How Fe60Co40 and Fe72Al28 Nano-Alloys Produced by Mechanical Alloying Behave when Exposed to Microwaves

2008 ◽  
Vol 584-586 ◽  
pp. 977-981 ◽  
Author(s):  
Fadhela Otmane ◽  
S. Bergheul ◽  
Z. Hamlati ◽  
M. Azzaz
Keyword(s):  
Solid Solution ◽  
Mechanical Alloying ◽  
Reflection Loss ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
X Band ◽  
Average Grain Size ◽  
Xrd Patterns

Fe60Co40 and Fe72Al28 nano-alloys were synthesized from elemental powders via highenergy mechanical alloying. The prepared samples were characterized using X-ray diffraction, scanning electron microscopy and X-band waveguide to measure the reflection loss in a frequency range of 9-10 GHz. The XRD patterns show that disordered Fe60Co40 solid solution with a bodycentred cubic structure is formed for milling times longer than 12 h, and after 4h milling, the solid solution Fe72Al28 has been largely formed. Morphological studies indicate an average grain size of 10 to 15 nm. The microwave- absorbing characteristic reveal good performance for Fe60Co40 compared to Fe72Al28, the maximum reflection loss is about -12 dB for the absorber.

Structural, dielectric, ferroelectric and impedance spectroscopic studies on Ba1−xSrxTiO3(0.15 ≤ x ≤ 0.35)

2019 ◽  
Vol 33 (17) ◽  
pp. 1950193 ◽  
Author(s):  
Shukdev Pandey ◽  
Om Parkash ◽  
Devendra Kumar
Keyword(s):  
Equivalent Circuit Model ◽  
Solid State Reaction Method ◽  
Spectroscopic Studies ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
X Band ◽  
Xrd Patterns ◽  
Diffuse Phase

Compositions with x = 0.15, 0.20, 0.25, 0.30 and 0.35 were synthesized in the system [Formula: see text] using conventional solid state reaction method and characterized by X-Ray Diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopy (SEM). Tetragonal phase was confirmed in all the samples using Rietveld refinement of the XRD patterns and observation of their Raman spectra. Dielectric and impedance measurements were carried out in the temperature range 300–723 K in the frequency range 1 Hz to 1 MHz. The samples exhibit diffuse phase transition (DPT). Equivalent circuit model involving combination of Constant Phase angle Elements (CPE) and resistances (R) was developed which represents the data well. Expressions for the values of resistances (R) were established in terms of composition and temperature empirically. P-E loops indicated normal ferroelectric behavior for all the samples. Dielectric constant was also measured in the frequency range 8–12 GHz in the X band of microwaves.

Microstructure and Property Evolution of Cu90Zr10 Alloy in the Process of Mechanical Alloying

2013 ◽  
Vol 750-752 ◽  
pp. 667-670
Author(s):  
C.J. Li ◽  
L. Teng ◽  
J. Tan ◽  
Q. Yuan ◽  
J.J. Tang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Alloy Powder ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value ◽  
Average Grain Size ◽  
Energy Ball

Cu90Zr10 alloy powder was prepared by high-energy ball milling. The microstructure and property evolution of this alloy powder during mechanical alloying (MA) were investigated by using X-ray diffraction and optical microscopy (OM). The alloy powder with an average grain size of 10 - 40 nm was obtained, and the grain size was found to decrease gradually with increasing milling time. The microhardness reached a maximum value (about 295 Hv) after 30 h milling. The internal microstrain and the microhardness of the samples increased due to the grain refinement and solid solution during milling, and 10at.% Zr could be brought into Cu lattice by solid solution during MA. At last, the mechanisms of strengthening were discussed.

Elaboration, Structure and Mössbauer Spectroscopy of Nanostructured Fe100−xSix Powders Elaborated by Mechanical Alloying

SPIN ◽  
2017 ◽  
Vol 07 (02) ◽  
pp. 1750002 ◽  
Author(s):  
M. Hemmous ◽  
A. Guittoum
Keyword(s):  
Magnetic Field ◽  
Solid Solution ◽  
Mechanical Alloying ◽  
Hyperfine Magnetic Field ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
The Mean ◽  
Xrd Studies

We have studied the effect of the silicon concentration on the structural and hyperfine properties of nanostructured Fe[Formula: see text]Six powders ([Formula: see text], 20, 25 and 30[Formula: see text]at.%) prepared by mechanical alloying. The X-ray diffraction (XRD) studies indicated that after 72[Formula: see text]h of milling, the solid solution bcc-[Formula: see text]-Fe(Si) is formed. The grain sizes, [Formula: see text]D[Formula: see text] (nm), decreases with increasing Si concentration and reaches a minimum value of 11[Formula: see text]nm. We have found that the lattice parameter decreases with increasing Si concentration. The changes in values are attributed to the substitutional dissolution of Si in Fe matrix. From the adjustment of Mössbauer spectra, we have shown that the mean hyperfine magnetic field, [Formula: see text]H[Formula: see text] (T), decreases with increasing Si concentration. The substitutional dependence of [Formula: see text]H[Formula: see text] (T) can be attributed to the effect of p electrons Si influencing electrons d of Fe.

