Influence of Atomic Doping on Thermal Stability of Ferrite Nanoparticles—Structural and Magnetic Studies

In this paper, a series of experiments are reported where ferrite nanoparticles were synthesized with different substitution percentages (5, 10, 15, or 20%) of Fe2+ by Co2+, Mn2+, or Ni2+ ions. Afterwards, the prepared nanoparticles were thermally treated between 50 and 500 °C in air for 24 h in order to observe how doping influences the oxidation process induced by temperature elevation and access to O2. Nanoparticles were imaged before and after thermal treatment by transmission electron microscopy and were analyzed by X-ray diffraction, vibrating sample magnetometry, and Mössbauer spectroscopy. Presented studies reveal that the amount and kind of doped transition metals (of replaced Fe2+) strongly affect the oxidation process of ferrite nanoparticles, which can govern the application possibility. Each transition element suppresses the oxidation process in comparison to pure Fe-oxides, with the highest impact seen with Ni2+.

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Thermolysis of sprayed suspensions for obtaining highly spinel ferrite nanoparticles

Journal of the Belarusian State University Chemistry ◽

10.33581/2520-257x-2019-1-14-21 ◽

2019 ◽

pp. 14-21

Author(s):

Elena G. Petrova ◽

Yana A. Shavshukova ◽

Dzmitry A. Kotsikau ◽

Kazimir I. Yanushkevich ◽

Konstantin V. Laznev ◽

...

Keyword(s):

Annealing Temperature ◽

Spinel Ferrite ◽

Ferrite Nanoparticles ◽

Specific Magnetization ◽

X Ray Diffraction ◽

Crystallinity Degree ◽

Insulating Layer ◽

X Ray ◽

Transmission Electron ◽

Before And After

Thermal treatment of ferrite magnetic nanoparticles in NaCl matrix gives an opportunity to increase their specific magnetization with preservation of nanoscale size. Composite materials based on mixed ferrites Co0.65Zn0.35Fe2O4 and Mg 0.5Zn0.5Fe2O4 were synthesized by spray-drying of aqueous suspensions in presence of NaCl and annealed at 300 –900 °C. The microstructure and phase composition of nanoparticles before and after annealing were studied by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction analysis and IR spectroscopy. The magnetic properties of nanoparticles were estimated using a ponderomotive method of measuring the specific magneti zation at room temperature in a magnetic field with an induction of 0.86 T. The increase of the annealing temperature up to 900 °C was established to lead to the increase in the specific magnetization of ferrites – from 32.79 to 91.3 emu/g (Co0.65Zn0.35Fe2O4) and from 2.76 to 22.31 emu/g (Mg 0.5 Zn 0.5Fe2O4) due to recrystallization processes and increase of crystallinity degree of the ferrites. Due to the NaCl insulating layer, the particle size increases just slightly (from ~ 10 nm before annealing to ~ 60 nm after annealing at 900 °C). This method is effective for substantial increase in specific magnetization of ferrite nanoparticles with preservation of their nanoscale size.

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Thermal treatment of magnetite nanoparticles

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.6.143 ◽

2015 ◽

Vol 6 ◽

pp. 1385-1396 ◽

Cited By ~ 27

Author(s):

Beata Kalska-Szostko ◽

Urszula Wykowska ◽

Dariusz Satula ◽

Per Nordblad

Keyword(s):

Thermal Stability ◽

Thermal Treatment ◽

Magnetite Nanoparticles ◽

Surface Characteristics ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Transmission Electron ◽

Before And After ◽

Thermal Stability Of

This paper presents the results of a thermal treatment process for magnetite nanoparticles in the temperature range of 50–500 °C. The tested magnetite nanoparticles were synthesized using three different methods that resulted in nanoparticles with different surface characteristics and crystallinity, which in turn, was reflected in their thermal durability. The particles were obtained by coprecipitation from Fe chlorides and decomposition of an Fe(acac)3 complex with and without a core–shell structure. Three types of ferrite nanoparticles were produced and their thermal stability properties were compared. In this study, two sets of unmodified magnetite nanoparticles were used where crystallinity was as determinant of the series. For the third type of particles, a Ag shell was added. By comparing the coated and uncoated particles, the influence of the metallic layer on the thermal stability of the nanoparticles was tested. Before and after heat treatment, the nanoparticles were examined using transmission electron microscopy, IR spectroscopy, differential scanning calorimetry, X-ray diffraction and Mössbauer spectroscopy. Based on the obtained results, it was observed that the fabrication methods determine, to some extent, the sensitivity of the nanoparticles to external factors.

