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

Abstract

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 (Tm), Tm = 2300 K was determined. All the obtained results will be the basis for future experimental studies of amorphous Fe2O3 materials.