Model of Structure of Al₂O₃ Layer Obtained Via Hard Anodising Method

Abstract

In the present paper, a model has been developed for the structure of an oxide layer obtained on aluminium as a result of the hard anodising process, which is widely used in industry. As a result of such processing, oxide layers with thicknesses within the range 30–100 µm (under certain conditions even up to 250 µm) can be obtained. It is worth noting that the oxide coatings obtained by this method on aluminium exhibit only a small level of porosity and have a high hardness. According to the method proposed, oxidation is carried out in a ternary water electrolyte called SAS, which contains sulphuric acid, adipic acid, and oxalic acid.