Kinetic and crystallographic control of self-ordering of pores in anodic aluminium oxide

Electrochemical oxidation of aluminium in acidic electrolyte solutions, also known as anodizing, is a widely used process for the finishing of pure aluminium and its alloys. The resulting anodic aluminium oxide (AAO) porous films play a significant role in modern science and technology. One of the most exciting features of AAO is the self-organization of pores into two-dimensional hexagonal patterns under specific anodizing conditions. The combination of a hexagonal arrangement of pores and precise control over pore diameter, interpore distance, and film thickness gives rise to a wide range of potential applications from decorative coatings to quantum technologies. This review discusses the kinetic approach to the guided search for anodizing conditions that lead to the formation of highly ordered porous structures, as well as recent data on how the crystallographic orientation of the aluminium substrate affects the growth rate and structure of AAO.