scholarly journals Effects of Recycled Fe2O3 Nanofiller on the Structural, Thermal, Mechanical, Dielectric, and Magnetic Properties of PTFE Matrix

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2332
Author(s):  
Ahmad Mamoun Khamis ◽  
Zulkifly Abbas ◽  
Raba’ah Syahidah Azis ◽  
Ebenezer Ekow Mensah ◽  
Ibrahim Abubakar Alhaji

The purpose of this study was to improve the dielectric, magnetic, and thermal properties of polytetrafluoroethylene (PTFE) composites using recycled Fe2O3 (rFe2O3) nanofiller. Hematite (Fe2O3) was recycled from mill scale waste and the particle size was reduced to 11.3 nm after 6 h of high-energy ball milling. Different compositions (5–25 wt %) of rFe2O3 nanoparticles were incorporated as a filler in the PTFE matrix through a hydraulic pressing and sintering method in order to fabricate rFe2O3–PTFE nanocomposites. The microstructure properties of rFe2O3 nanoparticles and the nanocomposites were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). The thermal expansion coefficients (CTEs) of the PTFE matrix and nanocomposites were determined using a dilatometer apparatus. The complex permittivity and permeability were measured using rectangular waveguide connected to vector network analyzer (VNA) in the frequency range 8.2–12.4 GHz. The CTE of PTFE matrix decreased from 65.28×10−6/°C to 39.84×10−6/°C when the filler loading increased to 25 wt %. The real (ε′) and imaginary (ε″) parts of permittivity increased with the rFe2O3 loading and reached maximum values of 3.1 and 0.23 at 8 GHz when the filler loading was increased from 5 to 25 wt %. A maximum complex permeability of 1.1−j0.07 was also achieved by 25 wt % nanocomposite at 10 GHz.

2012 ◽  
Vol 730-732 ◽  
pp. 739-744 ◽  
Author(s):  
Petr Urban ◽  
Francisco Gomez Cuevas ◽  
Juan M. Montes ◽  
Jesus Cintas

The amorphization process by mechanical alloying in the Fe-Si alloy system has been studied. High energy ball milling has been applied for alloys synthesis. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to monitor the structural and phase transformations through the different stages of milling. The addition of amorphous boron in the milling process and the increase of the milling time were used to improve the formation of the amorphous phase. Heating the samples resulted in the crystallization of the synthesized amorphous alloys and the appearance of equilibrium intermetallic compounds.


1994 ◽  
Vol 9 (2) ◽  
pp. 297-304 ◽  
Author(s):  
J.S. Luo ◽  
H.G. Lee ◽  
S.N. Sinha

The microstructure and superconducting properties of Bi2Sr2CaCu2Ox (Bi-2212) during high-energy attrition milling were investigated in detail by a combination of x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and magnetization techniques. The starting superconducting powder was milled in a standard laboratory attritor using yttria-stabilized ZrO2 balls and a stainless steel tank. After selected time increments, the milling was interrupted and a small quantity of milled powder was removed for further analysis. It was found that the deformation process rapidly refines Bi-2212 into nanometer-size crystallites, increases atomic-level strains, and changes the plate-like morphology of Bi-2212 to granular submicron clusters. At short milling times, the deformation seems localized at weakly linked Bi-O double layers, leading to twist/cleavage fractures along the {001} planes. The Bi-2212 phase decomposes into several bismuth-based oxides and an amorphous phase after excessive deformation. The superconducting transition is depressed by about 10 K in the early stages of milling and completely vanishes upon prolonged deformation. A deformation mechanism is proposed and correlated with the evolution of superconducting properties. The practical implications of these results are presented and discussed.


1988 ◽  
Vol 132 ◽  
Author(s):  
E. Hellstern ◽  
H. J. Fecht ◽  
C. Garland ◽  
W. L. Johnson ◽  
W. M. Keck

ABSTRACTWe investigated through X- ray diffraction and transmission electron microscopy the crystal refinement of the intermetallic compound AIRu by high- energy ball milling. The deformation process causes a decrease of crystal size to 5–7 rum and an increase of atomic level strain. This deformation is localized in shear bands with a thickness of 0.5 to 1 micron. Within these bands the crystal lattice breaks into small grains with a typical size of 8–14 rum. Further deformation leads to a final nanocrystalline structure with randomly oriented crystallite grains separated by high- angle grain boundaries.


