In Situ TEM Observation of Phase Transformation Nucleation at the Near-Surface of Synthetic Aragonite

Electron beam irradiation is well known to induce damage to materials during transmission electron microscope (TEM) characterization, especially for insulating materials. Phase transformation is an important damage phenomenon caused by beam irradiation. Here, we employed in situ TEM combined with electron-energy loss spectroscopy (EELS) to dynamically track the phase transformation of synthetic aragonite. The evolution process and underlying mechanism of the phase transformation in aragonite are systematically discussed. This work reveals that the near-surface region of aragonite undergoes a phase transformation induced by electron beam irradiation, prior to the bulk of aragonite. It provides more possibilities for searching the multiple near-surface properties of materials.