabi ◽  
Abbas Yousefi
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Sol Gel ◽  
Combustion Method ◽  
Peak Position ◽  
Strontium Hexaferrite ◽  
Ionic Radii ◽  
Al Content ◽  
Auto Combustion ◽  
Substitution Ratio

M-type strontium hexaferrites with substitution of Fe3+by Al3+, according to the formula SrAlxFe12-xO19(x=0, 1, 2, 3, 4, 6, 8, 10), are prepared by the sol-gel auto-combustion method. Influences of the substituted amount of Al3+on structure and magnetic properties of SrAlxFe12-xO19compounds have systematically been investigated by XRD, TEM and VSM. X-ray diffraction shows that the samples are single M-type hexagonal ferrites. Because of the resemblance of Al3+ionic radii with Fe3+the two ions are easily replaced at any substitution ratio without changing the crystal structure. The materials show structural and morphology changes upon replacement of iron by aluminum. A shift in peak position to larger angles shown by XRD is observable with increasing aluminum doping. The values of Ms, Mr and Hc decrease with the addition of Al content but there is an exception for x=3 when Hc=8.9 KOe.

AN INVESTIGATION ON THE FORMATION OF STRONTIUM HEXAFERRITE NANO-POWDER BY A SOL-GEL AUTO-COMBUSTION METHOD IN THE PRESENCE OF SURFACTANT USING DIFFERENT BASIC AGENTS

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3159-3164 ◽  
Author(s):  
S. ALAMOLHODA ◽  
S. A. SEYYED EBRAHIMI ◽  
A. BADIEI
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Strontium Hexaferrite ◽  
Line Broadening ◽  
Hard Magnetic Material ◽  
Nano Powder ◽  
Auto Combustion ◽  
Scherrer Formula

Strontium hexaferrite is a hard magnetic material and has been extensively used as a permanent magnet. In this work a novel sol-gel auto-combustion method was used to synthesize ultra fine strontium hexaferrite. The investigations show that the model of combustion changes with the change of basic agent. The XRD results show that using ammonia or trimethylamine does not change the composition of the combustion product and it also shows that the surfactant burns completely during the combustion process. The average crystallite size of hexaferrite powders was also measured by X-ray line broadening technique employing Scherrer formula. The results show that changing the basic agent makes the particle size of the final product much smaller. Basic agent also affects the formation temperature of the single phase strontium hexaferrite.

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