title: Investigation of the inner corrosion layer formed in pulse electrodeposition coating on Mg-Sr alloy and corresponding degradation behavior.
abstract: Magnesium-based metals are considered as promising biodegradable orthopedic implant materials due to their potentials of enhancing bone healing and reconstruction, and in vivo absorbable characteristic without second operation for removal. However, the rapid corrosion has limited their clinical applications. Ca-P coating by electrodeposition has been supposed to be effective to control the degradation rate and enhance the bioactivity. In this work, a brushite coating was fabricated on the Mg-Sr alloy by pulse electrodeposition (PED) to evaluate its efficacy for orthopedic application. Interestingly, an inner corrosion layer was observed between the PED coating and the alloy substrate. Meanwhile the results of in vitro immersion and electrochemical tests showed that the corrosion resistance of the coated alloy was undermined in comparison with the uncoated alloy. It was deduced that the existence of this corrosion layer was attributed to the worse corrosion performance of the alloy. The mechanism on formation of the inner corrosion layer and its influence on consequent degradation were analyzed. It can be concluded that the electrodeposition coating should be not suitable for those magnesium alloys with poor corrosion resistance such as the Mg-Sr alloy. More importantly, it should be noted that the process of coating formation combined with the nature of substrate alloy is important to evaluate the efficacy of coating for biodegradable Mg-based implants application.
authors.affiliation: Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Shangguan
authors.affiliation: Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China; Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region. Electronic address: pwan@imr.ac.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Wan
authors.affiliation: Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Tan
authors.affiliation: Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Xinmin
authors.initials: X
authors.lastname: Fan
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Ling
authors.initials: L
authors.lastname: Qin
authors.affiliation: Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China. Electronic address: kyang@imr.ac.cn.
authors.forename: Ke
authors.initials: K
authors.lastname: Yang
mesh_terms: D000497:Alloys / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004595:Electroplating; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C573915:Mg-Sr alloy
keywords: Coating; Degradation; Electrodeposition; Magnesium; Strontium