Increased coercivity in recalcined barium ferrite–magnetite nanocomposites

2021 ◽  
Vol 112 (5) ◽  
pp. 384-390
Author(s):  
Mohammad Jafar Molaei ◽  
Abolghasem Ataie ◽  
Shahram Raygan
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Magnetic Properties ◽  
Barium Ferrite ◽  
Average Particle Size ◽  
Particle Morphology ◽  
High Energy ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray

Abstract In this research, mixtures of barium ferrite and graphite were milled in a high-energy mechanical milling machine. The effect of recalcination on the magnetic properties of the milled samples was studied. Phase analysis, phase transformations at high temperatures, particle size distribution, magnetic properties, and particle morphology were characterized by means of X-ray diffraction, hot stage X-ray diffraction, dynamic light scattering, vibrating sample magnetometry, high-resolution transmission electron microscopy, and field-emission scanning electron microscopy, respectively. A magnetic nanocomposite of BaFe12O19/Fe3O4 formed after 20 and 40 h milling. The average particle size for the 20 and 40 h milled samples reached 106 and 68 nm, respectively. Recalcination of the milled samples resulted in barium ferrite structure recovery. The decreased particle size due to the milling and subsequent recalcination results in increased coercivity values. The coercivity for the milled and calcined sample could increase more than 40% compared to as-received barium ferrite and reaches 3935 Oe for the sample calcined at 1050 °C.

Hydrothermal Synthesis of Monodisperse α-Fe2O3 Nanoparticles

2011 ◽  
Vol 236-238 ◽  
pp. 1814-1817
Author(s):  
Hong Wang ◽  
Yan Jie ◽  
Hong Luo ◽  
Xue Feng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Fourier Transform ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Scanning Electron

Monodisperse α-Fe2O3nanoparticles with average particle size of 110 nm were successfully prepared using olyvinylpyrrolidone (PVP) as surfactant via a novel hydrothermal route. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). The experiments results revealed that PVP and the concentration of NH4HCO3have played a crucial role in the formation of the monodisperse a-Fe2O3nanoparticles.

The Synthesis of Nano-Structured TiO2 Ceramics by Modified Two Step Sintering

2012 ◽  
Vol 500 ◽  
pp. 29-33
Author(s):  
Bao Rang Li ◽  
Xin Ming Xi ◽  
Yang Bai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

The nano-TiO2powders with the average particle size of about 40nm were used as starting materials. The compacted powders were firstly performed in Spark-plasma-sintering (SPS) at a high temperature and then sintered in air for hours at a relatively low temperature. The obtained samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed an obvious reduction in grain size was achieved by taking advantage of modified two step sintering (MTSS). The value of the relative grain growth d/do for the samples prepared by MTSS was less than 3.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

DIELECTRIC PROPERTIES OF ULTRAFINE Zn-DOPED CaCu3Ti4O12 CERAMIC

2012 ◽  
Vol 02 (01) ◽  
pp. 1250007 ◽  
Author(s):  
LAXMAN SINGH ◽  
U. S. RAI ◽  
K. D. MANDAL ◽  
MADHU YASHPAL
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sintered Powder

Ultrafine powder of CaCu2.80Zn0.20Ti4O12 ceramic was prepared using a novel semi-wet method. DTA/TG analysis of dry powder gives pre-information about formation of final product around 800°C. The formation of single phase was confirmed by X-ray diffraction analysis. The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm, respectively. Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic. Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.

Structural, Optical and Magnetic Properties of Ni Doped ZnS Nanoparticles

2018 ◽  
Vol 24 (8) ◽  
pp. 5640-5644
Author(s):  
B Sreenivasulu ◽  
S. Venkatramana Reddy ◽  
P. Venkateswara Reddy
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Absorption Spectra ◽  
Spherical Surface ◽  
Room Temperature Ferromagnetism ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Chemical Compositions ◽  
Average Particle ◽  
X Ray

Pure ZnS and 3 mol% of Ni doped ZnS nano powders are prepared by chemical co-precipitation method. Properties of ZnS: Ni2+ nanoparticles are studied by X-ray diffraction Spectra (XRD), Raman spectroscopy (RS), Photoluminescence (PL), Absorption Spectra, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDAX), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM). From XRD data, it conform the structure of ZnS, and particle size of pure and Ni doped ZnS data indicates the incorporation of Ni2+ in ZnS nanocrystal lattice. Raman spectra for pure and Ni doped samples exhibited vibrational modes confirm the structure of ZnS. Photoluminescence spectra reveal that the emission peaks are in UV and visible regions; this is confirming the absorption spectra. SEM micrographs show spherical morphology, and chemical compositions of samples are in stoichiometric proportions. TEM micro graphs show the spherical surface morphology and average particle size for pure and Ni2+ doped nanoparticles are in the range of 2–3 nm, this is good agreement with XRD results. M–H curves from VSM show room temperature ferromagnetism.

scholarly journals Structural and Magnetic Properties of Ni/C Composites Synthesized from Beet Pulp and Corn Stems

2021 ◽  
Vol 7 (3) ◽  
pp. 31
Author(s):  
Ihor Bordun ◽  
Anna Pidluzhna ◽  
Fedir Ivashchyshyn ◽  
Anatoliy Borysiuk ◽  
Dariusz Całus ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Raw Materials ◽  
Average Particle Size ◽  
Carbon Composites ◽  
Activation Technique ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beet Pulp ◽  
Promising Application

