Comparative Study of Mechanical Activation Improved by High Energy Ball Mills in Chromium Oxide Reduction

2014 ◽  
Vol 802 ◽  
pp. 41-45
Author(s):  
Mauricio de Castro ◽  
Osvaldo Mitsuyuki Cintho ◽  
José Deodoro Trani Capocchi
Keyword(s):  
Thermal Analysis ◽  
Mechanical Activation ◽  
Chromium Oxide ◽  
Power Supply ◽  
High Energy ◽  
Planetary Mill ◽  
Oxide Reduction ◽  
Ball Mills ◽  
Energy Ball ◽  
Unconventional Methods

The processes of high-energy milling and gained importance among the unconventional methods. In this work, we seek to compare the power supply two types of high energy mills (vibratory mill (SPEX) and planetary mill) with the variation of the milling power. The millings were carried out with a mixture of chromium oxide and aluminum metalic. The reduction of chromium oxide does not occur instantaneously, but gradually as the progress of milling with mechanical activation of powders, this mechanical activation occurs leading to the solid state reaction occurs. The results were obtained for thermal analysis of the samples. The energy released varies, exhibiting a maximum mechanical activation for the range of powers milling studied. The correlation between the energy mills can be made by identifying the milling power is reached at which the maximum in each mechanical activation mill and quantifying this activation.

scholarly journals Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
Nominal Composition ◽  
Mechanically Alloyed ◽  
Milling Parameters ◽  
Energy Ball ◽  
Full Conversion

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.

scholarly journals Influence of mechanical activation of AL2O3 on synthesis of magnesium aluminate spinel

2004 ◽  
Vol 36 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Zhang Zhihui ◽  
LI. Nan
Keyword(s):  
Grain Size ◽  
Mechanical Activation ◽  
Bulk Density ◽  
Milling Time ◽  
High Energy ◽  
Magnesium Aluminate ◽  
Reaction Sintering ◽  
Air Atmosphere ◽  
Energy Ball ◽  
Analytical Reagent

Magnesium aluminate (MA) spinel is synthesized by reaction sintering from alumina and magnesia. The effects of mechanical activation of Al2O3 on reaction sintering were investigated. Non-milled a - Al2O3 and a - Al2O3 high-energy ball milled for 12h, 24h and 36h were mixed with a MgO analytical reagent according to the stoichiometric MA ratio, respectively and pressed into billets with diameters of 20mm and height of 15mm. The green-body billets were then sintered at high temperature in an air atmosphere. The results show that bulk density, relative content of MA and grain size of MA increase with increasing high-energy ball milling time of Al2O3. However prolonged milling time over 24h has a small beneficial effect on the densification of MA. Bulk density and grain size of a sample of a- Al2O3 milled for 24h are 3.30g/cm3 and 4-5 mm, respectively.

Mechanochemical Synthesis of Intermetallic Compounds in the Gallium–Iridium System

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940067
Author(s):  
P. Vitiaz ◽  
N. Lyakhov ◽  
T. Grigoreva ◽  
E. Pavlov
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Activation ◽  
Intermetallic Compounds ◽  
High Energy ◽  
Planetary Mill ◽  
X Ray Diffraction ◽  
X Ray ◽  
Active Liquid ◽  
Scanning Electron

The interaction between a solid inert metal Ir and an active liquid metal Ga during mechanical activation in a high-energy planetary mill is studied by X-ray diffraction and scanning electron microscopy with high-resolution energy dispersive X-ray microanalysis. The effect of mechanical activation on the formation of GaxIry intermetallic compounds and GaxIry/Ir composites and their solubility in acids was investigated. The subsequent extraction of Ga from intermetallic compounds and composites in the mixture of concentrated acids [Formula: see text] makes it possible to produce nanoscale Ir.

Microstructural Transformations of Al2O3-TiO2 and Al2O3-ZrO2 Powders Induced by High-Energy Ball-Milling

2006 ◽  
Vol 45 ◽  
pp. 303-308
Author(s):  
Sandrine Coste ◽  
Ghislaine Bertrand ◽  
Christian Coddet ◽  
Eric Gaffet ◽  
Horst Hahn ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Milling Time ◽  
Tetragonal Zirconia ◽  
Rutile Phase ◽  
High Energy ◽  
Planetary Mill ◽  
Energy Ball ◽  
Yttria Partially Stabilized Zirconia ◽  
Tio2 Phase ◽  
Zro2 System

