Sintering Behavior and Activation Energy of Fe₂O₃ Nanoparticles: A Molecular Dynamics Research

Abstract

In this article, molecular dynamics was used to simulate the sintering process of nanoparticle Fe₂O₃ at 1423 K, 1523 K, 1623 K and 1723 K. The crystal connection evolution process between the nanoparticles was extracted, and the activation energy under different sintering mechanisms was calculated using the model function combined with the Arrhenius formula. The results show that as the sintering temperature rises, so does the crystal connection speed and that in the early stages of sintering the atomic diffusion motion becomes progressively more intense with increasing temperature, but that after the temperature rises to 1623 K, the motion no longer changes significantly. The calculated activation energy for each diffusion mechanism is 134.04 kJ mol⁻¹ for viscous flow or plastic flow, 168.74 kJ mol⁻¹ for evaporation-condensation, 267.48 kJ mol⁻¹ for lattice (volume) diffusion, 285.03 kJ mol⁻¹ for grain boundary diffusion and 367.45 kJ mol⁻¹ for surface diffusion. The calculated findings reveal that the mechanism function fits well, and particle migration in the early densification process of sintering is more dependent on surface diffusion.