Nickel/carbon composites were synthesized by the carbonization method with the use of the steam-gas activation technique. Beet pulp and corn stems were used as initial raw materials for composites synthesis. The obtained substances were analyzed by means of scanning electron microscopy, X-ray diffraction analysis, and magnetic properties investigation. The presence of nickel in synthesized composites was estimated during analysis, and the average particle size of nickel was determined as well. The specific surface area of the obtained samples was measured by the technique of Methylene blue sorption from the aqueous solution. The results of the performed investigation demonstrate clearly the promising application of synthesized composites as magneto-active sorbents, which could be easily separated from water solutions.

scholarly journals Synthesis and Characterization of Cu2FeSnSe4 Nanofilms

2021 ◽  
pp. 1873-1878
Author(s):  
Omar Abdulsada Ali ◽  
Sarmed S.M. Al-Awadi
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Photovoltaic Applications ◽  
Tem Transmission Electron Microscopy

Well dispersed Cu2FeSnSe4 (CFTSe) nanofilms were synthesized by hot-injection method. The structural and morphological measurements were characterized using XRD (X-ray diffraction), Raman spectroscopy, SEM (scanning electron microscopy), and TEM (transmission electron microscopy). Chemical composition and optical properties of as-synthesized CFTSe nanoparticles were characterized using EDS (energy dispersive spectroscopy) and UV-Vis spectrophotometry. The average particle size of the nanoparticles was about 7-10 nm. The UV-Vis absorption spectra showed that the synthesized CFTS nanofilms have a band gap (Eg) of about 1.16 eV. Photo-electrochemical characteristics of CFTSe nanoparticles were studied and indicated their potential application in photovoltaic applications.

Synthesis and Characterization of High Density and Low Temperature Sintered Proton Conductor BaCe0.5Zr0.35In0.1Zn0.05O3-δ

2015 ◽  
Vol 1098 ◽  
pp. 104-109 ◽  
Author(s):  
Abul Kalam Azad ◽  
D.D.Y. Setsoafia ◽  
L.C. Ming ◽  
Iskandar Petra
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Proton Conductor ◽  
Solid State Reaction Method ◽  
Proton Conductors ◽  
Orthorhombic Symmetry ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Proton Uptake

Rare-earth-doped BaCeO3and BaZrO3electrolytes with perovskite structure have been studied extensively in developing proton conducting intermediate temperature SOFC. Acceptor doped alkaline earth cerates and zirconates have been thoroughly studied because of the great interest in their possible applications as solid proton conductors. The perovskite type proton conductor BaCe0.5Zr0.35In0.1Zn0.05O3-δwas prepared in the traditional solid state reaction method. The density of the sample obtained about 96% of the theoretical density after sintering at 1350 °C and X-ray diffraction study confirms the pure phase. Rietveld refinement of the neutron and X-ray powder diffraction data shows that this material crystallizes in the orthorhombic symmetry in the space group Pm3m. Particle size measurement shows that the average particle size is about 2.4 μm. The average thermal expansion at 894 °C was 9.49 x 10-6/°C. Thermogravimetric analysis (TGA) traces obtained for the sample on heating in wet air shows that the maximum proton uptake occurs from 595 °C.

IMPACT OF SURFACTANTS ON PHYSICAL PROPERTIES OF BaTiO3 NANOPARTICLES

2013 ◽  
Vol 12 (01) ◽  
pp. 1350003 ◽  
Author(s):  
R. VIJAYALAKSHMI ◽  
V. RAJENDRAN
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Average Particle Size ◽  
Ammonium Bromide ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanocrystalline BaTiO3 particles of about 20–35 nm have been successfully synthesized by using cationic, anionic and nonionic surfactants such as cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and poly ethylene glycol (PEG) via hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy. The average particle size, measured by powder X-ray diffraction was determined to be 20–35 nm and was confirmed by transmission electron microscopy. Spherical-like morphologies were obtained by scanning electron microscopy (SEM) analysis. Optical properties of products were investigated by ultraviolet-visible (UV-Vis) absorption and PL spectroscopies.

Microstructural Characterization of 66%Co-28%Cr-6%Mo Dental Alloy Powder Obtained by High-Energy Ball Milling

2014 ◽  
Vol 802 ◽  
pp. 51-55 ◽  
Author(s):  
Claudinei dos Santos ◽  
Alexandre Fernandes Habibe ◽  
Durval Rodrigues ◽  
José C. Minatti ◽  
Jefferson Fabrício C. Lins ◽  
...  
Keyword(s):  
Ball Milling ◽  
Average Particle Size ◽  
Microstructural Characterization ◽  
High Energy ◽  
Inert Atmosphere ◽  
High Energy Ball Milling ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball

In this work, the microstructural features of the particles based on 66% Co-28% Cr-6% Mo alloy, were investigated by X-ray diffraction and Scanning electron microscopy (SEM). Powders obtained by high-energy ball milling in an inert atmosphere, and held in SPEX mill with times between 15min and 120min, about ball/powder ratio of 6:1, were characterized by X-ray diffraction indicating in all conditions, Co phase as the crystalline phase of the system. The powders have a morphology that indicate a continuous reduction in average particle size as a function of increasing time, however, the shape of the particles initially flat for times up to 30 minutes, becomes spherodized after 30 minutes of grinding.

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