Technically anodised coatings grow 1/3 out of the metal and 2/3 into the metal. As a result, the bond of the layer with the base material is extremely high. However, the growth behaviour must be considered in the design of the components with respect to fitting.
Due to different electrolytes and electrolyte parameters, anodically produced oxide layers have very varied properties and satisfy the most diverse requirements. The appearance, ie. colour and gloss, and the properties of the oxide layers, e.g. hardness, corrosion resistance and wear resistance, depend on the composition of the base material and above all on the alloying additions as well as on the surface treatment, the anodisation parameters and the layer thickness. Technically anodised coatings can also fulfil different decorative requirements. For these purposes, for example, pretreatments such as pickling, grinding, blasting or polishing are performed.
Technically anodised coatings are resistant to non-acidic and alkaline media. With appropriate layer thickness and compression, the layer even withstands acidic or weakly alkaline attacks for a short time. The hardness of the technically anodised layer is influenced by the composition of the material, in particular by the alloy constituents. The technically anodised coating significantly increases the wear resistance of the aluminium. However, highly wear-resistant surfaces are only produced by hard coating (see HART-COAT® process). The combination of PTFE with technical anodising coatings results in very good anti-friction properties for the coating.