Marcela Trybula1 2 Przemyslaw Szafranski3 Pavel Korzhavyi2 4 Nikolay Vinogradov5 Edvin Lundgren6

1, Institute of Metallurgy and Materials Science Polish Academy of Sciences, Krakow, , Poland
2, Department of Materials Science and Engineering, KTH-Royal Institute of Technology, Stockholm, , Sweden
3, Department of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, , Poland
4, Institute of Metal Physics, Ural Branch of RAS, Ekaterinburg, , Russian Federation
5, MAX IV Laboratory, Lund University, Lund, , Sweden
6, Synchrotron Radiation Research, Lund University, Lund, , Sweden

Structural disorder in amorphous solids may depend on the method of their preparation. An easily-accessible method is electrochemical anodization of metal surface, which may result in formation of periodic voids, or pores, for example in a well-known Al anodization process [1,2]. These voids, or pores, are thought to derive from the morphological instabilities underlying the initial stage of oxidation [1]. Such nanostructuring can have a profound impact on local structural anisotropy or hierarchical ordering of atom clusters build-up in the structure of the amorphous Al oxide film.

In this contribution, we determine the structural and topological descriptors of bulk alumina to compare them with those obtained from in situ synchrotron-based experiment of porous anodic aluminum oxide scale growth. We also discuss the impact of self-assembling ring structure on chemical and topological short- and intermediate-range ordering in bulk alumina in the light of in situ oxide growth. The interpretation of our in situ X-ray diffraction data is supported by molecular dynamics simulations and DFT-based calculations. These allowed us to capture physical phenomena accompanying in situ anodic aluminum oxide growth. Obtained calculation results agree well with the available experimental [3] and computational data [4].

[1] K. R. Hebert, et al.: Nat. Mater. 2011, 11, 162−166.
[2] N. A. Vinogradov et al.; ACS Appl. Nano Mater. 2018, 1, 1265-1271
[3] P. Lamparter and R. Knieb Physica B 1997, 234-236, 405-406.
[4] G. Gutierrez and Borje Johansson, Phys. Rev. B 65, 104202:1-9