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Golden-yellow-colored cerium conversion coatings on AZ91D magnesium alloy were obtained by immersion in ethanol solution and post-treated in 3.0 wt.% Na(3)PO(4) aqueous solution. SEM revealed that the coatings deposited more heavily on alpha phase than on beta phase. XPS results showed that the coatings consist of CeO(2), Ce(2)O(3), CePO(4), Al(2)O(3), Mg(3)(PO(4))(2) and MgO. Corrosion tests indicated that the coatings with post-treatment significantly reduced the corrosion rate of AZ91D alloy in NaCl solution. The post-treatment is necessary for better corrosion resistance. The corrosion resistance of the coatings with post-treatment is superior to that of DOW No.1 coating. (C) 2009 Elsevier Ltd. All rights reserved.