Corrosion resistance and antibacterial properties of TiAl6Nb7 alloys coated with a zinc-doped calcium phosphate layer

Date

2026-01-01

Author

Pana, Iulian
Parau, Anca C.
Dinu, Mihaela
Vitelaru, Catalin
Büyüksungur, Senem
Endoğan Tanır, Tuğba
Vranceanu, Diana Maria
Schmidt, Jürgen
Vladescu (Dragomir), Alina
Hasırcı, Nesrin

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Zinc-doped calcium phosphate (CaP/Zn) coatings were deposited on TiAl6Nb7 alloy to improve corrosion protection while imparting antibacterial functionality for implant applications. CaP electrolytes containing Zn precursors were used to obtain porous Zn-doped CaP layers via micro-arc oxidation (MAO). Surface morphology and chemistry were assessed by SEM/EDS and ATR–FTIR, while topography, mechanical response, adhesion, wettability, and corrosion behavior were evaluated by surface profilometry, nanoindentation, scratch testing, contact angle/surface free energy measurements, and electrochemical tests in simulated body fluid (SBF, 37 °C), including OCP, Tafel polarization, and EIS. FTIR spectra confirmed phosphate- and hydroxyl-related bands characteristic of apatite-like CaP phases, and SEM revealed a porous morphology with reduced cracking and smaller voids at higher Zn levels. Corrosion testing showed a substantial improvement for Zn-doped CaP coatings compared with the uncoated alloy, with the Zn50 process condition providing the lowest corrosion current density (0.333 μA cm−2) and the highest polarization resistance. Nanoindentation indicated lower H and E for the coatings than for the substrate, with a non-monotonic dependence on Zn content. In vitro assays with Saos2 cells and indirect cytotoxicity tests with L929 extracts exhibited high cell viability and no cytotoxicity across all coatings. Antibacterial tests demonstrated the highest antibacterial efficacy against E.coli for the CaP/Zn100 sample with minimal bacterial attachment on the surface. Overall, MAO-derived Zn-doped CaP coatings provide a promising multifunctional surface modification strategy for TiAl6Nb7 implants. Among the investigated coatings, Zn50 exhibited the best overall balance between corrosion protection and cytocompatibility, whereas Zn75 promoted biomineralization and Zn100 provided the highest antibacterial activity.

Subject Keywords

Antibacterial efficacy, Corrosion resistance, Saos2 cells, Tafel Polarization, TiAl6Nb7alloy, Zinc-doped calcium phosphate

URI

https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=105046180968&origin=inward
https://hdl.handle.net/11511/120335

Collections

Biomaterials and Tissue Engineering Application and Research Center (BİOMATEN), Article