Hydroxyapatite Composite Coatings On Titanium Surface By Electrochemical Deposition

Hydroxyapatite has a chemical composition and structure similar to human bone,and has the function of guiding bone tissue regeneration.Therefore,it is used as an implant surface coating to improve the biological inertness of pure titanium implant materials in the medical field.The preparation of hydroxyapatite coating with better performance is of great significance for its commercial application.In this paper,hydroxyapatite coating was prepared on titanium substrate by electrochemical method,and its application performance was improved by doping.1.The hydroxyapatite coating and the graphene oxide/hydroxyapatite coating were prepared on the surface of the titanium substrate by electrochemical deposition,and the coatings showed a rod-shaped porous structure.The experimental results showed that the crystallinity of HA in the coatings was continuously facilitated,with the increasing amount of GO in the obtained coatings.This demonstrated that GO was as the crystal nucleus in deposition of hydroxyapatite.As a support material,GO also improved the mechanical properties of hydroxyapatite.So that hydroxyapatite coating can bear more applications.2.For 3D printing of Titanium,constant current method was also an effective method to fabricate hydroxyapatite coatings.By two steps electrochemical depositions,the uniform hydroxyapatite coatings was also fabricated on 3D printing of titanium.And The color of the coating also changed with the addition of graphene oxide.As the current density increases,the microstructure of the coating also changed.This is due to the overgrowth of hydroxyapatite crystals.It is also found that hydroxyapatite has strong fluorescence by Raman spectra.3.GO/Magnesium doped hydroxyapatite coatings were fabricated by constant voltage method.With the increasing amount of Magnesium,so that make the chemical composition of hydroxyapatite coating closer to natural hydroxyapatite.Mg²⁺gradually replaced the Ca²⁺element in hydroxyapatite crystals and made the size of crystals become smaller.Mg²⁺also decreased the crystallinity mainly by inhibiting the growth of hydroxyapatite crystals during the whole deposition process.The hardness and elastic modulus of hydroxyapatite were also decreased.