scholarly journals An overstoichiometric Nd-Fe-B hard magnetic material

2010 ◽  
Vol 75 (9) ◽  
pp. 1271-1277 ◽  
Author(s):  
Tomás Zák ◽  
Nadezda Talijan ◽  
Vladan Cosovic ◽  
Jasna Stajic-Trosic ◽  
Aleksandar Grujic
Keyword(s):  
Magnetic Material ◽  
Thermal Treatment ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Hard Magnetic Material ◽  
State Measurement ◽  
Before And After ◽  
Rich Alloy ◽  
Thermomagnetic Curve ◽  
Quality Material

A commercial Nd-rich Nd-Fe-B-based hard magnetic material was studied. The obtained results were compared before and after recording of the thermomagnetic curve up to 800?C. The curve itself showed clearly besides Curie points of the Nd2Fe14B phase and ?-Fe also another critical temperature. M?ssbauer spectroscopic (MS) phase analysis and X-Ray diffraction analysis (XRD) showed in addition to the commonly known phases Nd2Fe14B and NdFe4B4 also some paramagnetic and ferromagnetic iron atoms (MS) and Fe17Nd2 intermetallics (XRD). During the exerted thermal treatment, the content of the Nd2Fe14B and NdFe4B4 phases remained almost unchanged, while iron atoms from remnant minor phases built a separate ?-Fe phase. The XRD pattern also showed the presence of some minor Nd phase. The results of SQUID magnetic measurements suggest a nanocrystalline decoupled structure of the Nd-rich alloy in the optimized magnetic state. Measurement of the magnetization loop showed, in spite of small changes in the phase composition, that magnetic properties of the quality material deteriorated during the thermal treatment.

XRD investigation of thermal degradation of some gamma-irradiated polyethylene terephthalate samples

2019 ◽  
Vol 33 (12) ◽  
pp. 1950111 ◽  
Author(s):  
Mihai Todica ◽  
Zoltan Kovacs-Krauss ◽  
Carmen Niculaescu ◽  
Marieta Mureşan-Pop
Keyword(s):  
Thermal Treatment ◽  
Polyethylene Terephthalate ◽  
Structural Changes ◽  
Diffraction Method ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Gamma Irradiated ◽  
Different Doses

The modification of local structure of some commercial polyethylene terephthalate (PET) samples, gamma irradiated at different doses, was investigated by X-ray diffraction method before and after thermal treatment. Before the thermal treatment, the samples exposed to different doses of gamma radiations, does not show noticeable structural changes. However, the gamma exposure affects the thermal behavior of samples submitted to melting–cooling process. These modifications have been highlighted by X-ray diffraction, and confirmed also by thermal analysis and electron spin resonance spectroscopy.

Characterization of silica polymorphs in kaolins by X-ray diffraction before and after phosphoric acid digestion and thermal treatment

2005 ◽  
Vol 552 (1-2) ◽  
pp. 201-206 ◽  
Author(s):  
Sibel Kahraman ◽  
Müşerref Önal ◽  
Yüksel Sarıkaya ◽  
İhsan Bozdoğan
Keyword(s):  
Thermal Treatment ◽  
Phosphoric Acid ◽  
Acid Digestion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After

Effect of Thermal Treatment on the Physical Properties of Electrospun PVDF Membrane

2012 ◽  
Vol 591-593 ◽  
pp. 1113-1116
Author(s):  
Si Chen Cheng ◽  
Yin Zheng Liang ◽  
Yi Ping Qiu
Keyword(s):  
Thermal Treatment ◽  
Tensile Property ◽  
Tensile Testing ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Pvdf Membrane ◽  
X Ray ◽  
Before And After ◽  
Poly Vinylidene Fluoride

The electrospinning technique was used to produce poly (vinylidene fluoride) (PVDF) membrane. Thermal treatment was introduced to improve the mechanical property and dimensional stability. In this paper, the PVDF membranes before and after thermal treatment were characterized by Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD), tensile testing. The crystallinity, tensile property, as well as melting temperature changed with the treated temperature. The results hows that thermal treatment could notably increase the tensile property of electrospun PVDF membrane and 160°C is a proper temperature for thermal treating

scholarly journals Influence Of Thermal Treatment On Relaxor Properties Of BaBi2Nb2O9 Ceramics

2015 ◽  
Vol 60 (2) ◽  
pp. 545-550 ◽  
Author(s):  
M. Adamczyk ◽  
M. Pilch ◽  
M. Pawełczyk
Keyword(s):  
Thermal Treatment ◽  
High Vacuum ◽  
Temperature Characteristic ◽  
Unit Cell ◽  
Xps Analysis ◽  
X Ray Diffraction ◽  
Depolarization Current ◽  
Cell Parameters ◽  
Before And After ◽  
Modified Surface

Abstract In the hereby paper the implications of thermal modification of BaBi2Nb2O9 ceramics in high vacuum (5×10−11 bar) at a temperature equal of 1173K are widely discussed. The mentioned modification caused changes in the ions concentration (confirmed by EDS and XPS analysis) and as a consequence an influence on the value of the unit cell parameters as well as on the dielectric and relaxor properties of described ceramics. The obtained results of EDS and XPS analysis of the sample before and after thermal treatment revealed bismuth ions diffusion to the surface of the sample (which was expected) and an almost complete the lack of barium ions on the modified surface. The comparison of EDS and XPS analysis results, suggested that they penetrated the interior of the sample and embedded into the crystal structure in place of bismuth. The hypothesis is in good agreement with the results of X-ray diffraction – the volume of the unit cell had an insignificant increase. The changes in the ions concentration influenced, also in a distinct manner, the dielectric and relaxor properties as well as on the shape of temperature characteristic of thermal stimulated depolarization current observed in BBN ceramics.

