Effects of Zr Ion Implantation on Surface Mechanical Properties and Corrosion Resistance of Pure Magnesium
- PDF / 2,052,371 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 62 Downloads / 206 Views
ÓASM International 1059-9495/$19.00
Effects of Zr Ion Implantation on Surface Mechanical Properties and Corrosion Resistance of Pure Magnesium Zhixin Ba, Yongqiang Jia, Qiangsheng Dong, Zhuangzhuang Li, and Juan Kuang (Submitted September 19, 2018; in revised form April 10, 2019; published online April 24, 2019) Zirconium (Zr) was implanted into pure Mg by metal vapor vacuum arc (MEVVA) at the dose of 2 3 1016 ions/cm2 at room temperature. The surface characteristics of Zr-implanted Mg were analyzed by the Stopping and Range of Ions in Matter software (SRIM) and x-ray photoelectron spectroscopy (XPS), the surface nanohardness and tribological behavior were measured through nanoindentation and a frictionabrasion testing machine, and the corrosion resistance of Zr-implanted Mg was evaluated by electrochemical measurement and immersion test in simulated body fluid (SBF). The results demonstrated that a gradient modified layer composed of MgO, Mg(OH)2, ZrO2 and Zr was formed on the near surface of pure Mg and the nanohardness of pure Mg was improved by 48%. Furthermore, the Zr-implanted Mg exhibited a more positive corrosion potential of 2 1.43 V (versus SCE) and a lower corrosion current density of 19.9 lA/cm2, and localized corrosion was effectively retarded during 24 h immersion in SBF, suggesting that the corrosion resistance of pure Mg was remarkably improved after Zr ion implantation. The mechanisms of surface strengthening and improved corrosion resistance were also discussed in this paper. Keywords
corrosion resistance, magnesium, nanohardness, tribological behavior, zirconium ion implantation
1. Introduction Magnesium (Mg) and its alloys have been generally recognized as revolutionary materials in biomedical applications due to their outstanding biocompatibility and biodegradability, particularly as orthopedic implants in the human body (Ref 1-3). Magnesium could degrade spontaneously in the physiological system, which avoids the second surgery and alleviates surgery pain and economic burden to some extent. Furthermore, Mg and its alloys have suitable density, elastic modulus and yield strength similar to the human bone, which could avoid stress shielding effect and facilitate the healing of bone tissue. Besides, magnesium is an essential element in human metabolism, and the released Mg from implants degradation will be absorbed and participate in various biological reactions in the body (Ref 4, 5). However, the major obstacle of the extensive clinical application of Mg and its alloys is their rapid degradation rate in the physiological environment. The fast hydrogen gas evolution and local alkalization along with degradation would have a deleterious effect on tissue healing and human health (Ref 6). Also, the mechanical integrity of magnesium implants could lose and lead to incomplete tissue healing as well as the failure of surgery. It is generally known that Mg alloys have poor wear
Zhixin Ba, Yongqiang Jia, Qiangsheng Dong, Zhuangzhuang Li, and Juan Kuang, School of Materials Science and Engineering, Nanji
Data Loading...
