Raman investigation of an Fe(II)-containing solution influencing chromium chemistry in a thin film on aluminium

A modified trivalent chromium conversion coating formed in an Fe(II)-containing solution has been investigated by Raman spectroscopy. Fe(II)-containing salts revealed a promising additive to solve the presence of chromate constituent in a trivalent chromium conversion coating. However, the chloride solution can induce the chromate generation in such modified coating due to the presence of the dissolved oxygen in the solution.