scholarly journals Impact of ZrO2 Additive on Microstructure, Magnetic Properties, and Temperature Dependence of the Initial Permeability of LiTiZn Ferrite Ceramics

2021 ◽  
Author(s):  
Andrey Malyshev ◽  
Anna B. Petrova ◽  
Anatoly P. Surzhikov
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Defect Structure ◽  
Initial Permeability ◽  
Experimental Temperature ◽  
Mathematical Treatment ◽  
Experimental Temperature Dependence ◽  
Average Grain Size ◽  
Soft Ferrite ◽  
Microstructure And Magnetic Properties

Abstract The effect of the diamagnetic ZrO2 addition on the microstructure and magnetic properties of LiTiZn ferrite ceramics, including the shape and parameters of the temperature dependence of the initial permeability, has been investigated. The defect structure of ferrite ceramic samples is assessed according to our earlier proposed method based on mathematical treatment of the experimental temperature dependencies of the initial permeability. The method is recommended for defects monitoring of soft ferrite ceramics and ferrite products. It was found that the defect structure of ferrite ceramics increased by 350% with an increase in the concentration of the ZrO2 additive in the range of (0–0.5) wt.%. In this case, for the same samples, the increase in the true physical broadening of reflections is only 20%, and the coercive force by 50%. Simultaneously, the maximum of the experimental temperature dependence of the initial permeability dropped by 45%. The microstructure of all samples is characterized with a similar average grain size according to the SEM data. However, samples with the 0.5wt.% of ZrO2 are characterized by the formation of conglomerates. A linear relationship was obtained between the defect structure and the width of the reflections, which indicates that this parameter is related to the elastic stress of ferrite ceramics.

EFFECT OF COPPER OXIDE ON THE GRAIN GROWTH AND INITIAL PERMEABILITY OF Mg–Cu–Zn FERRITES

2010 ◽  
Vol 24 (02) ◽  
pp. 169-182
Author(s):  
M. MANJURUL HAQUE ◽  
M. HUQ ◽  
SYED FARID UDDIN FARHAD ◽  
JASIM UDDIN KHAN ◽  
M. A. HAKIM
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Grain Growth ◽  
Spinel Phase ◽  
Initial Permeability ◽  
Cu Content ◽  
Average Grain Size ◽  
Zn Ferrite ◽  
Effect Of Copper ◽  
Microstructure And Magnetic Properties

The microstructure and magnetic properties of Mg – Cu – Zn ferrites prepared by using solid-state reaction method have been investigated. X-ray diffraction (XRD), a scanning electron microscope (SEM), impedance analyzer and a vibrating sample magnetometer (VSM) were utilized in order to study the effect of copper substitution and its impact on the crystal structure, grain size, microstructure and magnetic properties of the Mg – Cu – Zn ferrite. The formation of cubic spinel phase was identified using XRD technique. The microstructures of the samples show that the grain growth is greatly enhanced by the addition of CuO which is attributed to the liquid phase during sintering. The average grain size (Dm) increases significantly with increasing Cu content. The initial permeability (μ') of the samples increases appreciably with increasing Cu content which is attributed to the increase of grain size and density of the samples. The resonance frequency (fr) of the samples shifts toward the lower frequency as the Cu content increases. The sharp fall of μ' in μ'-T curves is observed for all the samples which indicate the homogeneity of the samples. The saturation magnetization (Ms) of the Mg – Cu – Zn ferrites increases slightly with increasing Cu concentration.

