Multifunctionality of Y2O3 sol–gel coatings deposited on 316L stainless steel during exposure to Ringer’s and SBF solutions

• The modification of the composition of the coating solution containing Y 2 O 3 was evaluated. • Y 2 O 3 coatings are characterized by a tendency to accumulate yttrium on the surface. • The change in the roughness of the steel affect the deposition of apatite ceramics on the layers. • The concentration of the precursor influences the production of coatings with high corrosion resistance. • Coatings with a sol concentration of 1:50 have the best barrier properties in the Ringer environment. Modern medicine places increasing demands on materials used for implants. Such materials, despite their high biocompatibility and corrosion resistance in the environment of body fluids, should also support tissue regeneration. The paper presents the properties of Y 2 O 3 ceramic coatings obtained by the sol–gel method at three different precursor concentrations. The morphology on both the surface and the cross-section (SEM/FIB), long-term corrosion resistance in the Ringer solution (dc and ac methods) and the growth of apatite ceramics in the SBF solution (ICP-OES) were characterized. The best synergy between barrier properties and the growth of apatite ceramics was characterized by the 1:50-316L sample. SEM analyses showed that Y 2 O 3 aggregates on the surface, creating areas of greater thickness (500–700 nm) separated by a coating of the order of (20–40 nm) thickness. The 1:50-316L sample was characterized by the highest polarization resistance after 60 days of exposure in Ringer’s solution (Rp = 1.35 MΩ cm 2 ). The EIS technique confirmed the best barrier properties of the 1:50-316L sample. Apatite ceramics grew after 60 days of exposure in the SBF solution. The multifunctionality of Y 2 O 3 coatings is based on the combination of a barrier effect with an effect supporting the growth of apatite ceramics.