Chemical Engineering Journal, Vol.256, 32-38, 2014
Nano-sized boron synthesis process towards the large scale production
In the present paper a new process for large scale production of nano-sized boron is reported. The process can be summarized in several steps: boron oxide solubilization in hot water, cryogenic freezing of liquid phase, freezing-drying process, magnesiothermic reduction of boron oxide, boron purification. Each step is described in order to show the innovations and then the purified boron has been employed to synthesize the superconducting MgB2 powder. It is worth to note that for the first time the same MgB2 precursors were used to prepare the superconducting phase following four different techniques and the results directly compared. So several MgB2 conductors were prepared applying different techniques, ex-situ, in-situ, via MgB4 and RLI, and then their superconducting properties investigated. Furthermore morphology, grain size and purity of B and MgB2 powder were analyzed by SEM analysis and X-ray diffraction technique. (C) 2014 Elsevier B.V. All rights reserved.