scholarly journals Thermolysis of sprayed suspensions for obtaining highly spinel ferrite nanoparticles

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.

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

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 100
Author(s):  
Urszula Klekotka ◽  
Dariusz Satuła ◽  
Simo Spassov ◽  
Beata Kalska-Szostko
Keyword(s):  
Oxidation Process ◽  
Transition Element ◽  
Ferrite Nanoparticles ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
X Ray ◽  
Transmission Electron ◽  
Before And After ◽  
Series Of Experiments ◽  
Thermal Stability Of

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+.

scholarly journals Adsorption and gas sensing properties of CuFe2O4 nanoparticles

2019 ◽  
Vol 37 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Mohammad Abu Haija ◽  
Georgia Basina ◽  
Fawzi Banat ◽  
Ahmad I. Ayesh
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Grid Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Gas Sensing Properties

AbstractSpinel ferrite nanoparticles in the form CuFe2O4 were tested for gas sensing applications. Nanoparticles pressed in a disk form were used to construct conductometric gas sensors. The disk was placed between two electrical electrodes wherein the top electrode had a grid structure. The produced sensors were tested against H2S and H2 gases and they were found to be selective and sensitive to H2S concentration as low as 25 ppm. The composition of the nanoparticles was confirmed by X-ray diffraction and energy dispersive X-ray spectroscopy measurements. The crystal structure was verified by both X-ray diffraction and transmission electron microscope. The observations obtained from the experiments demonstrated the high potential of using CuFe2O4 nanoparticles for H2S sensing applications.

scholarly journals A Study of Thin Film Resistors Prepared Using Ni-Cr-Si-Al-Ta High Entropy Alloy

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ruei-Cheng Lin ◽  
Tai-Kuang Lee ◽  
Der-Ho Wu ◽  
Ying-Chieh Lee
Keyword(s):  
Annealing Temperature ◽  
Phase Evolution ◽  
Amorphous Structure ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Temperature Coefficient Of Resistance ◽  
X Ray ◽  
High Entropy ◽  
Transmission Electron ◽  
Thin Film Resistors

Ni-Cr-Si-Al-Ta resistive thin films were prepared on glass and Al2O3substrates by DC magnetron cosputtering from targets of Ni0.35-Cr0.25-Si0.2-Al0.2casting alloy and Ta metal. Electrical properties and microstructures of Ni-Cr-Si-Al-Ta films under different sputtering powers and annealing temperatures were investigated. The phase evolution, microstructure, and composition of Ni-Cr-Si-Al-Ta films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). When the annealing temperature was set to 300°C, the Ni-Cr-Si-Al-Ta films with an amorphous structure were observed. When the annealing temperature was at 500°C, the Ni-Cr-Si-Al-Ta films crystallized into Al0.9Ni4.22, Cr2Ta, and Ta5Si3phases. The Ni-Cr-Si-Al-Ta films deposited at 100 W and annealed at 300°C which exhibited the higher resistivity 2215 μΩ-cm with −10 ppm/°C of temperature coefficient of resistance (TCR).

scholarly journals Characterization of ferrite nanoparticles for preparation of biocomposites

2017 ◽  
Vol 8 ◽  
pp. 1257-1265 ◽  
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).

Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

2007 ◽  
Vol 130 ◽  
pp. 171-174 ◽  
Author(s):  
Z. Stokłosa ◽  
G. Badura ◽  
P. Kwapuliński ◽  
Józef Rasek ◽  
G. Haneczok ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray ◽  
Second Stage ◽  
Transmission Electron

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

Thermal quenching behavior of Er-doped silicon-rich SiO2 prepared by ion implantation

2004 ◽  
Vol 19 (9) ◽  
pp. 2699-2702 ◽  
Author(s):  
C.S. Zhang ◽  
H.B Xiao ◽  
Y.J. Wang ◽  
Z.J. Chen ◽  
X.L. Cheng ◽  
...  
Keyword(s):  
Silicon Nanocrystals ◽  
Annealing Temperature ◽  
Thermal Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiative Processes ◽  
Transmission Electron ◽  
Weak Intensity ◽  
Er Doped

