Mechanically Activated Combustion Synthesis of B4C-TiB2 Nanocomposite Powder

In this study, in situ synthesis of B4C-TiB2 nanocomposite powder was performed by mechanically activated combustion synthesis method. The molar ratio of B2O3:TiO2:Mg:C was 3:1:12:1 to obtain the B4C-TiB2 nanocomposite. The milling process was used to mechanically activate the raw materials. Synthesis of prepared samples occurred in a furnace under argon atmosphere at 900 ºC. The milling parameters were examined to optimize the activating process of the raw materials. The specimens were studied in various steps by XRD analysis for evaluation of phase compositions. Initially, the synthesized samples contained MgO, B4C, TiB2 and a small amount of magnesium borates. XRD analysis after acid leaching of the combustion products showed a great effect of acid leaching on removing the impurities. It was demonstrated that mechanical activation is a useful method for simultaneous obtaining of B4C and TiB2 powders . Morphology of the synthesized products was investigated by scanning and transmission electron microscopies (SEM & TEM). The final products were synthesized with a homogeneous morphology. The SEM analysis showed that the sample with 12 h of milling is made up of more uniform grains with smaller particle sizes (˂ 100 nm) than the sample with 6 h of milling.