Synthesis and Spark Plasma Sintering of Mg sub(2)Si Nanopowder by Mechanical Alloying and Heat Treatment

In this investigation, a two-step method for the preparation of magnesium silicide (Mg sub(2)Si) nanopowder was studied. This method is known as mechanical alloying followed by heat treatment. The results showed that the compositions of the combustion products depended on the milling time, heat treatment temperature, and starting mixtures. Pure Mg sub(2)Si nanopowder was formed after short milling time and heat treatment, from Mg and Si powders with the mole ratio of 2.1:1 (Mg:Si) at 500 degree C in Ar atmosphere. Using the Mg sub(2)Si nanopowder, Mg sub(2)Si ceramic was produced by spark plasma sintering at 800 degree C under 50 MPa for 15 min. Composition and structure of reactants and products were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM).