Synthesis and characterization of strontium‐fluoride co‐substituted hydroxyapatite coating

Abstract The common method to regulate the bonding strength of hydroxyapatite (HAp) coating and metal substrate by adding low‐expansion additives usually sacrifices the biological properties of the coating. To avoid the adverse effects of external additives, HAp coating modified by in situ co‐substitution with strontium (Sr) and fluoride (F) ions was prepared on the surface of titanium substrates by electrochemical deposition method. The effects of Sr substitution and F substitution on the coating's morphology, hydrophilicity, electrochemical behavior, in vitro bioactivity, biocompatibility, and bonding strength were investigated. Increased Sr substitution promoted bioactivity, while F substitution induced more regular structure and improved electrochemical behavior. All coating samples were hydrophilic and biocompatible. Sr‐F co‐substituted HAp coating could improve the bonding strength between the coating and substrates and enhance comprehensive biological properties.