Physical and Electrochemical Properties of SiOx /C Composites Prepared by a Combination of Spray Pyrolysis and High Energy Ball Milling

2015 ◽  
Vol 1775 ◽  
pp. 7-12 ◽  
Author(s):  
Anara Molkenova ◽  
Izumi Taniguchi

ABSTRACTSpray pyrolysis has been widely used to prepare homogeneous and uniform ceramic powders with high purity. In this study, we are proposing ultrasonic spray pyrolysis followed by heat treatment to produce SiOx/C composite powders, where sucrose was used as a carbon source. Furthermore, high energy ball milling of the as-prepared powders in the presence of acetylene black was conducted to activate its electrochemical properties by reducing the particle size and improving the functionalization of the SiOx composite particles. SiOx/C nanocomposite finally obtained at a sucrous concentration of 0.1 mol L-1 showed superior electrochemical properties, and the SiOx/C nanocomposite electrode delivered the first discharge and charge capacities of 1252 and 819 mAh g-1, respectively, with an initial columbic efficiency of 65% at a current density of 50 mAh g-1 in the potential range from 0.01 to 3 V versus Li/Li+.

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.


2013 ◽  
Vol 762 ◽  
pp. 457-464 ◽  
Author(s):  
Riccardo Casati ◽  
Matteo Amadio ◽  
Carlo Alberto Biffi ◽  
David Dellasega ◽  
Ausonio Tuissi ◽  
...  

Metal matrix nanocomposites have been produced by powder metallurgy route. Al and nanoAl2O3powders were grinded through high energy ball milling. Then, the composite powders were sintered by Equal Channel Angular Pressing (ECAP). 12 ECAP passes were carried out in order to improve the dispersion of the hard particles. SEM analysis was performed to investigate the distribution of the ceramic nanoparticles within the matrix. Hardness tests were executed to evaluate the mechanical behavior of the nanocomposites. Finally, mechanical strength values obtained by numerical models were compared with those estimated from hardness measurements. High energy ball milling followed by ECAP process revealed to be a suitable route for the production of metal matrix composites reinforced with well dispersed nanoparticles.


2011 ◽  
Vol 319-320 ◽  
pp. 61-63 ◽  
Author(s):  
Xiu Yan Guo ◽  
Guo Jin Ma ◽  
Shi Kun Xie ◽  
Rong Xi Yi ◽  
Zhi Gao

Cu-4% mixed-powder consisting of rough copper powder and graphite powder was separately mechanical alloyed by high-energy ball milling. The phases and micrograph of these powders were determined by X-ray diffraction and scanning electron microscopy (SEM). The results show an increase in the lattice parameter of copper with milling times, up to a saturation value of about 24h; There was an absence of graphite reflections from X-ray diffractograms after longer milling times.


2011 ◽  
Vol 287-290 ◽  
pp. 1492-1495 ◽  
Author(s):  
Hai Xia Wang ◽  
Ping Zhan Si ◽  
Wei Jiang ◽  
Jin Jun Liu ◽  
Jung Goo Lee ◽  
...  

Novel nano-composite powders composed of hard-magnetic Mn54Al46 and soft-magnetic α-Fe were prepared by high-energy ball milling. The effect of α-Fe and preparation conditions on the structure and magnetic properties of the composite powders has been investigated. The ε-MnAl transforms to γ-MnAl, τ-MnAl, and β-phase under ball milling and annealing. The saturation magnetization and coercivity of the two-phase samples decrease with increasing temperature for the τ-phase decomposes at elevated temperatures. With increasing iron content, the coercivity decrease first and then increase up to 0.33 T when the Fe content is 10 wt%. Further addition of the magnetically soft iron phase would result in a decrease of the coercivity.


2016 ◽  
Vol 23 (3) ◽  
pp. 330-338 ◽  
Author(s):  
Lin-zhi Wang ◽  
Ying Liu ◽  
Wen-hou Wei ◽  
Xu-guang An ◽  
Tao Zhang ◽  
...  

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