scholarly journals Studying the influence of synthesis parameters on the magnetic properties of CoNe ferrites

2020 ◽  
Vol 3 (2) ◽  
pp. 33-38
Author(s):  
L. A. Frolova ◽  
◽  
T. Ye. Butyrina ◽  
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Magnetic Hysteresis ◽  
Reaction Medium ◽  
Nonequilibrium Plasma ◽  
Treatment Temperature ◽  
Synthesis Conditions ◽  
Synthesis Parameters ◽  
Initial Ph ◽  
Mathematical Equations

The influence of synthesis conditions on saturation magnetization and coercive force of NiCo ferrites, which were obtained under the action of low-temperature contact nonequilibrium plasma (PNP), is investigated. The main influencing factors were the initial pH of the solution, the treatment temperature and the duration of plasma treatment. Mathematical equations adequately describe the obtained dependences. The results showed that the pH of the reaction medium is the parameter that most affects the magnetic hysteresis for samples obtained by processing KNP. Increasing the initial pH leads to an increase in coercive force.

scholarly journals Changing the Magnetic Properties of Cobalt Ferrite Nanoparticles with Different Fabrication Conditions

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Nguyen Ngoc Huyen ◽  
Nguyen Thi Minh Hong ◽  
Pham Duc Thang ◽  
Tran Dang Thanh ◽  
Ho Thi Anh
Keyword(s):  
Magnetic Properties ◽  
Spinel Structure ◽  
Cobalt Ferrite ◽  
Magnetic Hysteresis ◽  
Average Diameter ◽  
Xrd Analysis ◽  
Degree Of Crystallinity ◽  
Nanocrystalline Powders ◽  
Hydrothermal Route ◽  
Synthesis Conditions

In this study, crystalline nanoparticles CoFe2O4 with a spinel structure were prepared by hydrothermal methods. The magnetic properties of non-calcined cobalt ferrite formed from nanocrystalline powders. The dependence of the particle size and crystalline structure of obtained nanoparticles in the synthesis conditions was examined and characterized using field emission scanning electron microscope (FESEM), and X-ray diffraction analysis (XRD). The XRD analysis revealed a high degree of crystallinity and confirmed the spinel structure of crystalline nanoparticles CoFe2O4. The FESEM image shows the presence of spherical ferrite particles with an average diameter of about 13-18 nm. The results also show that the formation of cobalt ferrite spinel structures was affected by fabrication conditions. Magnetic hysteresis loop data confirm that the magnetic properties of nanoparticles depend on the synthesis conditions. The material prepared by the hydrothermal route and calcination at 150ºC with molar ration Co2+: Fe3+ = 1:2.2  for 2 hours has higher magnetic saturation than that of the surveyed samples.

scholarly journals Features of heat treatment quality testing of U8A steel articles during pulsed bipolar asymmetric magnetization

2020 ◽  
Vol 64 (4) ◽  
pp. 398-405
Author(s):  
Z. M. Korotkevich ◽  
V. A. Burak
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Coercive Force ◽  
Magnetic Induction ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Treatment Temperature ◽  
Treatment Quality ◽  
Magnetic Parameters ◽  
Quality Testing

To detect deviations of required heat treatment temperature of tool carbon steel U8A is one of the important tasks of manufactured products quality assurance. By analyzing researchings, held earlier, it was found that most of instrumental carbon steels standard magnetic characteristics have ambiguous dependence from the heat treatment temperature and cannot be used for purposes of nondestructive testing. Results of researching magnetic parameters of high-quality tool carbon steel U8A, which are good for heat treatment quality testing, are considered. The parameters were defined on steel cylindrical samples by the instrument IMI–I, suited for measuring the ferromagnetic rods magnetic induction during pulsed magnetization in open magnetic circuit. Applicability of the difference δBmp–Br between the magnetic induction of maximum demagnetizing pulse amplitude and the residual magnetic induction for tool carbon steel U8A hardening temperature testing is determined. The coercive force Hс and the coercive force taking on asymmetric magnetic hysteresis loop Hса of the steel can be used to determine underheating and overheating during hardening but these magnetic parameters are inapplicable for hardening temperature testing. It is given that the magnetic induction taking on asymmetric magnetic hysteresis loop Brа and the magnetic induction ВδmH of the magnetic field strength of maximum difference δmH along the axis Н can give measurement sensitivity more than 40 % per 100 °C in low temperature (under 350 °C) tempering testing.

scholarly journals Влияние отжига в постоянном магнитном поле на магнитные свойства сплавов железо--галлий

