The effect of process control agent usage on the structural properties of MgB 2 synthesized by high energy ball mill

2017 ◽  
Vol 43 ◽  
pp. S391-S396 ◽  
Author(s):  
Haldun Kurama ◽  
Şavaş Erkuş ◽  
Hakan Gaşan
2008 ◽  
Vol 22 (18n19) ◽  
pp. 2933-2938 ◽  
Author(s):  
H. BAHMANPOUR ◽  
S. HESHMATI-MANESH

High energy ball milling was performed on a mixture of titanium and aluminum elemental powders with a composition of Ti -48(at.%) Al . Stearic acid was added to this powder mixture as a process control agent (PCA) to study its effect on the microstructure evolution and crystallite size of the milled powder after various milling times. Phase compositions and morphology of the milled powders were evaluated using X-ray diffraction and scanning electron microscopy. Crystallite sizes of milled powders were determined by Cauchy-Gaussian approach using XRD profiles. It was shown that addition of 1wt.% of stearic acid not only minimizes the adhesion of milling product to the vial and balls, but also reduces its crystallite sizes. It has also a marked effect on the morphology of the final product.


2003 ◽  
Vol 416-418 ◽  
pp. 144-149 ◽  
Author(s):  
Cláudio José da Rocha ◽  
Ricardo Mendes Leal Neto ◽  
Valéria S. Gonçalves ◽  
L.L. Carvalho ◽  
Francisco Ambrozio Filho

2007 ◽  
Vol 119 ◽  
pp. 147-150 ◽  
Author(s):  
Chang Woo Kim ◽  
Young Hwan Kim ◽  
Don Keun Lee ◽  
In Chul Jeong ◽  
Hae Woong Kwon ◽  
...  

We report the core/shell type as the interesting one of the various techniques to prepare exchange-coupled permanent magnet. In this study, the exchange-coupled Nd2Fe14B/α-Fe was prepared by high energy ball mill process and chemical reduction. Nd15Fe77B8 powder prepared by high energy ball mill process was coated with α-Fe nanoparticle by chemical reduction. α-Fe nanoparticle on the ball milled Nd15Fe77B8 was synthesized by chemical reduction with borohydride as a reducing agent in aqueous solution. After annealing, Nd2Fe14B/α-Fe forming core/shell shape has exchange-coupling effect and was identified by using XRD, FE-SEM, VSM, TMA and EDX.


2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE

In this paper, the influence of toluene as the process control agent (PCA) and pre-milling on the extension of solid solubility of 7 wt.% Cr in Cu by mechanical alloying in a high energy ball mill was investigated. The structural evolution and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The solid solution formation at different conditions was analyzed by copper lattice parameter change during the milling process. It was found that both the presence of PCA and pre-milling of Cr powder lead to faster dissolution of Cr . The mean crystallite size was also calculated and showed to be about 10 nm after 80 hours of milling.


2019 ◽  
Vol 810 ◽  
pp. 101-106 ◽  
Author(s):  
Petr Haušild ◽  
Jaroslav Čech ◽  
Veronika Kadlecová ◽  
Miroslav Karlík ◽  
Filip Průša ◽  
...  

In this paper, recently developed ternary FeAl20Si20 (wt.%) alloy with promising high-temperature oxidation and wear resistance was prepared by mechanical alloying in a high-energy ball mill. The possibility to speed-up the mechanical alloying process by replacing aluminium (and partly silicon) elemental powder by the pre-alloyed powder (AlSi30) with relatively fine dispersion of Si in the Al-Si eutectic was examined. The microstructure, phase composition and mechanical properties after various time of mechanical alloying were characterized. The effect of using the pre-alloyed powders on kinetics of mechanical alloying is compared with the results obtained on batches prepared from elemental powders.


2019 ◽  
Vol 969 ◽  
pp. 68-72
Author(s):  
K. Chandra Sekhar ◽  
Balasubramanian Ravisankar ◽  
S. Kumaran

An attempt was made to synthesis Al-5083alloy through high energy ball milling and densification through ECAP. The elemental powders consisting of Al5083 was milled for 5, 10 and 15 hrs using Retsch high energy ball mill (PM400). The physical and structural properties of mechanically alloyed particulates were characterised by diffraction methods and electron microscopy. The 15hrs nanocrystalline structured particulates of Al5083 alloy shows crystallite size of 15nm. Scanning Electron Microscope (SEM) reveals the morphology of alloy which is irregular shaped. The size of alloyed particulates also measured using SEM and found to be 7μm for 15hrs of milling. The 15hr milled alloy particulates were densified by ECAP through 90o die channel angle. Maximum densification of 92% and highest hardness of 63HRB was achieved for sample consolidated with route-A for two passes along with sintering.


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