The mechanism of solution acidification during chemical conversion process on aluminium alloys

摘要

In this report, chromate-free conversion coating was produced on aluminium alloy by a solution containing cerium nitrate and potassium permanganate. The pH-potential diagram of cerium nitrate/potassium permanganate system was achieved. It was found that the oxidation of Ce3+ by MnO4- led to the solution acidification. The structure, composition and valence state of conversion coating were characterised. The mechanism of conversion coating formation on aluminium alloy in the solution containing cerium/potassium permanganate was studied.

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