Hydrogen Absorpsivity-Desorbsivity of Mg Doped by Ni, Cu, Al Produced by Mechanical Alloying

2013 ◽  
Vol 789 ◽  
pp. 37-41
Author(s):  
Widyastuti ◽  
Budi P. Febrian ◽  
Sutarsis
Keyword(s):  
Particle Size ◽  
Hydrogen Storage ◽  
Mechanical Alloying ◽  
Milling Time ◽  
Weight Percent ◽  
Manufacturing Method ◽  
Highest Weight ◽  
Hydrogenation Temperature ◽  
Element Addition ◽  
Mg Doped

Mg, in the form of MgH2,is one kinds of materials widely used as hydrogen storage materials. Absorption and desorption properties of hydrogen which comes from metal hydride depend on materials itself, addition of elements, as well as manufacturing method. In this research, Mg as hydrogen storage were prepared by mechanical alloying with Ni, Cu, and Al as element addition and variation milling time for 10, 20 and 30 hours. Some morphological analyses (XRD, SEM) were done to observe phase transformation. Absorption and desorption properties characterization were employed by DSC and hydrogenation tests. The improvement in milling time decreased particle size, therefore enhanced wt% of absorbed hydrogen and decrease onset desorption temperature. However, the excessive of agglomeration and cold welding on mechanical alloying process resulted in bigger particle size. Alloying elements, Al and Cu, served as catalyst, while Ni acted as alloying which reacted with hydrogen. Mg10wt%Al with 20 hours milling time at hydrogenation temperature 250°C, 3 atm pressure, and 1 hour holding time resulted in the highest weight percent of H2(0.38%wt). However, Mg10wt%Al with 30 hours milling time had the lowest onset temperature, 341.49°C

Synthesis of the Mümetal Magnetic Powders by Mechanical Alloying

2011 ◽  
Vol 672 ◽  
pp. 157-160
Author(s):  
Ionel Chicinaş ◽  
Viorel Pop ◽  
Florin Popa ◽  
Virgiliu Călin Prică ◽  
Traian Florin Marinca ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Mechanical Alloying ◽  
Size Distribution ◽  
Milling Time ◽  
Cast Alloy ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapid Formation

The formation of quaternary 76Ni17Fe5Cu2Cr (wt. %) alloy by mechanical alloying is investigated. The elemental powders of Ni, Fe, Cu and Cr where milled in argon atmosphere in a planetary ball mill for time up to 20 h. Formation of the alloy was checked by X-ray diffraction studies. It is found that the rapid formation of the alloy lead to the rapid establishment of an equilibrium between the welding and fracture process during milling, leading to a constant particle size distribution over a big range of milling time. The morphology of the powders, studied by scanning electron microscopy (SEM) confirms the rapid increase in size. The particle size distribution and the flowability of the powders are also analyzed as a function of milling time. Enhanced magnetization was found for the milled samples, compared to a cast alloy.

Different Cr Contents in Nanostructured Fe-Ni-Cr Alloys Prepared by Mechanical Alloying

2012 ◽  
Vol 531-532 ◽  
pp. 437-441 ◽  
Author(s):  
Qi He ◽  
Tao Liu ◽  
Jian Liang Xie
Keyword(s):  
Particle Size ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Lattice Distortion ◽  
Milling Time ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ball Milling Time ◽  
Scanning Electron

Fe-Ni-Cr alloy powders with the different components were prepared by Mechanical Alloying (MA). The phase structure, grain size, micro-strain and lattice distortion were determined with X-ray diffraction. The morphology and particle size of the powders were observed and analyzed using a field emission scanning electron microscopy. The results showed that the Fe-Ni-Cr nanocrystalline powders could be obtained by MA. The ball milling time could be reduced with increasing amount of Cr, resulting the formation of Fe-Ni-Cr powders. With the increasing amount of Cr, the speed of Ni diffusion to Fe lattice approaching saturation became more rapid. The particle size got smaller as the ball milling went further; the extent of micro-strain and distortion of lattice intensified; the solid solubility of Ni and Cr in Fe was increased. Finally the super-saturated solid solution of Fe was obtained.

scholarly journals The effect of milling time on the alumina phase transformation in the AMCs powder metallurgy reinforced by silica-sand-tailings

