Papers by Keyword: High-Energy Ball Milling (HEM)

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Authors: Sandrine Coste, Ghislaine Bertrand, Christian Coddet, Eric Gaffet, Horst Hahn, H. Sieger, M.A. Rodriguez, Cathy Meunier, Serge Vives
Abstract: 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.
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Authors: Helio R. Simoni, Eduardo Saito, Claudinei dos Santos, Felipe Antunes Santos, Alfeu Saraiva Ramos, Olivério Moreira Macedo Silva
Abstract: In this work, the effect of the milling time on the densification of the alumina ceramics with or without 5wt.%Y2O3, is evaluated, using high-energy ball milling. The milling was performed with different times of 0, 2, 5 or 10 hours. All powders, milled at different times, were characterized by X-Ray Diffraction presenting a reduction of the crystalline degree and crystallite size as function of the milling time increasing. The powders were compacted by cold uniaxial pressing and sintered at 1550°C-60min. Green density of the compacts presented an increasing as function of the milling time and sintered samples presented evolution on the densification as function of the reduction of the crystallite size of the milled powders.
701
Authors: Hua Chen, Tian Yu Zhang, X.Y Lu, Su Qiu Jia, Zhi Long Chai
Abstract: In this paper, TiH2-47Al-5Nb (at.%) and TiH2-47Al-7Nb(at.%) alloys were mixed and synthesized using TiH2, Al and Nb powders. The composition and morphology evolution of the mixed powder were systematically investigated during high energy ball milling. The results show obvious that structure change of the particle during milling, and amorphous, TiAl, Ti3Al and Ti2Al phases at nanoscale are formed. The addition of Nb shows an active influence on the decomposition of TiH2 and formation of TiAl-intermetallics. Compare with Ti-Al system alloy, the forming process of TiAl-intermetallics for TiH2-Al-Nb system alloy is different and slower. Ti2Al metastable phase formed after ball milling for 15 h in our experiments.
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Authors: Railson Bolsoni Falcão, Edgar Djalma Campos Carneiro Dammann, Cláudio José da Rocha, Ricardo Mendes Leal Neto
Abstract: This work reports the efforts to obtain TiFe intermetallic compound by high-energy ball milling of Ti and Fe powder mixtures. This process route has been used to provide a better hydrogen intake in this compound. Milling was carried out in a SPEX mill at different times. Strong adherence of material at the vial walls was seen to be the main problem at milling times higher than 1 hour. Attempts to solve this problem were accomplished by adding different process control agents, like ethanol, stearic acid, low density polyethylene, benzene and cyclohexane at variable quantities and keeping constant other milling parameters like ball to powder ration and balls size. Better results were attained with benzene and cyclohexane, but with partial formation of TiFe compound even after a heat treatment (annealing) of the milled samples.
329
Authors: H. Rojas-Chávez, Fidel Reyes-Carmona, Gabriel Plascencia, D. Jaramillo-Vigueras
Abstract: Synthesis of intermetallic PbSe induced by high-energy ball milling has been studied. Systematic analysis of transformation in the resulting phases of milling from 0 to 10 h has been traced by characterizing the microstructures in terms of morphology, crystallite size, and percentages of phases formed as a function of milling time. Results reveal the formation of two phases. Where the system of PbO-Se transforms gradually to PbSe. Complete transformation is achieved after 10 h of milling time. Study of particle structure by the Rietveld Method further corroborates the value of the nano-order crystallite diameters as evaluated from the microscopic studies.
69
Authors: Xiao Fei Wang, Xiao Lan Cai
Abstract: CNT-reinforced aluminum matrix composites was produced by high-energy ball milling, the effect of rotary speed and milling time on the particle size distribution,the density and hardness of CNT-aluminum matrix composites were studied,it was observed that the rotary speed and milling time have an important effect on the mechanical properties of the CNT-aluminum matrix composites.
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Authors: P.I. Paulin Filho, R.R. Corrêa
150
Authors: Antonio Hernando, P. Crespo, M.S. Flores, L. Del Bianco, F. Briones
447
Authors: Toshiyasu Nishimura, Xin Xu, Naoto Hirosaki, K. Kimoto, Yoo Yamamoto, Hiroaki Tanaka
Abstract: A commercial silicon nitride powder with oxide sintering additives was ground with high-energy ball mill to obtain nano-sized powder. Metallic aluminium powder was added as a grinding additive. Effect of high-energy ball milling was evaluated by X-ray diffraction analysis. After milling, height of background increased and peak height of silicon nitride decreased in XRD chart, which suggested that vitrification and/or decrease in grain size of silicon nitride occurred. The milled powders were sintered by spark plasma sintering system. Aluminium nitride was formed during sintering by reaction of aluminium and atmospheric nitrogen. Dense nano-ceramics, which were composed of silicon nitride and sialon, were obtained by sintering at 1550 oC.
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