Papers by Keyword: Nickel-Zinc Ferrite

Abstract: The magnetic spinel phase formation in Ni_1-xZn_xFe₂O₄ (x=0.1, 0.3, 0.5) nickel-zinc ferrite synthesized from mechanically activated NiO-ZnO-Fe₂O₃ mixture was studied by thermomagnetometry method, X-ray diffraction and saturation magnetization analyses. The initial reagents were activated via milling the mixture in a planetary ball mill at 500 and 1000 rpm. The Ni-Zn ferrites were synthesized at 950 °C for 4 hours using the solid-state technology. The correlation between the results obtained using above methods of testing ferrite was revealed. It was found that the magnetic spinel phase concentration in the synthesized samples increases with an increase in the milling energy intensity of mixture. Thus, ferrite obtained from pre-activated at 1000 rpm oxides is characterized by a high concentration of nickel-zinc ferrite in their composition.

Abstract: Magnetic photocatalyst ZnO/nickel-zinc ferrite powders were synthesized by two-step method: First ,nickel-zinc ferrite powders were prepared by coprecipitation method and then ZnO /nickel-zinc ferrite composite powders were prepared by the homogeneous precipitation method. The as-prepared sample was characterized by X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM), the photocatalysis of the catalyst was evaluated with methylene blue as decomposition substance and the photocatalytic activity of the material has been tested on decomposable substrate under visible-light in the magnetic photocatalytic wastewater treatment reactor. The results demonstrate that the magnetic photocatalyst ZnO/nickel-zinc ferrite powders exhibit highly efficient visible-light-driven photocatalytic activity, the degradation rate of methylene blue is 84%.

Abstract: Electromagnetic Interference (EMI) issue is gaining more attention as the result of proliferation of electrical and electronic devices. In order to reduce the exposure to EMI, shielding and absorbing materials are often applied. This paper discussed the process of forming the nickel-zinc ferrite as one of the absorbing material by mixing the nickel nitrate, zinc nitrate and iron (III) nitrate together. X-ray diffraction, scanning electron microscopy, and dielectric measurement are carried out to reveal the characteristic of the specimen. The sintering temperature determines the formation of a pure spinal nickel-zinc ferrite and grain size.

Abstract: Ni_0.4Zn_0.6Fe₂O₄-polypropylene (PP) composites were investigated for their dielectric property which constitutes the dielectric constant , and dielectric loss factor . Nickel zinc ferrites (NZF) were prepared via the conventional solid state method and sintered at 1250 °C for 10 hours. Ni_0.4Zn_0.6Fe₂O₄ acts as filler while PP is the matrix. 5% and 25% NZF were added into the PP and blended to form NZF-PP composites. Dielectric measurements were made from room temperature to 120 °C at 20 °C intervals using the HP 4284A Precision LCR Meter at frequencies 240 Hz to 1 MHz. is almost constant and independent of frequency and temperature below 100 KHz before decreasing showing dispersion probably due to space charge or interfacial polarization. Distinct relaxation loss peaks can be seen emerging at about 100 KHz shifting towards the higher frequency with increasing temperature. Generally, increasing the content of filler improve the dielectric strength of the composite. Thus, addition of NZF enhances the dielectric properties of NZF-PP composite.

Abstract: Ni _0.6-xZn _0.4 Mg _x Fe ₂ O ₄ were synthesized by sol-gel auto-combustion method with Zn(NO ₃.) 2 •6H2_O. , Ni(NO ₃.) )2•6H2_O. , Mg(NO ₃.) )2•6H2_O. , Fe(NO ₃.) )3•9H2_O. , C_OOO2. and NH₃•H2_O. X-ray diffraction (XRD) analysises show that the sample is single phase and the doping of magnesium makes no difference to nickel-zinc ferrite’s crystal structure; nickel-zinc ferrite has formed after auto-combustion. Scanning electron microscope analysises show that after sintered the sample’s size is more even and the doping of magnesium makes the size smaller and more even too.