In this study, in situ synthesis of B4C-SiC nanocomposite powder (1 : 1 molar ratio) was performed by mechanically activated volume combustion synthesis (MAVCS) method. Raw materials were included Si, C, B2O3 and Mg. Milling process was used to mechanically activate the raw materials. Synthesis of prepared samples was occurred in a tube furnace under argon atmosphere at 1000 oC. The milling parameters were examined to optimize the activating of the raw materials process. Synthesized samples after mechanical activation with milling parameters of 300 rpm rotation speed, 20 to 1 ball to powder ratio and milling time of 9 and 12 h had best phase and morphology conditions. Average crystallite size of B4C and SiC compounds were calculated less than 15 nm for these two samples. Transmission electron microscopy (TEM) analysis of these two samples approved their formation from the grains in nanometers scale. The TEM analysis showed the sample with 12 h of milling the raw materials has formed from more uniform grains than the sample with 9 h of milling the raw materials. Particle size analysis showed more than 99% of the particles from both samples have a size less than 1000 nm.

Keywords: Volume combustion synthesis, Mechanical activation, B4C-SiC composite, nanocomposite powder, Phase evaluation, Morphology.