Microstructure development in nickel zinc ferrites

Download

index.pdf

Date

2005

Author

Okatan, Mahmut Barış

Metadata

Show full item record

Item Usage Stats

43
views

17
downloads

Nickel zinc ferrites (NZF) have been considered as one of the basic components in high frequency electromagnetic applications especially in the field of telecommunications. In the present study, the aim was to produce high quality nickel zinc ferrite ceramics at low soaking temperatures. For this purpose, conventional ceramic manufacturing method based on mixed oxide precursors was followed using calcium fluoride, CaF2, as sintering additive. During the sintering studies, it was noticed that both the microstructure and the electromagnetic properties of the NZF ceramics were modified to a great extent by CaF2. Therefore, material characterization studies involving microstructural, dielectric and magnetic properties were conducted with respect to CaF2 content of ceramics and soak duration. The results showed that due to the presence of CaF2 in ceramics, significant improvements were achieved not only in kinetics of sintering but also in the parameters; DC electrical resistivity, dielectric constant and dielectric loss factor. For example, 1.0 wt% CaF2 added NZF ceramic produced in this study had a DC electrical resistivity of 1011 ?-cm which was أ100,000ؤ times bigger than the one attained in pure NZF ceramic. On the other hand, the dielectric constant exhibited a flat behavior up to 40 MHz with a value around 16. In addition, no resonance peak was observed in dielectric loss factor spectra, and the typical values of dielectric loss factor lied below 0.01. Besides the achievements mentioned, the magnetic properties such as relative magnetic loss factor and hysteresis parameters were also improved.

Subject Keywords

Magnetism.

URI

http://etd.lib.metu.edu.tr/upload/3/12606924/index.pdf
https://hdl.handle.net/11511/15662

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Thermoluminescence properties of fluorescent materials used in commercial lamps Bulur, Enver; Wieser, A; Figel, M; Ozer, AM (1996-01-01) The dosimetric properties of eight different fluorescent materials (FM) used in production of commercial fluorescent lamps were studied by thermoluminescence (TL). Taking into account the criteria for TL phosphors to be useful for radiation dosimetry, radiation sensitivity, thermal stability, shape of the glow curves, and effect of incandescence, UV and daylight on irradiated and non irradiated material were investigated. It was observed that most of the material can be used for radiation doses from 10 mu G...
Multi-frequency electrical conductivity imaging via contactless measurements Özkan, Koray Özdal; Gençer, Nevzat Güneri; Department of Electrical and Electronics Engineering (2006) A multi-frequency data acquisition system is realized for subsurface conductivity imaging of biological tissues. The measurement procedures of the system at different frequencies are same. The only difference between the single frequency experiments and the multi-frequency experiments is the hardware, i.e. the sensor and the power amplifier used in the single frequency experiments was different than that were used in the multi-frequency experiments. To avoid confusion the measurement system with which the s...
An Electromagnetic Micro-Power Generator for Low Frequency Vibrations with Tunable Resonance Türkyılmaz, Serhan; Muhtaroglu, A.; Külah, Haluk (2011-09-07) This paper presents an electromagnetic (EM) micro-power generator with tunable resonance frequency which can harvest energy from low frequency environmental vibrations. The reported power generator up-converts low frequency environmental vibrations before mechanical-to-electrical energy conversion by utilizing two diaphragms with different resonance frequencies. Power is generated through electromagnetic induction by a magnet attached to the low frequency diaphragm, and a 50 turn, 2.1 Omega coil, and a magn...
Optically stimulated luminescence from quartz measured using the linear modulation technique Bulur, Enver; Murray, A.S. (2000-12-15) The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonically decreasing signal, linearly increasing the stimulation power gives peaks in the signal as a function of time. In cases where the OSL signal contains more than one component, the linear increase in power of the st...
Infrared (IR) stimulated luminescence from feldspars with linearly increasing excitation light intensity Bulur, Enver (1999-01-01) IR stimulated luminescence signal from potassium and sodium feldspars were studied by linearly increasing the excitation power from zero to a maximum value during the readout. The peak shaped signals observed in both feldspars could be approximated using a linear combination of three first-order components as deduced by curve fitting. The thermal and radiation dose dependent behavior of the IR-stimulated OSL curves were also studied. (C) 1999 Elsevier Science Ltd. All rights reserved.

Citation Formats

M. B. Okatan, “Microstructure development in nickel zinc ferrites,” M.S. - Master of Science, Middle East Technical University, 2005.