Magnetic measurements and transmission electron microscopy investigatIons on Fe–Co ultrafine powders derived from a bimetallic carbonyl cluster

1994 ◽  
Vol 4 (2) ◽  
pp. 361-364 ◽  
Author(s):  
Giovanni Predieri ◽  
Luigi Pareti ◽  
Massimo Solzi ◽  
Aldo Armigliato ◽  
Simona Bigi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Measurements ◽  
Carbonyl Cluster ◽  
Ultrafine Powders ◽  
Transmission Electron

Study of Structural, Optical, Dielectric and Magnetic Properties of Zinc Ferrite Synthesized by Co-Precipitation

2017 ◽  
Vol 17 ◽  
pp. 1-9
Author(s):  
P. Annie Vinosha ◽  
L. Ansel Mely ◽  
J. Emima Jeronsia ◽  
F. Heartlin Monica ◽  
K. Raja ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Zinc Ferrite ◽  
Magnetic Measurements ◽  
Functional Dependence ◽  
Spectral Studies ◽  
Dielectric Studies ◽  
Transmission Electron ◽  
Co Precipitation

Spinel zinc ferrite (ZnFe2O4) nanoparticles have engrossed immense attention due to its unusual amalgamation of its properties especially the magnetic properties and these properties are catered as fitting candidates in the field of electronics. Nanostructured spinel zinc ferrite particles were synthesized using scalable co-precipitation technique. The morphology, particle size and reaction pace of the nanoparticles (NPs) were fine tuned by eco-friendly technique. These NPs were characterized by UV-Visible spectroscopy (UV-Vis), photoluminescence (PL), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Transmission electron microscopy (TEM), vibrating sample magnetometer ((VSM) and Dielectric studies. The required profiles were confirmed by XRD and FTIR spectra, UV-Vis, PL spectral studies. Further these measurements divulge the significance of optical properties and the spectral parameters are used to appraise the optical constants required for fabrication. Transmission electron microscopy eventually discloses the morphological analysis of the synthesized ZnFe2O4 nanoparticle as 15 nm within the scaling limitations. Using, VSM, the magnetic behaviour of the material have been determined as a function of magnetic field at ambient temperature; the magnetic measurements well-establishes the magnetic property and disclosed to have weak ferromagnetic behaviour as the crystallite size decreases. The A.C. conductivity measurements and dielectric studies were done as a functional dependence of frequency and temperature on synthesized nanoparticles.

Effect of Secondary Decomposition on Coercivity of Fe-Co-Cr Alloys with 15% Co

2015 ◽  
Vol 233-234 ◽  
pp. 623-628 ◽  
Author(s):  
Vladimir P. Menushenkov ◽  
Vladimir S. Shubakov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Volume Fraction ◽  
Magnetic Measurements ◽  
Magnetic Treatment ◽  
Magnetic Insulation ◽  
Transmission Electron ◽  
Microstructure And Magnetic Properties

The microstructure and magnetic properties of Fe-Co-Cr alloys with 15 wt % Co were investigated using transmission electron microscopy and magnetic measurements. The secondary decomposition within both the α2-phase matrix and the α1-phase particles was observed for magnets subjected thermo-magnetic treatment and subsequent stepped aging or continuous-cooling treatments. During high-temperature treatments (630-600оC), when the α2phase is dominant (the volume fraction is more than 50%), the secondary decomposition of this phase takes place (α2→ α1'+ α2'). The deterioration of magnetic insulation of α1-phase particles results in the decrease in the coercive force of alloys. Below 600оC, when the α1phase is dominant (the volume fraction is more than 50%), the splitting of elongated α1-phase particles occurs. When the temperature of stepped-aging decreases in high steps, the secondary decomposition (α1→ α1'+ α2') leads to the splitting of initial α1-phase particles into fine slightly elongated particles and the decrease in the coercive force.

