Investigation of the effect of sample volume on the synthesis of B4C / SiC nanocomposite powder by mechanical activation volume combustion synthesis method assisted by spark plasma instrument

In this study, B4C / SiC nanocomposite powder with 1 to 1 molar ratio was synthesized completely in situ, with high purity and at low temperature by mechanical activation volume combustion synthesis method. At first, raw materials consist of B2O3, Mg, C and Si were weighed. The weighed materials were mixed and milled for 9 hours by planetary ball mil and under argon atmosphere. Milled materials were poured into cylindrical graphite molds with a diameter of 1.5 and 3 cm. The molds are placed in the plasma spark instrument. The synthesis in vacuum occurred at a temperature of less than 300 ° C and less than 3 minutes. After synthesis, a step of acid leaching by 1 molar HCl was applied to remove magnesium oxide. XRD, SEM and EDS analyzes were used to study the samples at different stages. The results of XRD and EDS analysis showed that the sample synthesized in a mold with a diameter of 3 cm (sample with greater volume) and then acid leached had a higher purity (more than 95%). The average crystalline size was calculated by the Sherer equation for each of the components of B4C and SiC, 68 and 57 nm, respectively. Particles of B4C-SiC nanocomposite with a size between 100 and 600 nm were observed in SEM and TEM analysis.