Erbium and silicon were dual implanted into thermally grown SiO2 film on Si (110) substrates, followed by thermal treatment at 700–1200 °C for 30 min. The microstructure was studied by transmission electron microscope and x-ray diffraction. When the implanted films were annealed at T > 900 °C, the silicon nanocrystals (nc-Si) enwrapped by amorphous silicon (a-Si) could be observed. The thermal quenching behavior at λ = 1.535 μm and its relation with the annealling temperature were also investigated. With increasing annealing temperature, the portion of a-Si and the thermal quenching both decreased. Efficient luminescence from Er ions and weak intensity thermal quenching were obtained from the sample annealed at 1100 °C. The role of a-Si in non-radiative processes at T > 100 K is discussed.

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

2014 ◽  
Vol 915-916 ◽  
pp. 933-941 ◽  
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.

THE INVESTIGATION ON STABILITY AND STRUCTURAL PROPERTIES OF COHESION-BASED NANOSTRUCTURES MATERIAL

2013 ◽  
Vol 27 (27) ◽  
pp. 1350153 ◽  
Author(s):  
ALI BAHARI ◽  
REZA GHOLIPUR ◽  
MARYAM DERAKHSHI
Keyword(s):  
Annealing Temperature ◽  
Sol Gel ◽  
Growth Mode ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
X Ray ◽  
Annealing Temperatures ◽  
Atomic Force ◽  
Transmission Electron

Styrene-doped ZrLaO y nanostructures were obtained by sol–gel method low-temperature synthesis. The nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and transmission electron microscopy (TEM) techniques. The observation using SEM and TEM revealed that the ring-shaped nanostructures were very uniform. Further characterization using XRD disclosed that the cohesion of the samples was controllable with annealing temperatures in the range of 800–1500°C. Cohesion property was investigated for the samples. The cohesion increased when increasing the annealing temperature. This was linked to the reinforcement of the oxygen bound on the ZrLaO y nanostructures The shape of nanostructures showed a transformation from a ring-shaped growth mode to a hole-surfaced growth mode with increasing annealing temperature. The styrene-doped ZrLaO y nanostructures with controllable crystallinity will have great potential for various applications in fuel, cells, batteries, electronics devices and chemical sensors.

Structure of CoxAg100-x and Its Relation to GMR

1992 ◽  
Vol 286 ◽  
Author(s):  
John Q. Xiao ◽  
J. Samuel ◽  
C. L. Chien
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Composition Range ◽  
Magnetic Scattering ◽  
Granular System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Concentration

ABSTRACTWe have studied the structure of the Co-Ag granular system across the entire composition range, as well as the annealed samples, using transmission electron microscopy (TEM) and x-ray diffraction. GMR, as much as 80% at 5K and 25% at room temperature, have been observed. The absolute values of the resistivity (ρ) and the change of the resistivity (δρ) as functions of the magnetic Co concentration and the annealing temperature have been determined. A linear relation between δρ and I/rco, where rco is Co particle size, has been found. This result suggests that the magnetic scattering at the interfaces is crucial to GMR.

Sol-gel derived Ba(Mg1/3Ta2/3)O3 thin films: Preparation and structure

1997 ◽  
Vol 12 (3) ◽  
pp. 596-599 ◽  
Author(s):  
Ji Zhou ◽  
Qing-Xin Su ◽  
K. M. Moulding ◽  
D. J. Barber
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Small Grains

Ba(Mg1/3Ta2/3)O3 thin films were prepared by a sol-gel process involving the reaction of barium isopropoxide, tantalum ethoxide, and magnesium acetate in 2-methoxyethanol and subsequently hydrolysis, spin-coating, and heat treatment. Transmission electron microscopy, x-ray diffraction, and Raman spectroscopy were used for the characterization of the thin films. It was shown that the thin films tend to crystallize with small grains sized below 100 nm. Crystalline phase with cubic (disordered) perovskite structure was formed in the samples annealed at a very low temperature (below 500 °C), and well-crystallized thin films were obtained at 700 °C. Although disordered perovskite is dominant in the thin films annealed below 1000 °C, a low volume fraction of 1 : 2 ordering domains was found in the samples and grows with an increase of annealing temperature.

Sign in / Sign up

Export Citation Format

Share Document