Quantitative methods for nanopowders characterization

Without any surfactant, antiferromagnetic Co 3 O 4 nanoparticles were synthesized successfully for the first time by means of an oxidation-reduction method with cobalt sulfate as starting material, which was oxidized to cobalt salt by NaNO 3 after alkalinizing with NaOH. Morphological, structural, spectroscopic and magnetic characterization of the product were done by SEM, TEM, XRD, and VSM, respectively. The average crystallite size (on the base of line profile fitting method), D and σ, is estimated as 30 ± 6 nm. Some anomalous magnetic properties and their enhanced effect have been observed in Co 3 O 4 antiferromagnetic nanocrystallites, including a bias field, coercivity, permanent magnetic moments and an open loop. These phenomena are attributed to the unidirectional anisotropy which is caused by the exchange coupling between AFM and FM layers, the existence of the spin glass like surface spins of Co 3 O 4 nanoparticles due to size effects and surface-area effect.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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“…The mean size of nanoparticles was estimated from the diffraction pattern using Eq. 1 given in Wejrzanowski et al [33] and Pielaszek [34].…”

Section: Xrd Analysismentioning

confidence: 98%

Synthesis of Co3O4 nanoparticles by oxidation-reduction method and its magnetic characterization

et al. 2009

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“…3 The mean size of the crystallites was estimated from the diffraction pattern by line profile fitting method using the equation (1) given in [41,42]. The line profile, shown in Fig.…”

Section: Xrd Analysismentioning

confidence: 99%

The Effect of Condensation on the Morphology and Magnetic Properties of Modified Barium Hexaferrite (BaFe12O19)

et al. 2011

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Abstract:We present a comparison for the effect of condensation on the morphology and magnetic properties of oleic acid modified BaFe12O19 nanoparticles. Two different samples of BaFe12O19 nanoparticles were synthesized by dehydration (Z1) and rotary evaporation (Z2) method, respectively. Oleic acid was used as the surface modification agent to observe the morphological and magnetic changes. The nanoparticles were analyzed by XRD, FTIR, TGA, SEM, and VSM techniques for structural and physicochemical characteristics. Crystallographic analysis reveals the phase as hexaferrite and the average crystallite size of Z1 and Z2 is 21±3 nm and 17±2 nm, respectively. Rotary evaporator accelerates the condensation process in viscous gel (Z2). Due to the use of rotary evaporator, the coating with oleic acid for Z2 product has been accomplished very well, as compared with Z1. As a result, saturation magnetization of Z2 sample is much lower than that of Z1 sample.

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“…Based on the combined measurements of SSA BET and density (1) it was possible to report the variation of mean equivalent sphere size of particles in the nanopowder for all compositions investigated (Fig. 3b) [36]. It should be noted that particle density was found to monotonically decrease with % AlO(OH) in the system (Fig.…”

Section: Nanopowders Synthesis and Characterisation Methodsmentioning

confidence: 96%

“…Particle aspect ratio or the non-sphericity increases with increasing AlO(OH) content for this composition range (from 80 to 100%). In order to test the assumption of particle size evaluation using SSA BET , another method (Scherrer method) was used [30,36]. The particle size range for selected compositions was following: 80% of AlO(OH): 18-25 nm, 90% of AlO(OH): 17-33 nm, 96% of AlO(OH): 9-17 nm, 99% of AlO(OH): 7-13 nm, and AlO(OH): 6-12 nm.…”

Section: Nanopowders Synthesis and Characterisation Methodsmentioning

confidence: 99%

Thermal and physical properties of ZrO2–AlO(OH) nanopowders synthesised by microwave hydrothermal method

Koltsov

Prześniak-Welenc

Wojnarowicz

et al. 2017

J Therm Anal Calorim

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Industrially relevant nanopowder was synthesised by microwave hydrothermal synthesis to obtain wellcontrolled composition (ZrO 2 -AlO(OH) system) which was found to determine a number of physical and thermal characteristics. This study reports variation of particle size, density, specific surface area (SSA BET ), as well as thermal behaviour of nanopowder mixtures of ZrO 2 -AlO(OH) in the whole range of compositions. It was found that the onset temperature (T on ) of physically and chemically bounded water desorption depends on the Al 3? /or AlO(OH) content. The lower content of Al 3? in the ZrO 2 -AlO(OH) system, the higher T on of physically bound water desorption. There are three distinct temperature regions for water decomposition for nanomaterials investigated in air (at approximately 50, 250 and 450°C). These temperature ranges depend on particle size and chemical composition of ZrO 2 -AlO(OH) nanopowders. Materials were divided into three groups characterised by different properties: (1) ZrO 2 with 2-12% of Al 3? , where particle sizes are from 4 to 8 nm, (2) ZrO 2 with 30-67% of AlO(OH), where particle sizes are from 10 to 13 nm, and (3) ZrO 2 with 80-99% of AlO(OH), where particle sizes are from 13 to 23 nm. AlO(OH) content determines thermal and physico-chemical properties of synthesised ZrO 2 -AlO(OH) nanopowders.

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Quantitative methods for nanopowders characterization

Cited by 204 publications

References 5 publications

Synthesis of Co3O4 nanoparticles by oxidation-reduction method and its magnetic characterization

Synthesis of Co3O4 nanoparticles by oxidation-reduction method and its magnetic characterization

The Effect of Condensation on the Morphology and Magnetic Properties of Modified Barium Hexaferrite (BaFe12O19)

Thermal and physical properties of ZrO2–AlO(OH) nanopowders synthesised by microwave hydrothermal method

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