2022 ◽  
pp. 103-117
Author(s):  
Sukanto ◽  
Wahyono Suprapto ◽  
Rudy Soenoko ◽  
Yudy Surya Irawan
Keyword(s):  
Particle Size ◽  
Phase Transformation ◽  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Milling Time ◽  
Sintering Temperature ◽  
Silica Sand ◽  
Second Phase ◽  
The Matrix ◽  
The Impact

This study aims to determine the effect of milling time and sintering temperature parameters on the alumina transformation phase in the manufacture of Aluminium Matrix Composites (AMCs) reinforced by 20 % silica sand tailings using powder metallurgy technology. The matrix and fillers use waste to make the composites more efficient, clean the environment, and increase waste utilization. The milling time applied to the Mechanical Alloying (MA) process was 0.5, 6, 24, 48, and 96 hours, with a ball parameter ratio of 15:1 and a rotation of 93 rpm. Furthermore, hot compaction was carried out using a 100 MPa two-way hydraulic compression machine at a temperature of 300 °C for 20 minutes. The temperature variables of the sintering parameter process were 550, 600 to 650 °C, with a holding time of 10 minutes. Characterization of materials carried out included testing particle size, porosity, X-Ray Diffraction (XRD), SEM-Image, and SEM-EDX. The particle measurement of mechanical alloying processed, using Particle Size Analyzer (PSA) instrument and based on XRD data using the Scherrer equation, showed a relatively similar trend, decreasing particle size occurs when milling time was increased 0.5 to 24 hours. However, when the milling time increases to 48 and 96 hours, the particle size tends to increase slightly, due to cold-weld and agglomeration when the Mechanical Alloying is processed. The impact is the occurrence of the matrix and filler particle pairs in the cold-weld state. So, the results of XRD and SEM-EDX characterization showed a second phase transformation to form alumina compounds at a relatively low sintering temperature of 600 °C after the mechanical alloying process was carried out with a milling time on least 24 hours

Solid State Amorphization of Ti60Si40 Alloy via Mechanical Alloying

2021 ◽  
Vol 876 ◽  
pp. 7-12
Author(s):  
Petr Urban ◽  
Fátima Ternero Fernández ◽  
Rosa M. Aranda Louvier ◽  
Raquel Astacio López ◽  
Jesus Cintas Físico
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Mechanical Alloying ◽  
Amorphous Phase ◽  
Milling Time ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Heating Up

The effect of milling time on the microstructure evolution and formation of amorphous phase of Ti60Si40 alloy produced by mechanical alloying (MA) has been investigated. Laser diffraction, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) were employed to characterize the particle size, morphology and structure of mechanically alloyed Ti60Si40. When the milling time is increased to 20 h, the particle size decreases from 23.7 to 4.7 μm, the shape of the particles changes to spherical and the crystalline structure is transformed into an amorphous phase. The amorphous Ti60Si40 alloy is stable when heating up to 750oC. Above this temperature, the cold crystallization of the intermetallic compounds Ti5Si3 and/or Ti5Si4 begins.

Microstructural Studies of (Ba0.7Sr0.3Fe12O19)1-x - (Ba0.7Sr0.3TiO3)x with x = 0.2, x = 0.5 and x = 0.8 Composite System by Mechanical Alloying Process

2014 ◽  
Vol 896 ◽  
pp. 391-395
Author(s):  
Novizal ◽  
Azwar Manaf ◽  
P. Sardjono
Keyword(s):  
Particle Size ◽  
Composite Materials ◽  
Mechanical Alloying ◽  
Crystallite Size ◽  
Composite System ◽  
Milling Time ◽  
X Ray ◽  
Mean Particle Size ◽  
The Mean ◽  
Composite Samples

