Thermal structural analysis Mössbauer and impeda

Authors: Shahid Khan Durrani S Naz M Nadeem E Ahmed M Siddique

Publish Date: 2014/09/20

Volume: 119, Issue: 1, Pages: 253-263

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Abstract

Nanocrystalline nickel ferrite and copper nickel ferrite materials were synthesized through surfactant Tween 80assisted hydrothermal reaction at low temperature using metallic copper nickel and iron as raw materials Thermogravimetric TG and differential thermal analysis DTA were used to determine the decomposition of the precursors Phase composition microstructural characterization and distribution of cations in tetrahedral and octahedral sites of crystal structure properties of synthesized ferrite materials were investigated by Xray diffraction XRD scanning electron microscopy SEM Fourier transform infrared FTIR absorption and Mössbauer spectroscopy The impedance spectroscopic studies of copper nickel ferrite sintered ceramics were carried out at room temperature TG and DTA of precursors revealed that the crystallization temperature for spinel ferrites phases formation was around 650 °C which were being synthesized through Tween 80assisted hydrothermal process in highly basic reaction at 180–200 °C for 11–13 h in PTFElined stainless steel autoclave XRD analysis and Rietveld refinement study confirm the formation of singlephase cubic spinel nickel ferrite NiFe2O4 and copper nickel ferrite Ni05Cu05Fe2O4 with cell parameters 83385 83595 Å and space group Fd3 m respectively The synthesized ferrite products showed extensive XRD line broadening and the average crystallite sizes of NiFe2O4 and Cu05Ni05Fe2O4 ferrites were in range of 21–29 nm and 18–23 nm respectively Mössbauer parameters are characteristic of substituted CuNiFe2O4 ferrite material Isothermal shrinkage characteristic and coefficient of thermal expansion were determined by dilatometry The ferrite specimens showed excellent densification at 1050 °C temperature and uniformly fine grainsintered ceramics with submicron grain size 10–18 μm were obtained after sintering at 850 and 1050 °C Sintering at 1050 °C results in the formation of depletion layer at grain boundaries which act as trapping centers for the carriers and an increase in the impedance values are conferredOne of the author Sumaira Naz wishes to thank the financial support of the Higher Education Commission HEC Pakistan through the 5000 Indigenous PhD scholarship scheme in Science and Technology Authors also wish to thank to Aurangzeb MMR Baig M Shafi M Hussain Z Ahmed Shahid Ayub and Laquit Ali for their technical and lab assistance during XRD SEM Mössbauer data collection and hydrothermal experiments

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