Facile Fabrication of Single Crystalline Fe3O4 Nanorods and its Magnetic Properties

2011 ◽  
Vol 194-196 ◽  
pp. 638-642
Author(s):  
Gui Lian Li ◽  
Xian Ming Liu ◽  
Wei Dong Yin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Measurements ◽  
High Yield ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Single Crystalline ◽  
Transmission Electron ◽  
Facile Hydrothermal Route ◽  
Facile Fabrication

Single crystalline Fe3O4nanorods were fabricated in high yield via a facile hydrothermal route in the presence of sodium citrate as addition agent. The phase structures, morphologies, and sizes of as-prepared products were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The diameter of magnetite nanorods is about 50~80 nm and its length is more than 2 μm. Room-temperature magnetic measurements showed that Fe3O4nanorods exhibited high saturation magnetization and coercitivity of 77.8 emu/g and 98 Oe, respectively, while the as-obtained nanoparticles had low coercitivity value.

scholarly journals Synthesis, Characterization and Magnetic Hyperthermia of Monodispersed Cobalt Ferrite Nanoparticles for Cancer Therapeutics

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4428
Author(s):  
Mauricio A. Medina ◽  
Goldie Oza ◽  
A. Ángeles-Pascual ◽  
Marlene González M. ◽  
R. Antaño-López ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cobalt Ferrite ◽  
Magnetic Measurements ◽  
Cancer Therapeutics ◽  
Physiological Saline ◽  
Dark Field ◽  
Ferrite Nanoparticles ◽  
Cobalt Ferrite Nanoparticles ◽  
Transmission Electron

Magnetic nanoparticles such as cobalt ferrite are investigated under clinical hyperthermia conditions for the treatment of cancer. Cobalt ferrite nanoparticles (CFNPs) synthesized by the thermal decomposition method, using nonionic surfactant Triton-X100, possess hydrophilic polyethylene oxide chains acting as reducing agents for the cobalt and iron precursors. The monodispersed nanoparticles were of 10 nm size, as confirmed by high-resolution transmission electron microscopy (HR-TEM). The X-ray diffraction patterns of CFNPs prove the existence of cubic spinel cobalt ferrites. Cs-corrected scanning transmission electron microscopy–high-angle annular dark-field imaging (STEM–HAADF) of CFNPs confirmed their multi-twinned crystallinity due to the presence of atomic columns and defects in the nanostructure. Magnetic measurements proved that the CFNPs possess reduced remnant magnetization (MR/MS) (0.86), which justifies cubic anisotropy in the system. Microwave-based hyperthermia studies performed at 2.45 GHz under clinical conditions in physiological saline increased the temperature of the CFNP samples due to the transformation of radiation energy to heat. The specific absorption rate of CFNPs in physiological saline was 68.28 W/g. Furthermore, when triple-negative breast cancer cells (TNBC) in the presence of increasing CFNP concentration (5 mg/mL to 40 mg/mL) were exposed to microwaves, the cell cytotoxicity was enhanced compared to CFNPs alone.

TEM Study and Magnetic Measurements of Nano–Scale Particles Formed in Cu–Base Alloys

2010 ◽  
Vol 89-91 ◽  
pp. 757-762 ◽  
Author(s):  
Sung Kang ◽  
Teppei Muramatsu ◽  
Mahoto Takeda
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Phase Transformation ◽  
Magnetic Measurements ◽  
Precipitation Behavior ◽  
Nano Scale ◽  
Transmission Electron ◽  
Means Of Transmission

The precipitation behavior of nano–scale particles formed in Cu–base alloys was studied by means of transmission electron microscopy (TEM) and SQUID measurements. Linear arrangements of two or more nano–scale particles cubic in shape were observed in the <100> orientations of matrices in a Cu–Co alloy. Although the trend was less explicit in a Cu–Fe alloy, Fe precipitates accompanying twin–like lattice modulations were found in the decomposition, when no deformation was applied. The present SQUID measurements revealed several significant influences to magnetic properties were induced during the precipitation in Cu–base alloys. Lorentz electron microscopy confirmed that phase transformation from γ → α occurred at the stage that the Fe particles reach to 40~60nm in size.

Ferromagnetic Behaviour in Nanoscale Cobalt Particles Dispersed by Zeolite Na-X.

1995 ◽  
Vol 384 ◽  
Author(s):  
I. Hussain ◽  
I. Gameson ◽  
P.A. Anderson ◽  
P. P. Edwards
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Magnetic Measurements ◽  
Hydrogen Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Simple Solid State Reaction

ABSTRACTThis investigation has looked at the preparation of nanoscale cobalt particles by a simple solid state reaction involving cobalt (II) nitrate and zeolite Na-X under vacuum conditions followed by reduction in an hydrogen atmosphere. Samples were characterised by powder x-ray diffraction and scanning/transmission electron microscopy (TEM). Magnetic measurements were performed on the samples below 300 K using a SQUID magnetometer.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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