The effects of mechanical activation of a powder mixture of basic talc and periclase on the reaction rate of the formation of the forsterite structure were studied in the absence and presence of fluorine and chlorine ions. Mechanical activation with fluorine/chlorine ions caused the formation of a series of intermediate transition compounds in an explosive reaction that enhanced the forsterite fabrication rate. Fluorine/chlorine ions were released from the system by hydrolysis. Single-phase nanocrystalline forsterite powder was successfully synthesized by 1 h of mechanical activation with subsequent annealing at 1000 and 1200 oC for 1 h in the presence of fluorine ions. In the presence of chlorine ions, single-phase forsterite powder was obtained after 1 h of mechanical activation with subsequent annealing at 1200 oC for 1 h, but the crystallite size of this sample was larger than 100 nm. In the absence of these ions, forsterite can be fabricated by 5 h of mechanical activation with subsequent annealing at 1000 oC for 1 h.

Keywords: Mechanical activation, Forsterite, Nanostructure materials, Fluorine ions, Chlorine ions.