Corrosion of chromate conversion films on aluminium in electrically bonded interfaces

PurposeThe present study aims to investigate the corrosion and electrical properties of the chromate conversion coatings on aluminium alloy Type 6061 in electrically bonded interfaces.Design/methodology/approachTests were carried out to obtain the optimum conditions for chromate bath composition and immersion time for standard requirement provisions such as corrosion resistance in the salt‐spray test, electrical resistance and coating quality. The applied coatings were tested electrochemically in seawater and distilled water. The protection mechanism was evaluated from Tafel and cyclic polarisation curves in the said environments.FindingsThe evaluations showed that the passive film layer contained chromate with alumina formed on the substrate. The good performance of the conversion coating in terms of its corrosion and electrical conductivity was probably due to the characteristics of this protective film.Originality/valueThe paper presents findings on the corrosion of chromate conversion films on aluminium in electrically bonded interfaces.