Production of bioactive hydroxyapatite coating by coblast process for orthopedic implants

Bioactive coatings composed of hydroxyapatite were successfully developed on AISI 316L substrate through a facile Coblast production technique. It was produced three different coatings using hydroxyapatite and two different abrasives (MCD and Al2O3). The topographical, morphological and chemical characteristics of the obtained coatings were performed using SEM, EDS and XRD analysis. The results revealed that all the produce coatings (Hap, Hap/MCD and Hap/Al2O3) showed a thickness of about 10 microns and a homogenous coverage of the substrate surface. The coatings were also subjected to a degradation test in simulated body fluid (SBF). The coatings biocompatibility evaluation after 13 days of immersion in SBF reveals for all the coatings an increase of OCP value, except for the Hap/Al₂O₃ coating. It was observed a decrease in passivation current density for the Hap/MCD coating after 13 days of immersion in SBF that can be assigned to the formation of a protective apatitic layer.