Superior properties of nanostructured Al2O3 based materials, such as higher hardness and fracture toughness, have been evidenced. In order to optimize their manufacturing, the mechanical activation of the starting powders (Al2O3-TiO2 and Al2O3-ZrO2) was studied. In the present work, Al2O3 powders blended with 13wt% and 44wt% of titania or 20wt% and 80wt% of yttria partially stabilized zirconia have been high-energy ball-milled using a planetary mill, P4 (Fritsch) with steel vials and balls. The effect of the milling time and operating parameters, such as shock energy and friction to total energy ratio, on the powder structural and microstructural evolutions has been determined by SEM, XRD and BET. The transformation of the metastable anatase TiO2 phase into the high pressure TiO2 II phase and rutile phase was evidenced, simultaneously to the decrease of the alumina crystallite size, in the Al2O3-TiO2 system. In the Al2O3-ZrO2 system, the transformation of the monoclinic phase and the decrease of the alumina and tetragonal zirconia crystallite size have been observed.

Variation of Tungsten Oxide Reduction Mode Using Different High Energy Milling Conditions

2012 ◽  
Vol 727-728 ◽  
pp. 206-209
Author(s):  
Osvaldo Mitsuyuki Cintho ◽  
H.I. Tsai ◽  
M. Bär ◽  
M. de Castro ◽  
E.F. Monlevade ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Milling Time ◽  
Xrd Analysis ◽  
High Energy ◽  
Oxide Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball ◽  
Fast Increase ◽  
Stoichiometric Proportion

High energy ball milling has been used like alternative route for processing of materials. In the present paper, the reduction of tungsten oxide by aluminum in order to obtain metallic tungsten was studied using a SPEX type high energy mill. A powdered mixture of WO3and metallic aluminum, weighed according to the stoichiometric proportion with an excess 10% Al, was processed with hardened steel utensils using a 1:6 powder-to-ball ratio. The processing was carried out with milling jar temperature measurement in order to detect the reaction type. The temperature evaluation indicated the self-propagating reaction occurrence by fast increase of the jar temperature after a short milling time. The tungsten oxide reduction was verified by X-Ray Diffraction (XRD) analysis and the milling products were characterized by Scanning Electron Microscopy (SEM). The results were slightly different from the literature due to the mill type and milling parameters used in the work.

Nickel Silicides Synthesized by High Energy Ball Milling

2007 ◽  
Vol 353-358 ◽  
pp. 1625-1628 ◽  
Author(s):  
Gen Shun Ji ◽  
Qin Ma ◽  
Tie Ming Guo ◽  
Qi Zhou ◽  
Jian Gang Jia ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Microstructure Morphology ◽  
Energy Ball ◽  
Xrd Patterns

The high energy ball milling of Ni-50 atom % Si elemental powder mixtures was carried out using a planetary mill. X-ray diffraction (XRD) was used to identify the phase evolutions during the high energy ball milling period. The microstructure morphology of the powders milled different time was determined by field emission scanning electron microscope (FESEM). The beginning time of mechanical alloying was determined by back scattered electrons (BSE) images. The XRD patterns showed that the nickel peaks intensity and the silicon peaks intensity obviously decreased with milling time increased to 1 hour. BSE images revealed that nickel and silicon powders were not blended uniformly for 1 hour of milling. It was found that NiSi formed as the milling time increased to 5 hours, simultaneously, the nickel peaks and the silicon peaks almost disappeared. That means the obvious mechanical alloying started from 5 hours of milling. BSE images agreed with the result analyzed from XRD patterns. With the milling time further increased from 10 to 75 hours, the NiSi peaks decreased gradually, at the same time, the Ni2Si peaks appeared and then increased gradually.

scholarly journals Structure and ion dynamics of mechanosynthesized oxides and fluorides

2017 ◽  
Vol 232 (1-3) ◽  
Author(s):  
Martin Wilkening ◽  
Andre Düvel ◽  
Florian Preishuber-Pflügl ◽  
Klebson da Silva ◽  
Stefan Breuer ◽  
...  
Keyword(s):  
Ion Transport ◽  
Short Review ◽  
High Energy ◽  
Ion Dynamics ◽  
Ball Mills ◽  
Local Structures ◽  
Equilibrium Structures ◽  
Energy Ball ◽  
Metastable Compounds ◽  
Preparation Techniques

AbstractIn many cases, limitations in conventional synthesis routes hamper the accessibility to materials with properties that have been predicted by theory. For instance, metastable compounds with local non-equilibrium structures can hardly be accessed by solid-state preparation techniques often requiring high synthesis temperatures. Also other ways of preparation lead to the thermodynamically stable rather than metastable products. Fortunately, such hurdles can be overcome by mechanochemical synthesis. Mechanical treatment of two or three starting materials in high-energy ball mills enables the synthesis of not only new, metastable compounds but also of nanocrystalline materials with unusual or enhanced properties such as ion transport. In this short review we report about local structures and ion transport of oxides and fluorides mechanochemically prepared by high-energy ball-milling.