scholarly journals Study of the influence of autoclave sterilization on the properties of citrate functionalized iron oxide nanoparticles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Thomas Girardet ◽  
Amel Cherraj ◽  
Astrid Pinzano ◽  
Christel Henrionnet ◽  
Franck Cleymand ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Magnetic Measurements ◽  
Superparamagnetic Iron Oxide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Water Dispersible ◽  
Before And After ◽  
One Step

Abstract Superparamagnetic Iron Oxide Nanoparticles (SPIONs) are widely used in various areas of the biomedical field: for diagnosis (Magnetic Resonance Imaging), for therapeutic applications (hyperthermia, nanovectorization). These applications require a good stability in water and no aggregation of SPIONs, with well-controlled physicochemical and magnetic properties. In this work, SPIONs functionalized by citrate ligands are synthesized in a one-step process with the aim of producing stable water-dispersible nanoparticles with a well-crystallized spinel structure. Microwave technology is implemented to achieve this objective given the ease, speed and reproducibility of the method. For their future use in biomedical applications, the sterilization of these SPIONs are essential by an autoclave treatment. The influence of this treatment on the physicochemical and magnetic properties of the SPIONs is determined by a systematic characterization before and after sterilization by Transmission Electronic Microscopy, Dynamic Light Scattering, X-ray Diffraction, Fourier Transformed Infra-Red, ThermoGravimetric Analysis and magnetic measurements.

Studies on Al2O3 - ZrO2 Coatings Structure before and after Thermal Treatment

2007 ◽  
Vol 130 ◽  
pp. 297-301 ◽  
Author(s):  
Ludwik Górski ◽  
Andrzej Pawłowski
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Treatment ◽  
Tetragonal Zirconia ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ordered Phases ◽  
Before And After ◽  
Fine Crystalline Structure

Phase transitions occurring in the Al2O3-ZrO2 composite as a result of plasma spraying and subsequent coating annealing are described. X-ray diffraction and transmission electron microscopy methods are applied to study these effects. Separate layers of amorphous, nano- and fine-crystalline structure with the columnar crystals areas have been observed. Thermal treatment causes formation of more ordered phases. Effect of partial stabilization of cubic and tetragonal zirconia due to the presence of alumina has been remarked.

INFLUENCE OF THE PREPARATION CONDITIONS AND THERMAL TREATMENT ON THE STRUCTURE OF THE B2O3-BaO-Fe2O3 SYSTEM

2005 ◽  
Vol 19 (10) ◽  
pp. 1821-1834 ◽  
Author(s):  
DORINA RUSU ◽  
M. F. CARRASCO ◽  
MONICA TODERAS ◽  
I. ARDELEAN
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Thermal Treatment ◽  
Optical Microscopy ◽  
Magnetic Measurements ◽  
Iron Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Preparation Conditions ◽  
Cooling Method

The structure of x Fe 2 O 3·(100-x)[3 B 2 O 3· BaO ] system with 0≤x≤50 mol % was studied by DTA, X-ray diffraction, density, optical microscopy and EPR measurements in vitreous and partial crystallized state, the samples being obtained by under cooling method. The data obtained show that, by melting the samples at Te = 1200°C or Te = 1250° C , glasses for x≤35 mol % were obtained, and the forming of crystalline microprecipitates of Fe 2 O 3 in the sample with x = 50 mol %. It was also established that the thermal treatment at 565°C without and in the presence of magnetic field of 0.7 T is influencing the forming and the development of the Fe 2 O 3 microcrystals in samples with x≥35 mol %. The samples melted at Tc = 1200° C and Tc = 1250° C were studied by magnetic susceptibility measurements which evidenced similar results with those obtained by EPR. Also, the magnetic measurements show that for the thermal untreated samples the iron ions participate at superexchange interactions for x≥5 mol % and for x≥10 mol %, respectively.

scholarly journals Thermal treatment of magnetite nanoparticles

2015 ◽  
Vol 6 ◽  
pp. 1385-1396 ◽  
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.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Effect of MWCNT doping on the structural and optical properties of PVC/PVDF polymer blend

2017 ◽  
Vol 13 (2) ◽  
pp. 4640-4647
Author(s):  
A. M. Abdelghany ◽  
M.S. Meikhail ◽  
S.I. Badr ◽  
A. S. Momen
Keyword(s):  
Surface Damage ◽  
X Ray Diffraction ◽  
Dopant Content ◽  
Casting Technique ◽  
Transmission Electron ◽  
Dopant Level ◽  
Before And After ◽  
Carbon Nano Tubes ◽  
Small Band ◽  
Vibrational Bands

Thin film samples of pristine polyvinyl chloride (PVC), poly vinyldine fluoride (PVDF) in combination with their blend in addition to samples containing factorial mass fraction of multi wall carbon nano-tubes (MWCNTs) in the dopant level were prepared via routine casting technique using tetrahydrofurane (THF) as a common solvent. X-ray diffraction and transmission electron microscopy (TEM) depict the nano-scale (15-25 nm) of functionalized MWCNTs with no surface damage results from functionalization process.X-ray diffraction (XRD) shows a semi-crystalline nature of PVDF with evidence for more than one phase namely a and b phases. The fraction of b phase was calculated and correlated to the dopant content. FTIR optical absorption spectra revels a preservation of the main vibrational bands before and after addition of MWCNTs in the doping level with a presence of new small band 1151 cm-1 assigned for the interaction and complexation between constituents.

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