2020 ◽  
Vol 62 (10) ◽  
pp. 1578
Author(s):  
В.А. Лукшина ◽  
Д.А. Шишкин ◽  
А.Р. Кузнецов ◽  
H.В. Ершов ◽  
Ю.Н. Горностырев
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Residual Induction ◽  
Dc Magnetic Field ◽  
Saturation Induction ◽  
Field Annealing ◽  
Gallium Content

The concentration dependence of the magnetic properties of iron alloys with 3 – 25 at.% gallium has been studied. It is shown that with increasing gallium content, saturation induction decreases monotonically, but coercive force shows a stepped increase with a jump from 85 to 135 A/m between 12 and 15 at.% Ga. The effect of annealing in a dc magnetic field (magnetic field annealing (MFA)) on the behavior of residual induction and coercive force in samples containing from 3 to 18 at.% of gallium was investigated. After the MFA, in the alloy a magnetic anisotropy is induced: magnetic hysteresis loops become narrower, the residual induction increases and the coercive force decreases. The MFA efficiency reaches a maximum when the gallium content is at 15 – 18 at.%. The features of the structural state in iron-gallium alloys and their role in the formation of the magnetic properties during annealing in the dc magnetic field are discussed.

Structural and Magnetic Hysteresis Properties of Co-Zr Substituted Hexagonal Barium Ferrites

2015 ◽  
Vol 7 (1) ◽  
pp. 1346-1351
Author(s):  
Ch.Gopal Reddy ◽  
Ch. Venkateshwarlu ◽  
P. Vijaya Bhasker Reddy
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Hysteresis ◽  
Grain Morphology ◽  
Hexagonal Structure ◽  
Ion Composition ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
Barium Ferrites ◽  
Xrd Patterns

Co-Zr substituted M-type hexagonal barium ferrites, with chemical formula BaCoxZrxFe12-2xO19 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), have been synthesized by double sintering ceramic method. The crystallographic properties, grain morphology and magnetic properties of these ferrites have been investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirm the single phase with hexagonal structure of prepared ferrites. The magnetic properties have been investigated as a function of Co and Zr ion composition at an applied field in the range of 20 KOe. These studies indicate that the saturation magnetization (Ms) in the samples increases initially up to the Co-Zr composition of x=0.6 and decreases thereafter. On the other hand, the coercivity (Hc) and Remanent magnetization (Mr) are found to decrease continuously with increasing Co-Zr content. This property is most useful in permanent magnetic recording. The observed results are explained on the basis of site occupation of Co and Zr ions in the samples.

Physical methods of research and monitoring

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 35-44
Author(s):  
S. G. Sandomirski
Keyword(s):  
Heat Treatment ◽  
Coercive Force ◽  
Remanent Magnetization ◽  
Structural Changes ◽  
Mechanical Load ◽  
Magnetic Hysteresis ◽  
Steel Structures ◽  
Magnetic Characteristics ◽  
Magnetic Parameters ◽  
Saturation Intensity

The main magnetic parameters sensitive to the structure of steels are the parameters of their saturation loop of magnetic hysteresis: the coercive force Hcs and remanent magnetization Mrs. The saturation magnetization or saturation intensity Mr is most sensitive to the phase composition of steels. The variety of steel grades and modes of technological treatment (e.g., heat treatment, mechanical load) determined the use of magnetic structurescopy and magnetic characteristics — the coercive force Hc, remanent magnetization Mr , and specific hysteresis losses Wh on the subloops of the magnetic hysteresis of steels — as control parameters in diagnostics of the stressed and structural states of steel structures and pipelines. It has been shown that changes in Hc, Mr , and Wh are more sensitive to structural stresses and structures of steels than the parameters of the saturation hysteresis loop of magnetic hysteresis (Hcs, Mrs, and Mrs). The formulas for calculating Hc, Mr and Wh are presented to be used for estimation of changes in the parameters upon heat treatment of steels. Features of the structural sensitivity of the subloop characteristics and expediency of their use for magnetic structural and phase analyzes are determined. Thus, the range of changes in Ìr attributed to the structural changes in steels upon gradual Hm decrease is many times wider compared to the range of possible changes in Mrs under the same conditions. Conditions (relations between the magnetic parameters) and recommendations regarding the choice of the field strength Hm are given which provide the justified use of Hc, Mr and Wh parameters in magnetic structurescopy

Easy Axis Spin-Flop in ε-Phase In-Doped Iron (III) Oxide Nanowires

2015 ◽  
Vol 233-234 ◽  
pp. 558-561
Author(s):  
A.I. Dmitriev ◽  
O.V. Koplak ◽  
Asuka Namai ◽  
Hiroko Tokoro ◽  
Shinichi Ohkoshi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Room Temperature ◽  
Easy Axis ◽  
Sharp Decrease ◽  
Oxide Nanowires ◽  
Spin Flop Transition ◽  
Ε Phase

This work reports study of magnetic properties of the ε-In0.24Fe1.76O3 nanowires possessing 6 kOe coercive force at room temperature. Freezing of the sample below 190 K causes sharp decrease of the coercive force and magnetization of nanowires driven by the easy axis spin-flop transition.

