Pankaj P. Khirade

Temperature dependent viscosity of cobalt ferrite / ethylene glycol ferrofluids

In the present work, cobalt ferrite / ethylene glycol ferrofluid is prepared in 0 to 1 (in the step of 0.2) volume fraction of cobalt ferrite nanoparticles synthesized by co-precipitation method. The XRD results confirmed the formation of single phase spinel structure. The Raman spectra have been deconvoluted into individual Lorentzian peaks. Cobalt ferrite has cubic spinel structure with Fd3m space group. FT-IR spectra consist of two major absorption bands, first at about 586 cm−1 (υ1) and second at about 392 cm−1 (υ2). These absorption bands confirm the formation of spinel-structured cobalt ferrite. Brookfield DV-III viscometer and programmable temperature-controlled bath was used to study the relationship between viscosity and temperature. Viscosity behavior with respect to temperature has been studied and it is revealed that the viscosity of cobalt ferrite / ethylene glycol ferrofluids increases with an increase in volume fraction of cobalt ferrite. The viscosity of the present ferrofluid was found to decrease with increase in temperature.In the present work, cobalt ferrite / ethylene glycol ferrofluid is prepared in 0 to 1 (in the step of 0.2) volume fraction of cobalt ferrite nanoparticles synthesized by co-precipitation method. The XRD results confirmed the formation of single phase spinel structure. The Raman spectra have been deconvoluted into individual Lorentzian peaks. Cobalt ferrite has cubic spinel structure with Fd3m space group. FT-IR spectra consist of two major absorption bands, first at about 586 cm−1 (υ1) and second at about 392 cm−1 (υ2). These absorption bands confirm the formation of spinel-structured cobalt ferrite. Brookfield DV-III viscometer and programmable temperature-controlled bath was used to study the relationship between viscosity and temperature. Viscosity behavior with respect to temperature has been studied and it is revealed that the viscosity of cobalt ferrite / ethylene glycol ferrofluids increases with an increase in volume fraction of cobalt ferrite. The viscosity of the present ferrofluid was found to...

Effect of iron oxide (Fe 2 O 3 ) on the structural, optical, electrical, and dielectric properties of SrO–V 2 O 5 glasses

The oxide glass system of the composition (10 – x)SrO–xFe2O3–90V2O5, (x = 0, 2, 4, 6 and 8 mol %) were prepared by a standard melt quenching technique. The amorphous nature of the prepared glass was confirmed using X-ray diffraction technique. The infrared spectra of these glasses were recorded over a continuous spectral range (850–1500 cm–1). The density of prepared sample was obtained by the Archimedes principle. The physical parameters of the glasses were also determined with respect to the composition. Density increases from 3.10 to 3.20 g/cm3, whereas the molar volume decreases with the increase in Fe2O3 concentration. In order to study optical properties, absorption spectra were measured at room temperature. Indirect optical energy band gap, optical dielectric constant, refractive index were calculated from optical energy band gap. The refractive index decreases gradually with the increase in Fe2O3 content due to increase of bridging oxygen’s. For temperatures from 300 to 500 K, the dc conductivity increased with the increasing Fe2O3 content. The dielectric properties like dielectric constant, dielectric loss factor and dielectric loss tangent investigated at the room temperature in the frequency range of 10 kHz to 1 MHz decreases with frequency. The dielectric behavior shows strong frequency as well as composition dependence.

Rietveld refinement and electrical properties of LiTiFeO4

Nanoparticles of Ti4+ substituted lithium ferrite LiTiFeO4 were prepared by the sol-gel auto combustion method. The sintered sample was characterized by X-ray diffraction to study the structural properties. The crystallite size obtained by Scherrer formula using XRD data is 22nm. The Rietveld refinement of the obtained XRD pattern was carried out using full-proof program. The electrical measurements as DC electrical resistivity and I-V measurement were carried out by two-probe technique and I-V characteristics. The semiconducting behaviour of the investigated sample was observed. The Ohmic nature was revealed by I-V characteristic.Nanoparticles of Ti4+ substituted lithium ferrite LiTiFeO4 were prepared by the sol-gel auto combustion method. The sintered sample was characterized by X-ray diffraction to study the structural properties. The crystallite size obtained by Scherrer formula using XRD data is 22nm. The Rietveld refinement of the obtained XRD pattern was carried out using full-proof program. The electrical measurements as DC electrical resistivity and I-V measurement were carried out by two-probe technique and I-V characteristics. The semiconducting behaviour of the investigated sample was observed. The Ohmic nature was revealed by I-V characteristic.

Investigations on the synthesis, structural and microstructural characterizations of Ba1-xSrxZrO3 nanoceramics

ABSTRACT Strontium (Sr) substituted barium zirconate (Ba1-xSrxZrO3, for x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) perovskite nanoceramics were prepared by simple, easy and cost-effective sol-gel auto combustion technique using citric acid as a fuel. X-ray diffraction (XRD) patterns confirmed the formation of cubic phase structure for x = 0.0–0.6 composition with minor impurity of carbonate. However, for x = 0.8–1.0 orthorhombic distorted perovskite structure was observed. The average crystallite size (t), lattice constant (a, b and c) and other structural parameters of Sr substituted barium zirconate nanoceramics were calculated from XRD data. The average particle size was calculated by using the Debye-Scherers formula obtained to be 18–25 nm. The average crystallite size, lattice parameter, unit cell volume and X-ray density value changes when Sr2+ ions are substituted in BaZrO3 lattice, resulting in the structural variation. The microstructural studies were investigated through scanning electron microscopy (SEM) technique. SEM confirmed the homogeneous and well defined surface morphology of the synthesized samples in nano range. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of a metal oxide band (-O-Zr-O-) for all the calcined samples. The FTIR spectra confirmed that the prepared ceramics have a cubic perovskite structure for lower Sr composition, the shifting of the major band (for x = 0.8–1.0) suggests distortion in geometry. Compositional stoichiometry was confirmed by energy dispersive spectrum (EDS) analysis.