Molecular dynamics investigation of the thermal behaviors of magnesium oxide ceramics at different pressures and temperatures.

Abstract

Today, magnesia ceramics have attracted considerable attention due to their essential properties. Therefore, this paper investigates the impact of temperature (T) and pressure (P) on the thermal manner of magnesia ceramics using molecular dynamics simulations (MDS). As the T increases, the mobility of the structures increases. Therefore, the heat flux (HF) in the structures increments slightly due to the greater movement and the larger oscillation amplitude of the atomic samples. On the other hand, with increasing P, the oscillation amplitude and displacement of atomic samples are limited. Therefore, the thermal properties of the structure are expected to decrease. Studies show that increasing T from 250 to 350K increases the average HF from 0.73 to 0.89W/m2. Also, the average thermal conductivity (TC) increases from 30.58 to 38.27W/mK. So, increasing the T means a certain amount of energy is fluxed in a shorter time. On the other hand, increasing the P from 0 to 5bar decreases the average HF from 0.82 to 0.65W/m2. Also, this issue leads to a decrease in the average TC from 33.49 to 30.96W/mK.