Bio-Medical Materials and Engineering 27 (2016) 287–303 287 DOI 10.3233/BME-161585 IOS Press Topography, wetting, and corrosion responses of electrodeposited hydroxyapatite and fluoridated hydroxyapatite on magnesium Mahtab Assadian a , Hassan Jafari b,∗ , Seyed Morteza Ghaffari Shahri a , Mohd Hasbullah Idris a and Davood Almasi a a Departments of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, UTMSkudai, 81310, Johor, Malaysia b Department of Materials Engineering, Faculty of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, 16785-136, Iran Received 17 December 2015 Accepted 1 July 2016 Abstract. In this study, different types of calcium-phosphate phases were coated on NaOH pre-treated pure magnesium. The coating was applied by electrodeposition method in order to provide higher corrosion resistance and improve biocompatibility for magnesium. Thickness, surface morphology and topography of the coatings were analyzed using optical, scanning electron and atomic-force microscopies, respectively. Composition and chemical bonding, crystalline structures and wettability of the coatings were characterized using energy-dispersive and attenuated total reflectance–Fourier transform infrared spectroscopies, grazing incidence X-ray diffraction and contact angle measurement, respectively. Degradation behavior of the coated speci- mens was also investigated by potentiodynamic polarization and immersion tests. The experiments proved the presence of a porous coating dominated by dicalcium-phosphate dehydrate on the specimens. It was also verified that the developed hydroxy- apatite was crystallized by alkali post-treatment. Addition of supplemental fluoride to the coating electrolyte resulted in stable and highly crystallized structures of fluoridated hydroxyapatite. The coatings were found effective to improve biocompatibility combined with corrosion resistance of the specimens. Noticeably, the fluoride supplemented layer was efficient in lowering cor- rosion rate and increasing surface roughness of the specimens compared to hydroxyapatite and dicalcium-phosphate dehydrates layers. Keywords: Magnesium, biodegradable implant, fluoridated hydroxyapatite, electrodeposition, corrosion 1. Introduction The first trials of utilizing magnesium and its alloys as a biomaterial in orthopaedic and vascular ap- plications took place in the late 1800s [1]. Thanks to the similar mechanical properties of magnesium * Corresponding author: Hassan Jafari, Department of Materials Engineering, Faculty of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, 16785-136, Iran. Tel.: +989120927517; Fax: +982122970022; E-mails: jafari_h@yahoo.com, hjafari@srttu.edu. 0959-2989/16/$35.00 © 2016 – IOS Press and the authors. All rights reserved