CORRELATION BETWEEN STRUCTURAL STABILITY, OXIDATION BEHAVIOR AND LATTICE DYNAMICS IN GAMMA-IRRADIATED TiN NANOPARTICLES

This study presents an integrated assessment of the crystal structure, post-irradiation oxidation behavior and vibrational response of titanium nitride (TiN) nanoparticles exposed to gamma radiation. Nanopowders with an average particle size below 20 nm were irradiated using a 60Co source at absorbed doses of 50, 200, 900 and 3500 kGy. Structural changes after annealing at 1173 K were examined by X-ray diffraction and Rietveld refinement, while dose-dependent lattice dynamics were evaluated by Raman spectroscopy in the 100–600 cm−1 range. The cubic Fm-3m structure remained stable throughout irradiation, and no radiation-induced phase transformation was detected. After annealing, rutile TiO2 was identified as a minor phase; its fraction decreased from 6.40 % in the unirradiated specimen to 3.88% after irradiation at 3500 kGy. High-dose irradiation followed by annealing reduced microstrain and dislocation density and increased the average crystallite size to approximately 50 nm. Four Raman modes near 152, 246, 359 and 500 cm−1 persisted at every dose, although their positions, widths and areas changed. The combined results show that gamma irradiation does not destabilize the TiN framework but modifies defects, interatomic distances and surface-bound species, thereby suppressing subsequent oxidation and altering the vibrational response.