MICROSTRUCTURE AND MAGNETIC PROPERTIES OF NANOSTRUCTURED Al2O3-20vol%Fe70Co30 COMPOSITE PREPARED BY HIGH ENERGY MECHANICAL MILLING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1383-1388 ◽  
Author(s):  
MASLEEYATI YUSOP ◽  
DELIANG ZHANG ◽  
MARCUS WILSON ◽  
NICK STRICKLAND
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
Milling Time ◽  
High Energy ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Alloy Particles ◽  
Average Grain Size ◽  
Microstructure And Magnetic Properties

Al 2 O 3-20 vol % Fe 70 Co 30 composite powders have been prepared by high energy ball milling a mixture of Al 2 O 3 powder and Fe 70 Co 30 alloy powder. The Fe 70 Co 30 alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe 70 Co 30 alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al 2 O 3 matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.

scholarly journals Effect of Mechanical Load on Defects Level in Soft Ferrite Ceramics

2018 ◽  
Vol 186 ◽  
pp. 02010
Author(s):  
A.B. Petrova ◽  
A.V. Malyshev ◽  
A.P. Surzhikov
Keyword(s):  
Temperature Dependence ◽  
Curie Point ◽  
Room Temperature ◽  
Mechanical Load ◽  
Initial Permeability ◽  
Temperature Dependences ◽  
Four Levels ◽  
Magnetic Ring ◽  
Soft Ferrite ◽  
With Screws

The article presents the results of a study of the effect of mechanical load on the temperature dependence of the initial permeability of LiTiZn soft ferrite ceramics. Regimes of mechanical load were created by a steel non-magnetic ring with screws. In this work, four levels of mechanical load were investigated: without load, with 1, 2 and 3 screws. For obtaining temperature dependences and exclude the influence of prehistory on the initial permeability, the samples were heated to a temperature exceeding the Curie point by 50 degrees, after which they slowly cooled to room temperature. The defects level was determined by the ratio of the parameters β / α of the phenomenological expression, which describes the experimental temperature dependences. It is shown that as the mechanical load increases, the defects level of ferrite ceramics increases, and after load removing, it returns to its original level.

Temperature dependence of microstructure and magnetic properties of Co/Ti multilayer thin films

1997 ◽  
Vol 81 (11) ◽  
pp. 7301-7305 ◽  
Author(s):  
Ping Wu ◽  
E. Y. Jiang ◽  
C. D. Wang ◽  
H. L. Bai ◽  
H. Y. Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Temperature Dependence ◽  
Multilayer Thin Films ◽  
Microstructure And Magnetic Properties

Microstructure and Magnetic Properties of Fe-6.5wt%Si Alloy Obtained by Spray Forming Process

2005 ◽  
Vol 498-499 ◽  
pp. 111-118 ◽  
Author(s):  
Mário Cézar Alves da Silva ◽  
Claudemiro Bolfarini ◽  
Claudio Shyinti Kiminami
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Power Loss ◽  
Antiphase Domain ◽  
Spray Forming ◽  
Forming Process ◽  
Annealing Temperatures ◽  
Average Grain Size ◽  
Maximum Permeability ◽  
Microstructure And Magnetic Properties

Deposits of the Fe-6.5wt%Si alloy produced by spray forming were annealed at temperatures between 900 and 1300oC, during 1h in vacuum and quenched in oil at temperatures between 300 and 700oC, separately. Magnetic properties, singular microstructure and random crystallographic texture were measured. After annealing at 1250°C for 1h under vacuum, the average grain size is of 500 μm, the grain orientation is random and the magnetic properties were: power loss of 1.30 W/kg, maximum permeability of 15400 and coercive force of 40 A/m, at B=1 T, f=60 Hz by using 0.60 mm thick rings for all studied samples. Higher annealing temperatures cause no decreasing of these properties. After quenched at 700°C, an improvement the magnetic properties where detected due to antiphase domain B2 growth. The magnetic properties were: power loss of 1.59 W/kg, maximum permeability of 12300 and coercive force of 76 A/m, at B=1 T, f=60 Hz.

