In Situ Atomic-Scale Oscillation Sublimation of Magnesium under CO2 Conditions.

Understanding the interactive role between Mg and CO2 is crucial for many technological applications, including CO2 storage, melting protection, corrosion resistance, and ceramic welding. Here we report observations of rapid oscillation sublimation of Mg at room temperature in the presence of both CO2 gas and electron irradiation using environmental transmission electron microscopy. The sublimation is mainly related to phase transformation of amorphous MgCO3. Differing from the direct formation of gas-state MgCO3, which attributes to the sublimation of pure Mg under a mild electron beam dose, a unique oscillation process is detected during the process of Mg sublimation under a harsh electron beam dose. The main reason stems from the first-order reaction of a reversible decomposition-formation of amorphous MgCO3. These atomic-level results provide some interesting insights into the interactive role between Mg and CO2 under electron beam irradiation.