چكيده به لاتين
In this research the self-propagation combustion synthesis of Mg2Si has been studied. The reaction front propagation and effective parameters in combustion synthesis of Mg2Si has been investigated. For this purpose, cylindrical samples of compressed, mixed powders of Mg and Si with constant molar ratio of 2:1 and relative densities of 70, 80 and 90% have been prepared. The particle size distribution of silicon were 37-44, 44-105 and 105-250 microns. The combustion synthesis was carried out under argon atmosphere. Ignition of the samples took place using an induction coil and graphite. The temperature history of the samples was determined using K-type thermocouples which were embedded in particular locations in the samples. Temperature data was recorded using a set-up which was capable of collecting ten signals per second. All synthesized samples has been analyzed using X-ray diffraction, scanning electron microscopy, elemental and thermal analysis. The effect of relative density and particle size of silicon on the reaction front propagation velocity, combustion temperature and ignition time has been studied. It has been shown that with increasing of relative density and decreasing of silicon particle size the combustion temperature primarily increases and then decrease, also with increasing in the relative density, the combustion temperature increases after a decrease. The reaction front propagation velocity increases with increasing the relative density and decreasing the silicon particle size. Combustion synthesis activation energy for Mg2Si compound was calculated with modified Arrhenius equation using the reaction front propagation velocity and combustion temperature which was 195 kj/mol.
Keywords: silicide intermetallic, Mg2Si compound, self-propagation combustion synthesis, relative density, particle size, temperature history
