Gamma irradiation‐induced structural degradation and dielectric response of B ₄ C nanoparticles

Abstract This study investigates the structural, optical, and dielectric properties of B 4 C nanoparticles exposed to gamma irradiation at doses from 25 to 150 kGy. X‐ray diffraction analysis showed an initial increase in crystallite size (up to 27.5 nm), followed by a reduction (to 22.2 nm) and non‐linear strain behavior. Raman and Fourier‐transform infrared spectra indicated bond weakening and partial amorphization. Field emission scanning electron microscopy revealed surface roughening and agglomeration, especially beyond 100 kGy. Optical reflectance data showed a red‐shifted absorption edge at low doses, associated with defect states, and band edge recovery at higher doses, likely due to structural disorder and band tailing. Dielectric measurements demonstrated increasing loss tangent and electrical conductivity with dose, attributed to defect‐enhanced charge transport. These results confirm that gamma irradiation induces dose‐dependent structural and functional changes in B 4 C, providing insights for applications in radiation‐intensive environments such as nuclear and aerospace systems.