Pack-Aliting in Thermitic Powder Mixture Obtained by Mechanical Alloying

2018 ◽  
Vol 69 (8) ◽  
pp. 2092-2096
Author(s):  
Mihai Branzei ◽  
Leontin Nicolae Druga ◽  
Florica Tudose ◽  
Roxana Trusca ◽  
Mihai Ovidiu Cojocaru
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Reduction Reaction ◽  
Treatment Temperature ◽  
Ball Mills ◽  
Mechanically Alloyed ◽  
Aluminum Powders ◽  
Energy Ball ◽  
Nonferrous Alloys

The paper deals with the effects of the structural state modification of the main pulverulent component used for the alloying of metallic products made of steels, cast iron or nonferrous alloys, on the layers kinetics formation. The aliting process is most often done in a powdery mixtures, composed of three components: the active component providing aluminum, a neutral one with the role of dispersing the others, also having the role of blocking the sintering tendency and a halide as an activator, by cleaning the metal surfaces to be saturated. The aim of the paper is to present the ways to ensure the kinetics of the aliting layer formation, while reducing the heat treatment temperature. These could be accomplished by replacing the aluminum or ferroaluminum powder with equimassic amounts mixture of thermitic powders, consisting of ferrous oxides and aluminum powders, mechanically alloyed in high energy ball mills. Thus, it is possible to produce the aluminothermic reduction reaction in the component obtained by mechanical alloying at the same time generating notable thermal effects.

Synthesis of Nanostructured Bismuth Ferrite by Mechano-Thermal Route

2013 ◽  
Vol 829 ◽  
pp. 722-726 ◽  
Author(s):  
Mostafa Ahmadzadeh ◽  
Abolghasem Ataie ◽  
Ebrahim Mostafavi
Keyword(s):  
Mechanical Activation ◽  
Bismuth Ferrite ◽  
High Energy ◽  
Molar Ratio ◽  
Heat Treated ◽  
Multiferroic Bifeo ◽  
Milled Sample ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
The Mean

In this study, multiferroic BiFeO3 (BFO) powders were synthesized via mechanical activation of Bi2O3 and Fe2O3 with the molar ratio of 1:1, using a planetary high energy ball mill and subsequent heat treatment. All samples were milled for 20 h and heat treated at various temperatures. XRD, FESEM, LPSA, and VSM techniques were used to evaluate the powder particle characteristics. FESEM images of 20 h milled sample indicated plate-like particles with a mean thickness of 45 nm and its LPSA results showed the mean agglomerate size of about 2.0 μm. XRD results of calcined samples showed that the BFO phase began to form at 650 °C and fully formed at 750 °C. In comparison to the conventionally processed samples, BFO phase formation temperature decreases by 100 °C in the samples produced by mechanical activation assisted process. VSM measurements of the sample heat treated at 750 °C revealed a saturation magnetization (Ms) of 0.054 emu/g and coercivity (Hc) of 412 Oe.

Synthesis of TiFe Compound from Ball Milled TiH2 and Fe Powders Mixtures

2014 ◽  
Vol 802 ◽  
pp. 61-65 ◽  
Author(s):  
Railson Bolsoni Falcão ◽  
Edgar Djalma Campos Carneiro Dammann ◽  
Cláudio José da Rocha ◽  
Rodrigo Uchida Ichikawa ◽  
Michelangelo Durazzo ◽  
...  
Keyword(s):  
Profile Analysis ◽  
High Vacuum ◽  
High Energy ◽  
Planetary Mill ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
Sample Number ◽  
Heat Treated ◽  
Crystallite Sizes ◽  
Energy Ball

TiFe compound was produced by high-energy ball milling of TiH2and Fe powders, followed by heating under vacuum. TiH2was used instead of Ti in order to avoid the strong particles adhesion to grinding balls and vial walls. Mixtures of TiH2and Fe powders were dry-milled in a planetary mill for times ranging from 5 to 40 hours. The amount of sample, number and diameter of the balls were kept constant in all experiments. After milling, samples were heated under dynamic high-vacuum for the synthesis reaction. As-milled and heat-treated materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The mean crystallite sizes and microstrains were determined by XRD line profile analysis using the Warren-Averbach method. As-milled materials presented only Fe and TiH2phases. Nanostructured TiFe compound was formed after heat treatment. TiH2was effective for providing low adherence of the powders during milling.

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