A molecular dynamics study concerning the effect of high-temperature and high-pressure on the structure and phase transition of Fe2O3 material

This paper uses Molecular Dynamics (MD) method to study the influence of high temperature (T) and high pressure (P) on the structure and phase transition of Fe₂O₃ materials. The results show that, when increasing the temperature from T = 300 K to T = 7000 K, P = 0.0 GPa, the size (1) of the Fe₂O₃ materials increases, the energy (E) increases, the length link (r) decreased, the number of structural units FeO₄, FeO₅ increased, and FeO₆ decreased. Similarly, as the pressure (P) is increased, from P = 0 GPa to P = 360 GPa at temperatures T, l decreases, E increases, r decreases, FeO₄ decreases and disappears, FeO₅ decreases, and FeO₆ increases at high P with P ≥ 150 GPa, FeO₅ disappeared at P ≥ 250 GPa and only FeO₆ appeared at T = 2300, 7000 K. In addition, when increasing T, P, the bond angle of Fe–O–Fe, O–Fe–O decreases, E increases, r decreases, l increases when T increases and l decreases when P increases, leading to the number of structural units FeO₄, FeO₅ increasing and FeO₆ decreasing when T increases and vice versa when P increases. In addition, the phase transition temperature (T_m), T_m = 2300 K was determined. All the obtained results will be the basis for future experimental studies of amorphous Fe₂O₃ materials.