Functional bioactive glass topcoats on hydroxyapatite coatings: Analysis of microstructure and in-vitro bioactivity

International audienceA bioactive glass topcoatwas introduced to modify the surface morphology and in-vitro reactivity of hydroxyapatite(HA) coatings for biomedical applications. With this aim, a CaO-rich bioactive glass, termed BG_Ca (wt.%: 4.7Na2O, 42.3 CaO, 6.1 P2O5, and 46.9 SiO2),was selected due to its good bioactivity and lowtendency to crystallize athigh temperature. The standardHA coatings were sprayed through atmospheric plasmaspray (APS) on steel substratesstarting from commercial powders (“APS-HA” samples). The HA coatings, in turn, were subsequentlycoated with a thin layer of bioactive glass by suspension plasma spray (SPS), thus obtaining the duplex systems(“APS-HA/SPS-BG_Ca” samples). The samples with andwithout the BG_Ca layer were analysed by microstructuralcharacterization and by in vitro tests in simulated body fluid (SBF). The analysis revealed an increased reactivityof the APS-HA/SPS-BG_Ca samples compared to the glass-free APS-HA coatings.© 2013 Elsevie