scholarly journals Elaboration and Characterization of the Nanometric Titanium Diboride Powders by Mechanical Milling Method

2020 ◽  
Vol 31 ◽  
pp. 55-58
Author(s):  
I. Stefan ◽  
G. C. Benga
Keyword(s):  
Particle Size ◽  
Titanium Diboride ◽  
Mechanical Milling ◽  
Structural Evolution ◽  
Planetary Mill ◽  
Distribution Analysis ◽  
Wet Milling ◽  
Research Activities ◽  
Titanium Diboride Powders

The research activities are oriented towards elaborating and characterizing nano-sized powders by powder metallurgy technologies based on wet milling in a planetary mill. For the elaboration of the TiB2 powders, a wet milling regime of initial powders was used up to nano size with the following parameters: milling technology by collision, milling times, rotational speed. The characterization of the TiB2 material will include particle size distribution analysis. EDXS and SEM analysis were used to study the structural evolution of the powder after ball milling. The mechanical milling technology, by its milling regimes, proved to be very efficient, obtaining a reduction of the titanium diboride powders particle size up to 50% compared to the initial unmilled powders.

Benefits of Mild Wet Milling of the Intermediates for the Synthesis of Phase-pure Z-type Hexaferrite

2005 ◽  
Vol 20 (8) ◽  
pp. 1939-1942 ◽  
Author(s):  
Jadambaa Temuujin ◽  
Masami Aoyama ◽  
Mamoru Senna ◽  
Taisuke Masuko ◽  
Chie Ando ◽  
...  
Keyword(s):  
Particle Size ◽  
Crystallization Rate ◽  
Planetary Mill ◽  
Favorable Effect ◽  
Dry Milling ◽  
Wet Milling ◽  
Diffusion Distance ◽  
Particle Size Reduction ◽  
Phase Pure ◽  
Basic Layer

A comparative study on the wet and dry milling of the intermediates for the Z-type hexagonal ferrite (Ba3Co2Fe24O41, Z phase) was performed. Phase-pure Z phase was synthesized by wet milling the intermediates comprising M and Y-type hexaferrites. The intermediates were obtained by calcining the stoichiometric powder mixture at 1080 °C. Subsequent wet milling by a planetary mill for 1 h increased the crystallization rate of Z phase upon subsequent heating at 1230 °C. In contrast, dry milling the intermediates resulted in the severe surface amorphization and led to heterogeneous crystalline states. The observed favorable effect of wet milling the intermediates was explained by the particle size reduction for the decrease of diffusion distance while preserving the basic layer units common to the related hexaferrites.

Characterization of 2D MoS2 and WS2 Dispersed in Organic Solvents for Composite Applications

MRS Advances ◽  
2016 ◽  
Vol 1 (32) ◽  
pp. 2303-2308 ◽  
Author(s):  
Alberto Delgado ◽  
Jorge A. Catalan ◽  
Hisato Yamaguchi ◽  
Claudia Narvaez Villarrubia ◽  
Aditya D. Mohite ◽  
...  
Keyword(s):  
Particle Size ◽  
Structural Analysis ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
2D Materials ◽  
Xrd Analysis ◽  
Solution Processing ◽  
Distribution Analysis ◽  
Compositional Uniformity

ABSTRACTIn this work, we have explored the prospects of MoS2 and WS2, both of which are semiconducting 2D materials, for potential composite applications. In order to form 2D materials composites we have to first disperse them chemically in solution. MoS2 and WS2 powders were oversaturated in N-Methyl-2-pyrrolidone (NMP) solution at 37.5 mg/mL and sonicated at room temperature (RT) for sonication times ranging from 30 minutes to close to 24 hours. After solution processing, the samples with the 2D flakes were transferred to an Isopropyl Alcohol (IPA) bath for particle size distribution analysis. We have observed significant changes in particle size distribution spanning two orders of magnitude as a function of the sonication conditions. Specifically, the observed changes in particle size distribution for MoS2 and WS2 powders ranged from 44 microns down to 0.409 microns, and 148 microns down to 0.409, respectively, as compared to the untreated materials. Structural analysis was conducted using the SEM and X-Ray diffraction. The structural analysis using the SEM revealed morphological signatures between the two materials, where the MoS2 flakes had a randomly oriented distribution with occasional triangular flakes. In the case of the WS2, regardless of the sonication conditions, the WS2 flakes seemed to have a characteristic 120° angular distribution at the vertices, representing a rhombus with concave edges. The XRD analysis showed a minute shift in the characteristic peaks that maybe due to strain-induced effects as a result of the solution processing. Optical characterization of the materials was also conducted using Raman Spectroscopy to validate the average layer number resulting from the solution dispersions and the spatial and compositional uniformity of the two material samples.

