Investigation of the formation of defects under fast neutrons and gamma irradiation in 3C–SiC nano powder

In this work cubic phase, silicon carbide nano-powders were irradiated at the high-flux pulsed reactor IBR–2 (Dubna, Russia). The 3C–SiC powder was irradiated with neutron doses up to 1015 n/cm2. The irradiated samples were then analyzed using X-ray diffraction, Raman spectroscopy, Positron annihilation spectroscopy, and Fourier Transform Infrared Spectroscopy. The XRD analysis showed a slight decrease in the lattice parameters with the increase in neutron fluences. The results obtained from positron annihilation measurements were compared to the theoretical calculations, to recognizing the type of structural defect in the samples. A positron lifetime component 355 ps associated with the calculated values for clusters containing of 13–21 vacancies was identified. The concentration of these defects was estimated to be in the region of 5 ppm, and was very similar to the one identified on the unirradiated sample. The results also indicate high irradiation resistivity of the 3C–SiC after irradiation. •Nano silicon carbide was irradiated fast neutron flux up to 1015 n/cm² and energy of neutron flux E≥1 MeV at room temperature.•A positron lifetime component 355 ps associated with the calculated values for clusters containing of 13 to 21 vacancies was identified.•At small fluences up to 1.3×1013 n/cm² the lattice parameters decrease from 4.3571 Å to 4.3527 Å is observed.