P. Delshad-Khatibi, F. Akhlaghi,
Volume 28, Issue 1 (Jun 2009)
Abstract
Solid Assisted Melt Disintegration (SAMD) is a relatively new method for producing metallic powder particles in which the kinetic energy transferred from a rotating impeller to the melt via a solid medium causes melt disintegration. These droplets are then solidified and separated from the media to obtain metallic powder particles. In the present study, sodium chloride (NaCl) was used to produce Al-6wt%Si powder particles. A specified amount of NaCl was introduced into the aluminum alloy melt and the slurry was stirred following a specified time-temperature regime to disintegrate the molten alloy into droplets. This blend was quenched in water to solidify Al powder particles and to dissolve NaCl in water. The Al powder particles were then collected, washed, dried, and subjected to laser particle size (LPS) analysis and scanning electron microscopy (SEM). The effects of different time-temperature regimes on the size and morphology of the resultant Al-6wt%Si powder particles were investigated and the optimum conditions for obtaining the finest spherical particles were established. It was concluded that the finest and most spherically shaped Al powder particles could be produced by stirring the slurry at 690 °C for 5 min followed by water quenching.
F. Delshad, M. Maghrebi, M. Baniadam,
Volume 40, Issue 2 (Journal of Advanced Materials-Summer 2021)
Abstract
Carbon nanotubes contain impurities and deamorphization is one of the methods of their purification. In this study, for the first time, a solution of piranha with a ratio of 3:1 (30 ml sulfuric acid + 10 ml hydrogen peroxide) as well as microwave irradiation with processing time of 30 minutes were used to remove amorphous carbon from the nanotube arrays. Ultrasonication was performed to disperse pristine and purified carbon nanotubes in water and centrifugation was performed to separate large particles. To assess the removal of amorphous carbon, new characterization methods such as dispersed percent and floating percent were used. It was observed that with increase in the ultrasonication time (from 0 to 50 minutes), the dispersed percentage of treated arrays was increased (about 47%), while the floating percentage of pure array decreased (about 20%). These results are ascribed to the removal of amorphous carbon. The results of the thermo gravimetric analysis (TGA) were in good agreement with the results obtained from the newly proposed characterization methods.
