Surface Modification of Magnesium and its Alloys Using Anodization for Orthopedic Implant Application

Abstract

Magnesium (Mg) as a biodegradable implant brings a revolution in medical field application, especially in bone implant and stent application. Biodegradability of Mg has attracted attentions of researchers to avoid secondary surgery to remove the implant materials after healing process. Various advantages of Mg make it suitable for medical application such as density, good mechanical properties and biodegradation. However, Mg biodegradability must be controlled to meet tissue-healing period of time because of the high degradation in a physiological environment. Fast corrosion and high alkalinity due to hydrogen release induce tissue inflammation, which limits its clinical applications. Many techniques are applied to the Mg surface to improve surface biocompatibility and control its biodegradability. This chapter focuses on anodization of Mg and its alloys to improve corrosion resistance and biocompatibility for orthopedic application. Mg coating with thin film apatite could enhance the biocompatibility and increase osseointegration formation in the bone fracture side. Evaluation of the required anodized film discussed in the chapter such as chemical composition, biodegradability and biocompatibility.

The effect of anodizing electrolyte composition on electrochemical properties of anodized magnesium

“…In some surface treatments, despite the thick coating film, they have low corrosion resistance, which shows the corrosion resistance depends on the density and composition of the coating more than the thickness of the coating (Darband et al, 2017;Echeverry-Rendon et al, 2018;Fattah-alhosseini et al, 2020;Mousa et al, 2017;Song et al, 2019). Baghdadabad et al in a study using plasma electrolytic oxidation process achieved a coating with an average thickness of 3.5 mm and corrosion resistance of about 230,000 ohms (Baghdadabad et al, 2020), while in the present study, the thickness of 11 mm and corrosion resistance of almost 2700 ohms was obtained.…”

Applications of Magnesium and Its Alloys: A Review

“…Presently, alloying, by itself, seems to be limited in clinical practice as its ability to improve corrosion resistance is insignificant [65]. However, modifying the surface with a coating layer effectively controls the initial degradation of magnesium and its alloys [66]. Compared to alloying, surface modification can retain the material's critical properties while achieving enhanced corrosion resistance and biocompatibility [67].…”

“…The main types of coating include polymeric coatings, calcium-phosphate coatings, and graphene coatings [46]. For an in-depth discussion on surface modifications for magnesium and its alloys, one can refer to publications by Mousa et al [66] and Zeng et al [62].…”

Applications of Magnesium and its Alloys: A Review

“…Presently, alloying, by itself, seems to be limited in clinical practice as its ability to improve corrosion resistance is insignificant [37]. On the other hand, modifying the surface with a coating layer effectively controls the initial degradation of magnesium and its alloys [38]. Compared to alloying, surface modification can retain the material's critical properties while achieving enhanced corrosion resistance and biocompatibility [39].…”

“…The main types of coating include polymeric coatings, calcium-phosphate coatings, and graphene coatings [24]. For an in-depth discussion on surface modifications for magnesium and its alloys, one can refer to publications by Mousa et al [38] and Zeng et al [35].…”