1993 ◽  
Vol 8 (2) ◽  
pp. 307-313 ◽  
Author(s):  
K. Aoki ◽  
A. Memezawa ◽  
T. Masumoto

An intermetallic compound c–NiZr and a mixture of elemental powders of nickel and zirconium [Ni50Zr50 (at. %)] have been mechanically ground (MG) and mechanically alloyed (MA), respectively, using a high-energy ball mill in various atmospheres. The products were characterized by x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and chemical analysis as a function of milling time. An amorphous a–NiZr alloy was prepared by both MG and MA in an argon atmosphere. By MG of NiZr, an amorphous nitride a–NiZrN0.15 was synthesized in a nitrogen atmosphere, while a crystalline hydride c–NiZrH3 was formed in a hydrogen atmosphere. On the other hand, ZrN and ZrH2 were formed by MA in a nitrogen and a hydrogen atmosphere, respectively. The amorphization reaction was observed between ZrH2 and Ni by further MA in a hydrogen atmosphere, and a mixture of a–NiZrxHy (x < 1) and ZrH2 was obtained. However, no amorphization was observed by MA between ZrN and Ni in a nitrogen atmosphere. The effects of the milling atmosphere on the phase formations during MG and MA are discussed based on the gas absorption rate.


1980 ◽  
Vol 1 ◽  
Author(s):  
J. T. Schott ◽  
J. J. Comer

ABSTRACTVarious characterization techniques are applied to pulsed and cw laser-annealed polysilicon layers deposited on oxide layers. The results are used to compare these techniques as to the type and completeness of information provided, as well as sample preparation requirements and general ease or difficulty of measurement. The techniques employed include scanning electron microscopy (SEM), electron channeling micrographs and selected area channeling patterns (SACP), reflection (high energy) electron diffraction (RHEED), transmission electron microscopy (TEM) and selected area diffraction (SAD), x-ray diffraction, optical techniques and etching techniques.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mutaz Salih ◽  
M. Khairy ◽  
Babiker Abdulkhair ◽  
M. G. Ghoniem ◽  
Nagwa Ibrahim ◽  
...  

Abstract In this paper, Sn-doped TiO2 nanomaterials with varying concentrations were manufactured through a simple procedure. The fabricated TiO2 and Sn loaded on TiO2 nanoparticles were studied using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-rays, Fourier transform infrared spectroscopy, and resistance analyses. The benefits of dielectric constant and ac conductivity rise at high Sn loaded concentration on TiO2 nanoparticles. The enhanced electrical conductivity is seen for STO3 (3.5% Sn doped TiO2) and STO4 (5% Sn doped TiO2) specimens are apparently associated with the introduced high defect TiO2 lattice. Furthermore, the fabricated specimens’ obtained findings may be applied as possible candidates for high-energy storage devices. Moreover, proper for the manufacture of materials working at a higher frequency.


2005 ◽  
Vol 498-499 ◽  
pp. 331-336 ◽  
Author(s):  
R. Muccillo ◽  
L. Franchi ◽  
J.T. Santos ◽  
I.C. Cosentino ◽  
E.N.S. Muccillo

Strontium ferrites powders were obtained by high energy milling process after calcinations of iron oxide and barium carbonate. Phase formations and crystallite size was determined using X-ray diffraction. Morphology, particle size and agglomeration stages were analyzed using scanning and transmission electron microscopy. Results show particles in the range of 14 to 40 nanometers, large agglomerates and crystalline phases formation.


2018 ◽  
Vol 54 ◽  
pp. 136-145
Author(s):  
A. El Mohri ◽  
M. Zergoug ◽  
K. Taibi ◽  
M. Azzaz

Nanocrystalline Fe90Mg10 alloy samples were prepared by mechanical alloying process using planetary high energy ball mill. The prepared powders were characterized using differential thermal analysis (DTA), X-ray diffraction technique (XRD) at high temperature, transmission electron microscopy (TEM), and the vibrating sample magnetometer (VSM). Obtained results are discussed according to milling time. XRD at high temperature results also indicated that when the milling time increases, the lattice parameter and the mean level of grain size increase, whereas the microstrains decrease. The result of the observation by the TEM of the Fe-Mg powders prepared in different milling time, coercive fields derived and Saturation magnetization derived from the hysteresis curves in high temperature are discussed as a function of milling time.


2007 ◽  
Vol 353-358 ◽  
pp. 1505-1508
Author(s):  
Zhi Hua Yang ◽  
Yu Zhou ◽  
De Chang Jia ◽  
Qing Chang Meng ◽  
Chang Qing Yu

Amorphous Si-B-C-N ceramics obtained by high energy ball milling and hot pressing using hexagonal boron nitride (h-BN), graphite (C) and amorphous Si as starting materials have been studied. The mechanical milling with high energy resulted in the generation of large amounts of amorphous composites only milled for 5 h. Si-B-C-N powders were consolidation by hot pressing at 1850 °C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) show that small amount of BN and SiC crystal lies in the amorphous matrix. The flexural strength reached the maximal value of 137.2 MPa at a mole ratio of BN/(Si+C) being 0.6.


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