| Abstract: |
Nanoparticles are of great interest in energy area for a wide range of applications. A variety of techniques are available for their synthesis and among these methods, thermal plasma approach offers continuous production of high purity nanoparticles in large scale where the particle size is usually less than 100 nm. In this technique, precursors, which are normally powders, are fed to the thermal plasma where they are evaporated and nanoparticles are derived from condensation of this vapor in the quenching zone. In this study, a 30 kW RF thermal plasma system was used. The system consist of a torch, nanopowder reaktor,has currently a nanopowder reactor but when needed could be replaced by a coating chamber or a spheroidization unit. The system was configured with injection probes which were located axially in the reactor, one from the top and the other from the bottom. This allowed injection of precursor powders into different temperature zones of the plasma. In the current study, nanoparticles in Mg-Ni binary system were produced. This involved Ni, Mg and Mg2Ni. Ni nanoparticles can be produced at ease yielding particles less than 100 nm in size. Moreover, when Ni was fed together with methane, Ni particles could be encapsulated with 6-10 layers of graphite yielding a core-shell structure. Mg2Ni intermetallic nanoparticles could be synthesized from elemental powders when Ni was fed from the top injector and Mg was fed through the bottom injector which was positioned just below the quenching zone in the reactor. The weight fraction of Mg2Ni could be as high as 55 wt%. The use of thermal plasma in the synthesis of metallic nanoparticles was discussed especially with regard to intermetallic alloys.
|
|