In this paper, we report our investigation on material structure analysis of (Ba0.7Sr0.3Fe12O19)1-x-(Ba0.7Sr0.3TiO3)x with x = 0.2, x = 0.5 and x = 0.8 composite system prepared by a mechanical alloying process to promote feroic properties. It is shown that the x-ray diffraction patterns of each composition for the composite materials are the same. It consisted of the mixture for the two phases. The average of particle size for each respective phase in the composite materials was found initially increased, up to 18-20 μm after mechanically milled for 40 hours, then start to decreased to a smaller size ~ 8-10 μm after 80 hrs milling time. However, a plot of particle size against the milling time for each composite phase shown a trend of further reduction in the mean particle sizes. In addition, the x-ray traces of dense pellet samples after sintering the milled powders at a temperature of 1100 °C showed broadened diffracted peaks pattern due to fine crystallites in the samples. Results of mean crystallite size determination of respective phases in the composite samples showed the same trend, a decrease with milling time toward values about 10 nm at 80 hrs milling time. Hence, sintering to the milled particles has promoted the formation of nanocrystal containing particles. When compared between the mean particle size and mean crystallite size of respective phase in the composite samples, the mean crystallite size for magnetic phase (B7S3F) was found more than 100 times smaller than the mean particle size of composite particles. However, finer mean crystallite sizes were found in the ferroelectric phase (B7S3T) in which the mean was about 200 times smaller than the mean particle size.

Research of the Milling Time Influence on Ag-Cu Powder Particles Size Processed by Mechanical Alloying Route

2012 ◽  
Vol 188 ◽  
pp. 382-387 ◽  
Author(s):  
Oana Gîngu ◽  
Claudiu Nicolicescu ◽  
Gabriela Sima
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Mechanical Alloying ◽  
Size Distribution ◽  
Powder Mixture ◽  
Milling Time ◽  
High Energy ◽  
Milling Process ◽  
Future Research ◽  
Powder Particles

This research focuses on Ag-Cu powder particles processing by mechanical alloying (MA) route. The powder mixture is representative for the eutectic composition, respectively 72%wt. Ag + 28% wt. Cu. The milling process is developed in high energy ball mill Pulverisette 6, using different size for the milling balls, in wet conditions for 80 hours. One of the most important parameter studied in this research is the particle size distribution of the processed powder mixture. Thus, it changes along the milling time, from 10…75 µm at the beginning of MA process up to (60 – 80) nm at 80 h. The milling parameters will be optimized in future research depending on the particle size distribution related with thermophysical and thermodynamic properties focused on electrical and optical properties improvement.

scholarly journals Pengaruh Katalis Fe2O3 Pada Tabung Penyimpanan Hidrogen Berbasis MgH2 Melalui Teknik Mechanical Alloying

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Andia Fatmaliana ◽  
Maulinda Maulinda ◽  
Nirmala Sari
Keyword(s):  
Hydrogen Storage ◽  
Mechanical Alloying ◽  
Alternative Energy ◽  
Milling Time ◽  
Electrical Energy ◽  
Precipitation Method ◽  
Release Time ◽  
Hydrogen Storage Materials ◽  
Strong Bond ◽  
Hematite Fe2o3

<p>Hydrogen is an alternative energy that has a very abundant amount in nature, three-fourths of all elements in nature are hydrogen. Abundance can be developed because it can be converted into electrical energy and is expected to be able to replace fossil materials that are increasingly depleting in the future. For the management of hydrogen, a very safe storage is needed. One of the efforts by inserting hydrogen in certain metals. Magnesium is one material that is able to absorb hydrogen. But it has a disadvantage, namely the absorption and release time is very slow, this is due to the strong bond between hydrogen and magnesium. Several attempts have been intensively studied to improve the properties of Magnesium including the use of materials in the form of nanocrystals with Mechanical alloying techniques and efforts to add certain catalysts are now being actively studied. Research on the addition of Hematite (Fe2O3) catalysts to hydrogen storage materials has been carried out through Mechanical alloying techniques based on MgH2-Fe2O3. Hematite purely derived from nature has been successfully extracted chemically (precipitation method). The milled MgH2-Fe2O3 alloy samples were then analyzed by XRD and showed that the MgH2-Fe2O3 material was successfully reduced to the nanocrystal scale. The addition of catalysts and extended milling time also showed a decrease in desorption temperature.</p>

Structural and Thermal Study of Mg2TiO4 Nanoparticles Synthesized by Mechanical Alloying Method

2020 ◽  
Vol 12 (2) ◽  
pp. 87-91
Author(s):  
Ranjan K. Bhuyan ◽  
D. Pamu ◽  
Basanta K. Sahoo ◽  
Ashish K. Sarangi
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Particle Size ◽  
Mechanical Alloying ◽  
Communication Systems ◽  
Milling Time ◽  
Microstructural Analysis ◽  
High Energy ◽  
Gravimetric Analysis ◽  
Energy Ball

