Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Influence of Post-Annealing on the Oxide Layer of AZ91 Mg Alloy Prepared by Plasma Electrolytic Oxidation
Duck Young HwangYoung Gun KoYong Min KimBongyoung YooDong Hyuk Shin
Author information

2010 Volume 51 Issue 2 Pages 408-412


The influence of the post-annealing (PA) treatment on plasma electrolytic oxidation (PEO) treated AZ91 Mg alloy was investigated and the dependence of the dehydration reaction on the PA temperature was also studied. In this study, a series of PA treatments were carried out on the coated samples at four different temperatures, i.e. 373, 423, 473, and 523 K for 10 h. In contrast to the sample without PA treatment, the samples annealed at temperatures higher than 423 K exhibited a significant difference in terms of surface morphology since the MgO content in the oxide layer increased with increasing PA temperature. With increasing PA temperature, the dehydration of Mg(OH)2 led to the increase in the relative amount of the MgO, which was a hard phase. From the nano-indentation results, the applied loads of the samples were seen to increase as PA temperatures increased. Moreover, the corrosion resistance of the sample annealed at 423 K was higher than that of the samples annealed at three different PA temperatures.

Information related to the author
© 2010 The Japan Institute of Metals and Materials
Previous article Next article