Effect of Dispersants on Microstructures of Nano Alpha Alumina Developed from Aluminium Dross Waste

2015 ◽  
Vol 1115 ◽  
pp. 378-381 ◽  
Author(s):  
S. Anis Sofia ◽  
Noorasikin Samat ◽  
Meor Yusoff Meor Sulaiman
Keyword(s):  
Particle Size ◽  
Xrd Analysis ◽  
Planetary Mill ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Milling Method ◽  
Aluminium Dross ◽  
Alpha Alumina

This paper compares the effect of dispersants which are Sodium Laureth Sulfate (SLS) and distilled water (DW) on the crystallization, particle size distribution and morphological behavior of nanoalpha Alumina (α-Al2O3) synthesized from Aluminium (Al) dross waste. The synthesizing of nanoα-Al2O3 via wet milling method was performed using a planetary mill for 4 hours at a speed of 550 rpm. The nanoα-Al2O3 powders with dispersants were characterized with x-ray diffraction (XRD), particle size analyzer (PSA) and transmission electron microscopy (TEM). XRD analysis shows the broadening and shifting of peaks after the sample was calcined at 1300 °C, indicating high crystallinity. The crystallite size of α-Al2O3 milled with SLS is also smaller than the α-Al2O3 milled with DW. These results are consistent with the PSA analysis in which the graphs displayed a symmetrical trend. Then, the PSA analysis is validated with TEM observation up to 100000x magnification, particularly for α-Al2O3 milled with SLS.

Effect of Milling Time and Dispersant on Microstructures of Alpha Alumina Nanopowder Synthesized from Aluminium Dross Waste

2011 ◽  
Vol 364 ◽  
pp. 372-376 ◽  
Author(s):  
Yusoff M.S. Meor ◽  
Muslimin Masliana ◽  
Paulus Wilfred ◽  
E. M. Mahdi ◽  
D. Parimala
Keyword(s):  
Particle Size ◽  
Crystallite Size ◽  
Milling Time ◽  
Xrd Analysis ◽  
Planetary Mill ◽  
Wet Milling ◽  
Particle Size Reduction ◽  
Mean Particle Size ◽  
Peak Broadening ◽  
Aluminium Dross

The paper presents a study on the effect of milling time and addition of SLS dispersant on the crystallite and particle size reduction of α-alumina produced from aluminium dross waste. Wet milling was performed in high velocity planetary mill at speed of 1100 rpm and milled for 2 to 5 hours. XRD analysis shows both peak broadening and shifting occurred especially at longer milling time. The peak broadening effect was then used to calculate both the crystallite size and lattice strain. Samples milled with dispersant gave smaller crystallite size and the smallest crystallite value was 39.4nm obtained using 5 hours milling time. Similarly the mean particle size obtained for samples milled with dispersant gave smaller value and the smaller mean particle size obtained was 0.771 μm after 5 hours of milling.

Incorporation of micro/nanoparticles of PCL with essential oil of Cymbopogon nardus in bacterial cellulose

2018 ◽  
Vol 1 (2) ◽  
pp. 37
Author(s):  
Aline Krindges ◽  
Vanusca Dalosto Jahno ◽  
Fernando Morisso
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Essential Oil ◽  
Zeta Potential ◽  
Bacterial Cellulose ◽  
Culture Medium ◽  
Static Culture ◽  
Cymbopogon Nardus ◽  
Cellulose Membranes

Incorporation studies of particles in different substrates with herbal assets growing. The objective of this work was the preparation and characterization of micro/nanoparticles containing cymbopogon nardus essential oil; and the incorporation of them on bacterial cellulose. For the development of the membranes was used the static culture medium and for the preparation of micro/nanoparticles was used the nanoprecipitation methodology. The incorporation of micro/nanoparticles was performed on samples of bacterial cellulose in wet and dry form. For the characterization of micro/nanoparticles were carried out analysis of SEM, zeta potential and particle size. For the verification of the incorporation of particulate matter in cellulose, analyses were conducted of SEM and FTIR. The results showed that it is possible the production and incorporation of micro/nanoparticles containing essential oil in bacterial cellulose membranes in wet form with ethanol.

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

scholarly journals Average fractional polarization of extragalactic sources at Planck frequencies

2018 ◽  
Vol 618 ◽  
pp. A29 ◽  
Author(s):  
T. Trombetti ◽  
C. Burigana ◽  
G. De Zotti ◽  
V. Galluzzi ◽  
M. Massardi
Keyword(s):  
High Sensitivity ◽  
Point Sources ◽  
Distribution Analysis ◽  
Microwave Background ◽  
Residual Noise ◽  
Upper Limits ◽  
Dusty Galaxies ◽  
Using Data ◽  
Polarization Fraction

Recent detailed simulations have shown that an insufficiently accurate characterization of the contamination of unresolved polarized extragalactic sources can seriously bias measurements of the primordial cosmic microwave background (CMB) power spectrum if the tensor-to-scalar ratio r ∼ 0.001, as predicted by models currently of special interest (e.g., Starobinsky’s R2 and Higgs inflation). This has motivated a reanalysis of the median polarization fraction of extragalactic sources (radio-loud AGNs and dusty galaxies) using data from the Planck polarization maps. Our approach, exploiting the intensity distribution analysis, mitigates or overcomes the most delicate aspects of earlier analyses based on stacking techniques. By means of simulations, we have shown that the residual noise bias on the median polarization fraction, Πmedian, of extragalactic sources is generally ≲0.1%. For radio sources, we have found Πmedian ≃ 2.83%, with no significant dependence on either frequency or flux density, in good agreement with the earlier estimate and with high-sensitivity measurements in the frequency range 5–40 GHz. No polarization signal is detected in the case of dusty galaxies, implying 90% confidence upper limits of Πdusty ≲ 2.2% at 353 GHz and of ≲3.9% at 217 GHz. The contamination of CMB polarization maps by unresolved point sources is discussed.

scholarly journals Characterization of Steel Slag Filler and Its Effect on Aging Resistance of Asphalt Mastic with Various Aging Methods

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 869
Author(s):  
Minghua Wei ◽  
Shaopeng Wu ◽  
Haiqin Xu ◽  
Hechuan Li ◽  
Chao Yang
Keyword(s):  
Particle Size ◽  
Surface Characterization ◽  
Steel Slag ◽  
Self Healing ◽  
Limestone Filler ◽  
Asphalt Mastic ◽  
Pore Characterization ◽  
Asphalt Mastics ◽  
Healing Property

Steel slag is the by-product of the steelmaking industry, the negative influences of which prompt more investigation into the recycling methods of steel slag. The purpose of this study is to characterize steel slag filler and study its feasibility of replacing limestone filler in asphalt concrete by evaluating the resistance of asphalt mastic under various aging methods. Firstly, steel slag filler, limestone filler, virgin asphalt, steel slag filler asphalt mastic and limestone filler asphalt mastic were prepared. Subsequently, particle size distribution, surface characterization and pore characterization of the fillers were evaluated. Finally, rheological property, self-healing property and chemical functional groups of the asphalt mastics with various aging methods were tested via dynamic shear rheometer and Fourier transform infrared spectrometer. The results show that there are similar particle size distributions, however, different surface characterization and pore characterization in the fillers. The analysis to asphalt mastics demonstrates how the addition of steel slag filler contributes to the resistance of asphalt mastic under the environment of acid and alkaline but is harmful under UV radiation especially. In addition, the pore structure in steel slag filler should be a potential explanation for the changing resistance of the asphalt mastics. In conclusion, steel slag filler is suggested to replace limestone filler under the environment of acid and alkaline, and environmental factor should be taken into consideration when steel slag filler is applied to replace natural fillers in asphalt mastic.

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