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Characterization of ferrite nanoparticles for preparation of biocomposites

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.8.127 ◽

2017 ◽

Vol 8 ◽

pp. 1257-1265 ◽

Cited By ~ 7

Author(s):

Urszula Klekotka ◽

Magdalena Rogowska ◽

Dariusz Satuła ◽

Beata Kalska-Szostko

Keyword(s):

Chemical Method ◽

Ferrite Nanoparticles ◽

Chemical Activity ◽

Nominal Composition ◽

X Ray Diffraction ◽

Wet Chemical Method ◽

X Ray ◽

Transmission Electron ◽

Wet Chemical

Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11–16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with –COOH and –NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker. In the second one, direct bonding of such nanoparticles with a bioparticle was studied. In subsequent steps, the nanoparticles were immobilized with enzymes such as albumin, glucose oxidase, lipase and trypsin as a test bioparticles. The characterization of the nanoparticles was acheived by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and Mössbauer spectroscopy. The effect of the obtained biocomposites was monitored by Fourier transform infrared spectroscopy. The obtained results show that in some cases the use of glutaraldehyde was crucial (albumin).

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Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

MRS Proceedings ◽

10.1557/proc-514-191 ◽

1998 ◽

Vol 514 ◽

Cited By ~ 1

Author(s):

M. F. Wu ◽

A. Vantomne ◽

S. Hogg ◽

H. Pattyn ◽

G. Langouche ◽

...

Keyword(s):

Thermal Stability ◽

Ion Beam ◽

Hexagonal Structure ◽

Orthorhombic Structure ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Good Crystalline Quality ◽

Ion Beam Synthesis ◽

Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

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Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

Journal of Nanomaterials ◽

10.1155/2013/650725 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 20

Author(s):

Mashael Alshabanat ◽

Amal Al-Arrash ◽

Waffa Mekhamer

Keyword(s):

Electron Microscopy ◽

Thermal Stability ◽

Solution Method ◽

Sonication Time ◽

X Ray Diffraction ◽

Transmission Electron ◽

Polystyrene Matrix ◽

Before And After ◽

Silicate Layers ◽

Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

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Immobilization of hemoglobin on stable mesoporous multilamellar silica vesicles and their activity and stability

Journal of Materials Research ◽

10.1557/jmr.2005.0360 ◽

2005 ◽

Vol 20 (10) ◽

pp. 2682-2690 ◽

Cited By ~ 15

Author(s):

Yufang Zhu ◽

Weihua Shen ◽

Xiaoping Dong ◽

Jianlin Shi

Keyword(s):

Thermal Stability ◽

Pore Size ◽

X Ray Diffraction ◽

X Ray ◽

Practical Applications ◽

Silica Material ◽

Transmission Electron ◽

Mesoporous Support ◽

Adsorption Desorption ◽

Thermal Stability Of

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.

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Synthesis of Fe2O3/CNTs for the Fast Removal of Tetracycline from Aqueous Solutions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.915-916.933 ◽

2014 ◽

Vol 915-916 ◽

pp. 933-941 ◽

Cited By ~ 3

Author(s):

Zhong Jie Zhang ◽

Chang Yu Lu ◽

Wei Huang ◽

Wei Sheng Guan ◽

Yue Xin Peng

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Magnetic Measurements ◽

Ferrite Nanoparticles ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Wide Range ◽

Fast Removal ◽

Scanning Electron

The effective remove to tetracycline still remains a big challenge for scientists. In this work, we used a new method for preparing functional magnetic CNTS with ferrite nanoparticles. A wide range of techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and magnetic measurements were applied to characterize the obtained Fe2O3/CNTs. Moreover, we have also studied the properties of adsorbent to tetracycline. In addition, we have found that the Fe2O3/CNTs are better reusable adsorbent than other traditional adsorbents by magnetic separation recycling method.

