Synthesis and Characterization of ZrC-ZrB2-SiC Composite Nano Powder

In this research, ZrC-ZrB2-SiC nanocomposite powder was synthesized by carbothermal and borocarbotermal reduction methods. Zirconium silicate was first milled for four hours. Then eight mixtures of raw materials were prepared. Finally, the samples were pyrolyzed at 800°C for two hours and then heat-treated at 1500°C for 30 minutes under an argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests were used to examine the microstructure of the samples. Examination of XRD test results showed the presence of two-phase ZrC and SiC and the absence of ZrB2 phase due to boron evaporation. It was found that by increasing the molar ratio to three times the molar value of boron oxide does,nt cause the formation of ZrB2 phase. In a sample containing four times the molar amount of boron oxide, a ZrB2 phase was formed, in addition to which the presence of an undesirable ZrO2 phase was also observed. As the molar ratio of boron oxide increases to eight times the molar, the amount of both of the ZrB2 and ZrO2 phases increased. Finally, it was found that the optimal powder due to the undesirable phase of ZrO2, the powder sample containing four moles of boron oxide. Using Anix software, it was found that the optimal powder crystal size for ZrC, ZrB2 and SiC was 51, 60 and 30 nm, respectively.