Microstructure and Magnetic Properties of Microwave Sintered Ni0.5Zn0.5Fe2O4 Ferrite

2013 ◽  
Vol 328 ◽  
pp. 705-709
Author(s):  
Yuan Dong Peng ◽  
Qing Lin Xia ◽  
Li Ya Li ◽  
Ming Lou ◽  
Jing Zhi Hu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Microwave Sintering ◽  
Initial Permeability ◽  
Soaking Time ◽  
X Ray ◽  
Intrinsic Coercivity ◽  
Conventional Sintering ◽  
Maximum Permeability ◽  
Sintering Method ◽  
Microstructure And Magnetic Properties

Ni0.5Zn0.5)Fe2O4 ferrite has been sintered via microwave irradiation. The structural, component and magnetic properties of NiZn ferrite was determined by SEM, X-ray powder diffraction (XRD) and automatic hysteresis loop magnetometer. Results showed that the material sintered by microwave energy at 1220°C for 20min had a high purity (Ni0.5Zn0.5)Fe2O4 phase. The sample obtained magnetic properties of intrinsic coercivity 222A/m, saturation magnetization 332mT, initial permeability 0.20mH/m and maximum permeability 0.58mH/m. Compared with conventional sintering method, microwave sintering of NiZn ferrite is more efficient and reducing soaking time.

Investigation of Hard Magnetic Behaviors for Nd-Fe-B Based Magnets Prepared by Hydrogen Decrepitation Technique

2005 ◽  
Vol 475-479 ◽  
pp. 2181-2184
Author(s):  
Bo Li ◽  
Dongling Wang ◽  
Bing Lin Guo ◽  
Xiaojun Yu ◽  
Hong Wei Qin ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Temperature Dependence ◽  
Field Dependence ◽  
Nucleation Mechanism ◽  
Main Phase ◽  
Average Grain Size ◽  
Hydrogen Decrepitation ◽  
Hard Magnetic Properties ◽  
Magnetizing Field

In the present work, we investigated the hard magnetic properties of Nd-Fe-B magnets prepared by the decrepitation technique. The microstructure of (Nd0.935Dy0.065)14.5Fe79.4B6.1 HD - magnet was observed and the average grain size is about 6-15 µm. The HD alignment degree f is about 93%. Most rich-Nd phase can be found at grain boundaries of main phase, but a few rich – Nd phase occurs within main phase grains. The magnetizing field dependence of the hardmagnetic properties for the (Nd0.935Dy0.065)14.5Fe79.4B6.1 were investigated. The value of magnetizing field for the saturation coercivity is smaller than the value of the saturation coercivity, showing that the coercivity for the (Nd0.935Dy0.065)14.5Fe79.4B6.1 HD-magnet is controlled by the nucleation mechanism. Meanwhile, the temperature dependence of coercivity for HD magnet Nd14.5Fe79.4B6.1 was analyzed.

Influence of SiO2 Additive on the High-Frequency Magnetic Properties of Sr-Doped Co2Z Hexaferrite

2014 ◽  
Vol 787 ◽  
pp. 332-337
Author(s):  
Li Yun Gan ◽  
Ying Li Liu ◽  
Yu Wang ◽  
Kai Yang ◽  
Huai Wu Zhang
Keyword(s):  
Magnetic Properties ◽  
Quality Factor ◽  
High Frequency ◽  
Communication Systems ◽  
Initial Permeability ◽  
Magnetic Characteristics ◽  
Quality Factors ◽  
High Quality ◽  
Average Grain Size ◽  
Q 14

In this work, SiO2has been selected to be introduced into the system to improve the high-frequency magnetic properties of Ba1.5Sr1.5Co2Fe24O41hexaferrites. The influence of SiO2additive on the phase composition, microstructures and high-frequency magnetic properties of the samples prepared by solid-state reaction were investigated. The results indicate that the major phase of doped samples is Z-type ferrite. The addition of SiO2causes a decrease of the average grain size. Permeability measurements indicate that SiO2doping significantly improves the magnetic characteristics of those samples. With the doping content of SiO2increasing from 0 to 8wt%, the initial permeability decreases from 5.8 to 2.6, and the cut-off frequency rises up from 1.5GHz to over 1.8GHz. Meanwhile, the quality factor of the samples sintered at 1200°C varies with the SiO2content, and a maximum quality factor at 1GHz of Q=14 was found for x=4wt%. The improvements of magnetic properties and the high quality factors are crucial for applications of Z-type hexaferrites in high-frequency communication systems.

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