THE CORROSION PROTECTION OF A MODIFIED CERIUM CONVERSION COATING FORMED ON ZINC

摘要

A modified cerium conversion film was obtained on surface of zinc by chemical conversion process. Influence of the additives in treating solution containing cerium salt on the corrosion protection of cerium conversion film formed on zinc was investigated. Corrosion tests and electrochemical measurements were performed The microstructure and composition of the coatings were examined by means of SEM, EDAX and XRD. It was found that the corrosion protection capabilities of cerium conversion film are markedly increased with the cerium salt plus additives HF and an organic inhibitor treating process. The modified cerium conversion film is an organic/inorganic composite coating and is more corrosion resistant than conventional chromate conversion coatings.