Corrosion mechanism of micro-arc oxidation treated biocompatible AZ31 magnesium alloy in simulated body fluid

• Published in: Progress in natural science Vol. 24; no. 5; pp. 516 - 522
• Main Authors: Li, Ying, Lu, Fang, Li, Honglong, Zhu, Wenjun, Pan, Haobo, Tan, Guoxin, Lao, Yonghua, Ning, Chengyun, Ni, Guoxin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2014; School of Materials Science and Engineering, South China University of Technology, Guangzhou, China%Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China%Center for Human Tissues and 0rgans Degeneration, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen, China%Institute of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, China%Department of 0rthopeadics and Traumatology, Nanfang Hospital, Southern Medical University, China
• Subjects: alloy; AZ31; AZ31 magnesium alloy; Biodegradable; Corrosion; Corrosion resistance; magnesium; Mechanism; Micro-arc; Micro-arc oxidation; oxidation; resistance; Corrosion resistance; Biodegradable; AZ31 magnesium alloy; Mechanism; Micro-arc oxidation
• DOI: 10.1016/j.pnsc.2014.08.007
• ISSN: 1002-0071

The rapid degradation of magnesium(Mg) based alloys has prevented their further use in orthopedic trauma fixation and vascular intervention,and therefore it is essential to investigate the corrosion mechanism for improving the corrosion resistance of these alloys. In this work, the effect of applied voltage on the surface morphology and the corrosion behavior of micro-arc oxidation(MAO) with different voltages were carried out to obtain biocompatible ceramic coatings on AZ31 Mg alloy. The effects of applied voltage on the surface morphology and the corrosion behavior of MAO samples in the simulated body fluid(SBF) were studied systematically. Scanning electron microscope(SEM) and X-ray diffractometer(XRD)were employed to characterize the morphologies and phase compositions of coating before and after corrosion. The results showed that corrosion resistance of the MAO coating obtained at 250 V was better than the others in SBF. The dense layer of MAO coating and the corrosion precipitation were the key factors for corrosion behavior. The corrosion of precipitation Mg(OH)2and the calcium phosphate(Ca–P) minerals on the surface of MAO coatings could enhance their corrosion resistance effectively. In addition, the mechanism of MAO coated Mg alloys was proposed.