Influence of Annealing Time on Microstructure of Ni-W Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 613-618
Author(s):  
Qiao Zhang ◽  
Shu Hua Liang ◽  
Chen Zhang ◽  
Jun Tao Zou
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Grain Size ◽  
Grain Boundaries ◽  
Annealing Time ◽  
Single Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Grain Size ◽  
Scanning Electron

The as-cast Ni-W alloys with 15wt%W, 25wt%W and 30wt%W were annealed in hydrogen at 1100. The effect of the annealing time on the microstructure of Ni-W alloys was studied, and the phase constituents and microstructure of annealed Ni-W alloys were characterized by the X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that no any phase changed for Ni-15%W, Ni-25%W and Ni-30%W alloys annealed for 60 min, 90 min and 150 min, which were still consisted of single-phase Ni (W) solid solution. However, microstructure had a significant change after annealing. With increase of annealing time, the microstructure of Ni-15%W alloy became more uniform after annealing for 90 min, and the average grain size was 95μm, whereas the grain size of Ni-15%W alloy increased significantly after annealing for 150 min. For Ni-25%W and Ni-30%W, there was no obvious change on the grain size with increase of annealing time, and the amount of oxides at grain boundaries gradually reduced. After annealing for 150 min, the impurities at grain boundaries almost disappeared. Subsequently, the annealing at 1100 for 150 min was beneficial for the desired microstructure of Ni-25%W and Ni-30%W alloys.

Characterization of BaM and PaNi-Based Radar Absorbency (RAM) Behavior with Multilayer Geometry Structure for X-Band Absorption

2019 ◽  
Vol 966 ◽  
pp. 54-59 ◽  
Author(s):  
Mochamad Zainuri ◽  
Dina Andryani
Keyword(s):  
Reflection Loss ◽  
Soft Magnetic Materials ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Band Frequency ◽  
X Ray ◽  
X Band ◽  
Band Absorption ◽  
Radar Wave

Behavioral characterization of radar absorbent material consisting of Polyaniline (PaNi) and Barium M-Hexaferrite (BaM) has been successfully synthesized by solid state method. Polyaniline conductive material was synthesized using the polymerization method with DBSA dopant. A Radar Absorbing Materials (RAM) is characterized by X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Four Point Probe (FPP), Scanning Electron Microscope (SEM) and Vector Network Analyzer (VNA). The ion Zn 2+ is dopping into the BAM structure, where Zn 2+ ions replace Fe2+ ions in Hexaferrite barium so that the phase becomes soft magnetic materials . RAM and PANi particles are combined with ship paint to form radar wave absorbent coatings. The layer is coated with multilayer geometry on AH 36 type A steel, with thicknesses of 2.4 mm, 3.6 mm, 4.8 mm and 6 mm respectively. The X-band wave absorption was identified by VNA testing, where the maximum reflection loss value was found at 6mm thickness with a reflection loss value - 32.6 dB at 8.4 GHz frequency. Reflection loss values of multilayer variations with a thickness of 2.4 mm, 3.6mm and 4.8mm each have reflection loss values of -8.02 dB, -19.13 dB and -28.9 dB respectively in the x band frequency range.

The synthesis of NbSi2 by mechanical alloying

1997 ◽  
Vol 12 (5) ◽  
pp. 1172-1175 ◽  
Author(s):  
Taiping Lou ◽  
Guojiang Fan ◽  
Bingzhe Ding ◽  
Zhuangqi Hu
Keyword(s):  
Solid Solution ◽  
Differential Scanning Calorimetry ◽  
Intermetallic Compound ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Temperature Rise ◽  
Milling Time ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The stoichiometric intermetallic compound NbSi2 has been synthesized by mechanical alloying (MA) elemental Nb and Si powders. The alloying process has been investigated by means of x-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was found that the formation of the Nb2Si intermetallic compound occurs abruptly after 65 min of milling without any interruptions during the alloying process. However, short interruptions at a 5 min interval during ball milling result in a gradual reaction for the formation of the NbSi2 compound as well as a new metastable bcc structured solid solution. We conclude that the temperature rise during mechanical alloying plays an important role in initiating the abrupt reaction after an incubation milling time.

