The data set consist in 4 compressed folders: one is the Fiji script (ESEM movie maker) used in my thesis to obtain video from ESEM images and three are python notebooks (Data extraction and synchronization, Hyperspy EDS Analysis, Diffusion simulation) also used in my thesis. Data are also provided to test the script and notebooks. Appendix F and G from the thesis can also be downloaded here. Appendix F (User guide of the Fiji script): guidelines for using the script written for post-acquisition processing of environmental scanning electron microscopy images. Appendix G(User guide of python notebook): guidelines for using the python notebook to display interactively mass spectrometer signals. Notebook 1 (Data extraction and synchronization): Processing the EDX data from STEM and SEM thanks to the Hyperspy library. Notebook 2 (Hyperspy EDS Analysis): processing the MS data in order to allow a clear visualisation and an easier interpretation thanks to interactive plots using the Bokeh library. Notebook 3 (Diffusion simulation): Simulating the interdiffusion between cobalt and iron thanks to the Pydiffusion library.

Acknowledgements for funding: The Max Planck -EPFL center for initiating the collabora-tion and financing the first half of the thesis). The SwissNational Fund for funding the second half of the thesis un-der the AWESOME (Analysis of Solid Oxide Material closeto Working conditions by Environmental Scanning ElectronMicroscopy) project, grant number: 200021 176025.