中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 17 Special 1 November 2007 |
AZ91HP magnesium alloy
(1. Jiangxi Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University,
Nanchang 330013, China;
2. Jinhua College of Profession and Technology, Jinhua 321007, China;
3. College of Material Science and Engineering, Jiangxi Science and Technology Normal University,
Nanchang 330013, China)
Abstract:In a basic solution containing 10 g/L NaOH, the thickness, morphology and corrosion resistance of anodic coatings formed in solutions without and with additions of Na2SiO3, Na2CO3, Na2B4O7 and Na2SnO3 were separately determined and evaluated. The results show that the electrolytes used above take part in the coating formation and the obtained anodic coatings contain elements from the electrolytes. These electrolytes, especially Na2SiO3 and Na2B4O7, contribute to the film thickness. The coating uniformity obtained by addition of Na2SiO3 is the best, while Na2CO3, Na2B4O7 and Na2SnO3 decrease the number of pores per area on the coatings surface though they worsen the uniformity of the anodic coatings. In addition, the anodic coatings formed in solutions with addition of Na2CO3 or Na2SnO3 exhibit loose and net-like structure. Na2SiO3 and Na2B4O7 can significantly improve the corrosion resistance of the anodic coatings while Na2CO3 and Na2SnO3 have minor effects on improving the coating corrosion resistance.
Key words: magnesium alloy; anodic coatings; electrolyte; effect