In recent years, the cerium-based conversion coatings have been increasingly used as one of the more promising chromate coatings substitutes on aluminum alloys, as cerium compound do not pose environmental problems and the coatings provide an efficient corrosion protection close to that of chromium. The cerium-based layer was prepared from simple immersion of aluminium alloy sheets in a solution composed of a 4 - 8 g·L-1 Ce(NO3)3·6H2O; 30 - 50 ml·L-1 H2O2 (37 %) and 0.5 - 1,5 g·L-1 tannin at room temperature. After optimization of several parameters as deposition bath composition, immersion time, drying temperature and so on, the corrosion resistance was evaluated mainly by means of salt spray tests (SST). It was established that the thickness of cerium-containing coatings is about 280 - 320 nm.Keywords: Corrosion protection, conversion coatings, cerium-containing coatings, chromate-free passivation, rare earths
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