Beschreibung Nowadays most aeronautical parts made of aluminium alloys are protected against corrosion by surface anodising and multilayer painting. The treatment is usually carried out with Cr(VI) based compounds. However Cr(VI) substances are affected by REACh regulation and the European Commission will set more and more restriction for their use from 2024 onwards. To date, there is not any Cr(VI)-free protecting treatment for Aluminium 7000 series alloys that match the results obtained with the Cr(VI) based coatings, so, it is necessary to develop an environmentally and Cr(VI)-free acceptable alternative process.