Bio-Functional Coating on Ti6Al4V Surface Produced by Using Plasma Electrolytic Oxidation

• Published in: Metals (Basel ) Vol. 10; no. 9; p. 1124
• Main Authors: Zakaria, Aqmar, Shukor, Hamdi, Todoh, Masahiro, Jusoff, Kamaruzaman
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2020
• Subjects: Adhesion tests; Adhesive strength; Anatase; bioactive coating; Biological activity; Biomedical materials; Body fluids; Calcium fluoride; Calcium phosphates; Chemical composition; Corrosion resistance; Dental implants; Electrolytes; Failure rates; Field emission microscopy; Fluorapatite; Fluorides; Hydroxyapatite; In vitro methods and tests; Morphology; Open source software; Orthopedics; Oxidation; Phase composition; plasma electrolytic oxidation; Potash; Potassium; Potassium hydroxides; Power supply; Protective coatings; Scratch tests; Slaked lime; Surgical implants; Ti6Al4V; Titanium; Titanium base alloys; Titanium dioxide; United States > US; Japan
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met10091124

One way to improve the biofunctionality of titanium alloys is by implementing plasma electrolytic oxidation (PEO) to incorporate bioactive elements such as fluoridated hydroxyapatite, into surface coatings of orthopaedic and dental implants. Hydroxyapatite (HAp) is known as a bioactive coating while fluorapatite (FAp) has an antibacterial effect that would enhance the bio-functionality and reduce the failure rate of orthopaedic and dental implants. The purpose of this study was to develop fluoridated hydroxyapatite as a bio-functional coating on Ti6Al4V with electrolyte containing trisodium orthophosphate, potassium hydroxide, and calcium fluoride. The coating surface and cross-section morphologies were evaluated, and the species in the electrolyte solution were found, and irregular micropores shapes were observed by field emission scanning electron microscopy (FESEM) and energy dispersive spectrometer (EDS). The phase composition of the coating surface containing TiO2 (anatase and rutile), tricalcium orthophosphate, HAp, and FAp was characterized by X-ray diffractometer (XRD). The adhesive strength of the coating was analysed by a micro-scratch test. Simulated body fluid (SBF) immersion test was performed to investigate the bioactivity of the coating. In this study, we demonstrated that the PEO technique has a good potential to develop bio-functional surface modifications that can affect the chemical composition and roughness of the coating surface. The FAp coating may provide insights for subsequent bioactive coatings while improving the antibacterial properties for orthopaedic and dental implants. Future work shall investigate the optimal amount of fluoride in the coating layer that obtains excellent results without causing adverse effects on adjacent tissue.