Enhancement of self-sustaining reaction Cu3Si phase formation starting from mechanically activated powders

Mechanical high-energy ball milling of an 3Cu + Si elemental powders mixtur e was used to activate a self-sustaining combustion reaction or so-called s elf-sustaining high-temperature synthesis (SHS) to form the copper silicide phase, a reaction for which the thermodynamic criterion proposed by Munir for self-propagation reaction is not favorable. A complete characterization of the end-products was performed with X-ray diffraction analysis and scan ning electron microscopy. Thermal and structural information describing the combustion front initiated by heating up a sample to 180 degrees C in a Cu /Si system is communicated. This paper clearly shows that the mechanically activated self-sustaining high-temperature synthesis process produces a pur e Cu,Si compound in spite of the limitation imposed by the thermodynamic cr iterion. In addition, it stems that the reactivity of Cu,Si elaborated from the mechanically activated SHS process towards CuCl is greater than the re activity of Cu,Si reference powder. This difference is mainly due to the cr ystallite size. (C) 2000 Elsevier Science S.A. All rights reserved.