A Study on The Phase Transformation and Exchange-Coupling of (Nd0 95La0 05)9 5FebalCo5Nb2B10.5 Nanocomposites

1999 ◽  
Vol 577 ◽  
Author(s):  
Q. Chen ◽  
B. M. Ma ◽  
B. Lu ◽  
M. Q. Huang ◽  
D. E. Laughlin
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Phase Transformation ◽  
Thermal Treatment ◽  
Grain Growth ◽  
Exchange Coupling ◽  
Phase Distribution ◽  
Maximum Energy ◽  
Treatment Temperature ◽  
Phase Identification

ABSTRACTThe phase transformation and the exchange coupling in (Ndo095Lao005)9.5FebaICOsNb 2BI05 have been investigated. Nanocomposites were obtained by treating amorphous precursors at temperatures ranging from 650TC to 9500C for 10 minutes. The magnetic properties were characterized via the vibrating sample magnetometer (VSM). X-ray diffraction (XRD), thermomagnetic analysis (TMA), and transmission electron microscopy (TEM) were used to perform phase identification, measure grain size, and analyze phase distribution. The strength of the exchange coupling between the magnetically hard and soft phases in the corresponding nanocomposite was analyzed via the AM-versus-H plot. It was found that the remanence (Br), coercivity (Hci), and maximum energy product (BHmax) obtained were affected by the magnetic phases present as well as the grain size of constituent phases and their distribution. The optimal magnetic performance, BHm, occurred between 700°C to 750°C, where the crystallization has completed without excessive grain growth. TMA and TEM indicated that the system was composed of three phases at this point, Nd2(Fe Co) 14B, ca-Fe, and Fe3B. The exchange coupling interaction among these phases was consistently described via the AM-versus-H plot up to 750°C. The Br, Hci, and BHmax degraded severely when the thermal treatment temperature increased from 750°C. This degradation may be attributed to the grain growth of the main phases, from 45 to 68nm, and the development of precipitates, which grew from 5nm at 750°C to 12nm at 850°C. Moreover, the amount of the precipitates was found to increase with the thermal treatment temperatures. The precipitates, presumably borides, may cause a decrease in the amount of the a-Fe and Fe 3B and result in a redistribution of the Co in the nanocomposites. The increase of the Co content in the Nd 2(Fe Co) 14B may explain the increase of its Curie temperature with the thermal treatment temperatures. In this paper, we examine the impacts of these factors on the magnetic properties of (Ndo 95Lao 05)9 5FebaICosNb2B10.5 nanocomposite.

Effects of Magnetic Powder Loading on Mechanical Properties and Magnetic Properties of Natural Rubber

2006 ◽  
Vol 45 ◽  
pp. 1423-1428
Author(s):  
Somsak Woramongconchai ◽  
Chatchawan Lohitvisat ◽  
Aree Wichainchai
Keyword(s):  
Mechanical Properties ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Natural Rubber ◽  
Barium Ferrite ◽  
Maximum Energy ◽  
Magnetic Powder ◽  
Elongation At Break ◽  
Maximum Energy Product ◽  
Energy Product

The effect of magnetic powders and powders loading on magnetic properties and mechanical properties of magnetic rubbers were studied. The natural rubber with magnetic powders, Barium ferrite, Neodymium iron boron, were used as starting materials to prepare magnetic rubbers. Barium ferrite (BaO.6F2O3) powders had been sintered at 1285 oC for 30 hours to improve its crystal structure. The physical properties of magnetic rubbers, residual flux density (Br), coercive force (Hc), maximum energy product (BHmax), hardness and density, had a trend to increase as enhancing magnetic powders loading. However, some properties such as, intrinsic coercive force (Hci), tensile strength and elongation at break, had a trend to decrease when the magnetic powder loading was increased. Magnetic properties of the anisotropic type, sintered powders, were higher than isotropic type, non-sintered powders, except the Hci because anisotropic magnetic rubber indicated crystal orientation in the same direction.

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