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Modification of clays with styrenic ionic liquid by Synthesis of in-situ Polystyrene Nanocomposite

e-Polymers ◽

10.1515/epoly-2013-0131 ◽

2013 ◽

Vol 13 (1) ◽

Author(s):

Mohammad Galehassadi ◽

Fatemeh Hosseinzadeh ◽

Mehrdad Mahkam

Keyword(s):

Electron Microscopy ◽

Ionic Liquid ◽

Clay Nanocomposites ◽

X Ray Diffraction ◽

X Ray ◽

Modified Montmorillonite ◽

Transmission Electron ◽

Insitu Polymerization ◽

Thermal Stability Of

Abstract Nanocomposites of polystyrene (PS) was prepared with new styrenic ionic liquid, N-(4-vinyl benzyl)-(N,N-dimethylamino) pyridinium chloride[VBMAP], surfactants used as organic modifications for the clays. Sodium montmorillonite (Na-MMT) was successfully modified by [VBMAP] to become OMMT through cation exchange technique which is shown by the increase of basalspacing of clay by XRD. The composite material based on polystyrene and organo-modified montmorillonite (OMMT) was prepared by insitu polymerization and characterized. The morphology of the polymer/clay hybrids was evaluated by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites were enhanced, as evaluated by thermogravimetric analysis.

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The Microstructure of Fe7C3 Formed at 300°C by Plasma Enhanced Chemical Vapor Deposition (PECVD)

MRS Proceedings ◽

10.1557/proc-313-691 ◽

1993 ◽

Vol 313 ◽

Author(s):

H. Siriwardane ◽

P. Fraundorf ◽

J.W. Newkirk ◽

O.A. Pringle ◽

W.J. James

Keyword(s):

Oxidation Process ◽

Iron Carbide ◽

Chemical Vapor ◽

Carbon Films ◽

Corrosion And Wear ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Iron Phase ◽

Diffraction Patterns

Thin iron carbide films were prepared by introducing iron penta carbonyl (FeCO5) and hydrogen (H2) into a glow discharge. The films are of potential interest in corrosion and wear resistant applications. X-ray diffraction data of films (≈ 7000 Å thick) deposited on glass at 300°C evidenced only Fe7C3. Thinner films were required for examination by analytical and high resolution transmission electron Microscopy. Therefore, two sets of films (“thin” < 200 Å and “thick” ≈ 800 Å) were plasma-deposited on carbon or holey carbon films supported on copper grids. The thin TEM specimens exhibited a fine texture and gave rise to ring diffraction patterns, whereas the thick TEM specimens evidenced two types of structure: (i) half-Micron sized grains separated from one another by 1–2 Microns on the support, although sometimes interconnected by single crystal platelets and (ii) 300 Å grapelike clumps of 100–200 Å crystals, each individually surrounded by a 50 Å non-crystalline coating. The latter structure may result from a post-formation oxidation process which expels carbon from the iron phase into grain boundaries.

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Magnetoelectric and magnetic studies of the Bi1–xCaxFeO3 multiferrioc system

Canadian Journal of Physics ◽

10.1139/cjp-2012-0282 ◽

2014 ◽

Vol 92 (5) ◽

pp. 389-394 ◽

Cited By ~ 2

Author(s):

S.F. Mansour ◽

N.I. Abu-Elsaad ◽

T.A. Elmosalami

Keyword(s):

Room Temperature ◽

Energy Levels ◽

Resonance Field ◽

X Ray Diffraction ◽

Magnetic Studies ◽

X Ray ◽

Transmission Electron ◽

Spin Resonance ◽

Particle Size And Shape ◽

Combustion Technique

Bi1–xCaxFeO3 was prepared by the flash autocombustion combustion technique. X-ray diffraction analysis showed a Rhombohedrally distorted hexagonal perovskite structure with space group R3c. The particle size and shape were studied by transmission electron microscope. Magnetization studies at room temperature showed superparamagnetic behavior for the prepared nanoparticles. Magnetoelectric coefficient characterized as magnetic field – induced polarization was investigated. The Lande factor (g), resonance field (Br), relaxation time (τ), and the energy between two adjacent degenerate spin energy levels (ΔE) were estimated from the electron spin resonance spectra.

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