Micro-Arc Oxidation in Titanium and Its Alloys: Development and Potential of Implants

Abstract

Titanium (Ti) and its alloys are widely recognized as preferred materials for bone implants due to their superior mechanical properties. However, their natural surface bio-inertness can hinder effective tissue integration. To address this challenge, micro-arc oxidation (MAO) has emerged as an innovative electrochemical surface modification technique. Its benefits range from operational simplicity and cost-effectiveness to environmental compatibility and scalability. Furthermore, the distinctive MAO process yields a porous topography that bestows versatile functionalities for biological applications, encompassing osteogenesis, antibacterial, and anti-inflammatory properties. In this review, we undertake an examination of the underlying mechanism governing the MAO process, scrutinize the multifaceted influence of various factors on coating performance, conduct an extensive analysis of the development of diverse biological functionalities conferred by MAO coatings, and discuss the practical application of MAO in implants. Finally, we provide insights into the limitations and potential pathways for further development of this technology in the field of bone implantation.

Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview

“…The performance of titanium implants was previously investigated with incorporated magnesium in vivo [ 298 , 299 ]. Using micro-arc oxidation, titanium surfaces with magnesium incorporation were generated and significant enhancements in osseointegration were observed, despite minimal changes in topographical parameters [ 300 , 301 ]. The magnesium-modified implants demonstrated increased resistance to removal from bone and exhibited greater bone-to-implant contact [ 302 , 303 ].…”

Mutual Impact of Four Organic Calcium Salts on the Formation and Properties of Micro-Arc Oxidation Coatings on AZ31B Magnesium Alloys

“…Generally, a higher concentration of the electrolytes in an MAO solution suggests a higher ionic strength of the solution and a higher electronic field strength under a constant current mode, which helps to achieve lower breakdown voltage and thus more efficient deposition and be er corrosion resistance in an MAO coating [1,3,18]. However, too high an electronic field strength and energy would promote intensive, large-sized and unevenly distributed spark discharges on the sample surface, resulting in increased reaction intensity, the formation of MAO coatings with large micropores, and even the localized ablation of the coating [1,3,18,23,32,47,48]. In this study, coating ablation microbumps appeared on samples No.…”

“…10.04CaLac2 (Figures 2c,g, 8a2,a3, 9e1 and 10e1), all of which were prepared in the solutions with higher [Ca 2+ ]T, accompanied by more violent spark discharging and a higher final voltage of over 480 V. To be precise, as shown in Tables 1 and 2 Generally, a higher concentration of the electrolytes in an MAO solution suggests a higher ionic strength of the solution and a higher electronic field strength under a constant current mode, which helps to achieve lower breakdown voltage and thus more efficient deposition and better corrosion resistance in an MAO coating [1,3,18]. However, too high an electronic field strength and energy would promote intensive, large-sized and unevenly distributed spark discharges on the sample surface, resulting in increased reaction intensity, the formation of MAO coatings with large micropores, and even the localized ablation of the coating [1,3,18,23,32,47,48]. In this study, coating ablation microbumps appeared on samples No.…”

“…Various surface modification and coating techniques have been applied to suppress the degradation of Mg alloys or even to endow them with improved cytocompatibility [1][2][3][4][5][6][7][8], osteogenesis ability [1][2][3][4][5][6], antibacterial ability [1][2][3][4][5][6], and antitumor ability [7,8]. Among these, micro-arc oxidation (MAO) has received considerable attention, since MAO coatings are generated via in situ oxidation and sintering on magnesium alloys [1,3,4,9], aluminum alloys [10][11][12][13], titanium alloys [14][15][16][17][18], and tantalum alloys [19], and therefore exhibit high hardness, good wear resistance, and corrosion resistance. Most importantly, the composition, structure, papers from 80 to 3000 grits, cleaned with tap and distilled water, and finally dried in an air stream.…”

Titanium Nitride Coatings on CoCrMo and Ti6Al4V Alloys: Effects on Wear and Ion Release

“…In response to recent findings, our study has incorporated advanced physical vapor deposition (PVD) techniques, specifically arc evaporation (Arc) and high-power impulse magnetron sputtering (HiPIMS), to enhance the quality of coatings in orthopedic implants. Arc technology, known for producing robust and adherent coatings, often necessitates post-treatment due to microdroplet-induced roughness, a challenge acknowledged in prior studies [16,17]. This post-treatment is crucial to rectify the significant defects and high defect density observed in TiN coatings applied via Arc technology, especially as seen in the retrieval analysis of coated prosthetic femoral heads [16].…”