Synthesis of Nanocrystalline Fe25Al57.5Ni17.5 by Mechanical Alloying

2012 ◽  
Vol 476-478 ◽  
pp. 1318-1321
Author(s):  
Qi Zhi Cao ◽  
Jing Zhang
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Mechanical Alloying ◽  
Ball Mill ◽  
Structural Changes ◽  
Early Stage ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray

Nanostructured Fe25Al57.5Ni17.5intermetallics was prepared directly by mechanical alloying (MA) in a high-energy planetary ball-mill. The phase transformations and structural changes occurring in the studied material during mechanical alloying were investigated by X-ray diffraction (XRD). Thermal behavior of the milled powders was examined by differential thermal analysis (DTA). Disordered Al(Fe,Ni) solid solution was formed at the early stage. After 50 h of milling, Al(Fe,Ni) solid solution transformed into Al3Ni2，AlFe3，AlFe0.23Ni0.77 phase. The power annealed at temperature 500 results in forming of intermetallics AlFe3 and FeNi3 after 5h milling. The nanocrystalline intermetallic compound was obtained after 500h milling.

scholarly journals Electromagnetic characterization of microwave sintered Sr1-xCaxMnO3 (0.0 ≤ x ≤ 0.4) thick films

2013 ◽  
Vol 7 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Rani Pawar ◽  
Ninad Velhal ◽  
Vijaya Puri
Keyword(s):  
Impedance Matching ◽  
Calcium Content ◽  
Frequency Range ◽  
Absorption Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Band ◽  
Electromagnetic Characteristics ◽  
Ku Band

Electromagnetic characteristics of microwave sintered strontium calcium manganites thick film with variation in calcium content have been investigated. The X-ray diffraction analysis reveals tetragonal perovskite structure for all the compositions. The grain size increases with the increase in calcium content. The microwave absorption, complex permittivity, permeability and conductivity are reported in the frequency range of 8.2-18 GHz. The absorption loss is larger in Ku band while insertion loss is larger in X band. The permittivity, permeability and microwave conductivity decreases from X-band to Ku-band. The almost identical values of real part of permittivity and permeability indicate possible application as materials for impedance matching.

Investigation the Structural and Magnetic Properties of FINEMET Type Alloy Produced by Mechanical Alloying

2014 ◽  
Vol 970 ◽  
pp. 252-255 ◽  
Author(s):  
Tayebeh Gheiratmand ◽  
Saeed Mohammadi Siyani ◽  
Hamid Reza Madaah Hosseini ◽  
Parviz Davami
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Mechanical Alloying ◽  
Milled Powder ◽  
Main Peak ◽  
X Ray Diffraction ◽  
Type Alloy ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Transmission Electron

In this research, FINEMET alloy with composition of Fe73.5Si13.5B9Nb3Cu1was produced by mechanical alloying from elemental powders. The effect of milling time on the magnetic and structural properties of alloy has been investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometery. The results showed that milling for 53 hr leads to the formation of Fe supersaturated solid solution which includes Si, B and Nb atoms with mean crystallite size of ~30 nm. The shift of the main peak of Fe to the higher angles indicated that Si and B atoms dissolve in the Fe solid solution, at primary stage of mechanical alloying, up to the 42 hr while Nb atoms dissolve at final stages. The magnetization of milled powder for 53 hr was 173.7 emu/g, almost the same as that of the melt-spun ribbon. In addition; the coercivity reached to 15.5 Oe after 53 hr of milling. The higher value of coercivity in mechanically alloyed samples is attributed to strains induce to the structure during milling and the lack of amorphous phase and exchange interaction between nanograins.

scholarly journals Electroplating Deposition of Bismuth Absorbers for X-ray Superconducting Transition Edge Sensors

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7169
Author(s):  
Jian Chen ◽  
Jinjin Li ◽  
Xiaolong Xu ◽  
Zhenyu Wang ◽  
Siming Guo ◽  
...  
Keyword(s):  
Transition Edge Sensors ◽  
Rhombohedral Structure ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
High Quantum Efficiency ◽  
X Ray ◽  
Transition Edge ◽  
Average Grain Size ◽  
Xrd Patterns ◽  
Electroplating Process

An absorber with a high absorbing efficiency is crucial for X-ray transition edge sensors (TESs) to realize high quantum efficiency and the best energy resolution. Semimetal Bismuth (Bi) has shown greater superiority than gold (Au) as the absorber due to the low specific heat capacity, which is two orders of magnitude smaller. The electroplating process of Bi films is investigated. The Bi grains show a polycrystalline rhombohedral structure, and the X-ray diffraction (XRD) patterns show a typical crystal orientation of (012). The average grain size becomes larger as the electroplating current density and the thickness increase, and the orientation of Bi grains changes as the temperature increases. The residual resistance ratio (RRR) (R300 K/R4.2 K) is 1.37 for the Bi film (862 nm) deposited with 9 mA/cm2 at 40 °C for 2 min. The absorptivity of the 5 μm thick Bi films is 40.3% and 30.7% for 10 keV and 15.6 keV X-ray radiation respectively, which shows that Bi films are a good candidate as the absorber of X-ray TESs.

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