Production of MoSi 2 by mechanical alloying and self-propagating high temperature synthesis in the presence of copper was investigated. The parameters affecting MA process including the revolution rate of the cup, milling time, ball to powder ratio(BPR), and diameter and number of balls in the constant BPR were studied. The effect of copper presence on the products of MoSi 2 combustion synthesis, ignition and combustion temperature was also evaluated. Finally the effect of raw materials and mechanical activation in the presence of copper on combustion and ignition temperatures was analyzed. Results showed that with 250 rpm and long alloying times(32 hrs and more) meta-stable Mosi 2 (?-Mosi 2 ) was produced. But MoSi 2 production was not completed even after 60 hrs of milling. However, with 550 rpm, the conversion of raw materials to product was completed after 17 hrs of alloying. Type and quantity of products were different in 250 and 550 rpm for the same alloying time. No product was achieved with 120 min mechanical alloying and BPR =10:1. When BPR was 20:1, small amounts of ?-MoSi 2 was produced and with BPR =40:1 small amounts of ?-MoSi 2 and ?-MoSi 2 was observed. At constant BPR, by increasing the balls diameter, MoSi 2 was produced, and the amount of product increased using balls with different diameters. In combustion synthesis of MoSi 2 in the presence of copper it was observed that before the beginning of the combustion synthesis reaction, eutectic melt of Cu-Si forms in contact with the Mo particles. The reaction between Si in this melt and Mo particles increase the temperature. By melting Si particles and dissolving Mo and Cu in it, combustion synthesis reaction starts. Furthermore it was shown that Mo- and Si-rich silicide phases precipitate at the MoSi 2 grain boundaries and the amount of these phases increases with increasing the copper content. The ignition and combustion temperatures of mixture decreased and increased with increasing copper content, respectively. In samples containing the same copper content, combustion and ignition temperature decreased with increasing activation time.