Background: Mg2TiO4 – based ceramics have proven their potentiality in the field of wireless communication systems. In the past, Mg2TiO4 ceramics was considered a quite optical response material in thin film form. Moreover, there is very few studies have been done whatever the proposed work in the present study. Objective: To prepare Mg2TiO4 nano-powders with the help of High Energy Ball Mill (HEBM) and intend to investigate its effect on crystal structure, microstructure and on thermodynamic behavior of MgO-TiO2 system. Methods: Mg2TiO4 ceramics were synthesized using Mechanical alloying method from high- purity oxides MgO and TiO2 (99.99%) of Sigma Aldrich (St. Louis, MO). Results: From the experimental studies it is observed that the powder’s particle size decreases with an increase of milling time. XRD analysis is carried out for phase confirmation of the mixed Mg2TiO4 powder. Further, the result also showed that there is structural changes occurred in the sample by high energy ball milling process, milled at different times. The nanocrystalline nature Mg2TiO4 powder was confirmed from microstructure taken by Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). Further, differential thermal gravimetric analysis has been carried out to investigate the thermal behavior of milled Mg2TiO4 -powder (35 hours). Conclusion: In work, the effect of mechanical alloying on structural, microstructural and thermal properties of nanocrystalline Mg2TiO4 powders has been investigated systematically. The effect of milling time on particle size, crystal structure and the microstructure was studied using XRD, FE-SEM, TEM and DSC/TGA analysis. The microstructural analysis (FE-SEM and TEM) reveals the nanocrystallinity nature of MTO ceramics prepared by mechanical alloying method. The thermal decomposition behavior of the milled powders was examined by a Thermo-Gravimetric Analyzer (TGA) in argon atmosphere.

Magnetic Properties of Mechanically Alloyed Nano-Crystalline Cu/Fe Composites

1992 ◽  
Vol 274 ◽  
Author(s):  
C. P. Reed ◽  
S. C. Axtell ◽  
R. J. De Angelis ◽  
B. W. Robertson ◽  
V. V. Munteanu ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Composite Structures ◽  
Milling Time ◽  
Composite Films ◽  
High Energy ◽  
Metal Powders ◽  
Nano Composite ◽  
Diffraction Profile

AbstractMetal powders of the composition 70 at% Cu and 30 at% Fe were produced by high energy mechanical alloying of the elemental powders. The powders were processed in a Spex 8000 mixer/mill for various times to investigate the potential of the mechanical alloying process for producing nano-composite structures with modified magnetic properties. Optical microscopy revealed a layered structure of alternating copper and iron that developed upon milling. The spacing between the layers decreased with milling time, becoming optically unresolvable (< 1 μm) after four hours of milling. A single profile x-ray diffraction profile shape analysis technique was used to determine the average diffracting particle size of the copper and iron phases. The diffracting particle size decreases with alloying time reaching values of 7.5 nm and 2 nm, for copper and iron respectively, after eight hours of alloying. The magnetic coercivity increased with milling time initially, reaching a maximum value above 300 Oe after six hours of milling. These results are discussed and compared to results obtained in Ag/Fe and Cu/Fe nano-composite films.

Fabrication of MoSi2 Nanocrystal by Mechanical Alloying Large Particle-Sized Starting Powders

2010 ◽  
Vol 434-435 ◽  
pp. 768-770
Author(s):  
Jun Ting Luo
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Powder Mixture ◽  
Large Particle ◽  
Milling Time ◽  
Average Grain Size

The MoSi2 nanocrystal was prepared by mechanical alloying (MA) large particle-sized starting powders, in which the milling time is much longer than usual MA time. It was found that the Mo-Si powder mixture mixed at stoichiometry proportion forms α-MoSi2 and β-MoSi2 in the MDR mode rather than pure α-MoSi2 in the SHS mode. The grain size of MoSi2, calculated using Scherrer′s formula, is 18nm when milled for 96h, and decreases to 12nm when further milling to 144 h. This is because that the milling balls provide enough energy to refine most of the rough crystal grain. The average grain size increased to 15nm when milled for 192 h, which indicates that further expand time could not refine the crystal grain while cause the growth of a part of the crystal grain. The particle size of MoSi2 is about 0.5μm when milled for 96 h and the agglomerating phenomenon is severe. The particle size of MoSi2 decreases to 0.4μm and releases the agglomerating phenomenon with the milling time for 144 h.

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