T. Vilella et al. Engineering TNZT-coated titanium scaffolds via additive manufacturing and magnetron sputtering for bone tissue replacement. Surface and Coatings Technology

T. Vilella, E. J. Delgado-Pujol, C. García-Hernández, G. Fargas, C. R.M. Alfonso, D. Rodríguez, C. García-Cabezón, A. Alcudia, J. C. Sánchez-López, Y. Torres. Engineering TNZT-coated titanium scaffolds via additive manufacturing and magnetron sputtering for bone tissue replacement. Surface and Coatings Technology, Volume 522, 15 February 2026, 13312.

doi: doi.org/10.1016/j.surfcoat.2025.133128

Abstract

The biomechanical behavior and corrosion phenomena of porous metallic implants can compromise their clinical success. This work proposes modifying the surface of c.p. titanium scaffolds manufactured by 3D-printing (Direct Ink Writing), depositing a thin film of a β-Ti alloy (Ti-35Nb-7Zr-5Ta) using the High-Power Impulse Magnetron Sputtering (HiPIMS) technique. The versatility of this technique has enabled the fabrication of conformal coatings with uniform thickness, excellent adhesion, a nanorough surface, and a homogeneous columnar distribution. Regarding the biofunctional behavior of the coatings, contact angle measurements and a comprehensive electrochemical study (including impedance spectroscopy, open-circuit potential, and anodic polarization) were performed in artificial saliva. The results are discussed in terms of 1) the potential of the HiPIMS technique; and 2) the role of the coating (effect on stress shielding, improved corrosion resistance, and fatigue life potential). Electrochemical measurements demonstrate the effectiveness of the coating in improving corrosion resistance. In particular, the corrosion current density decreased from 1.62 ± 0.06 μA/cm2 for uncoated scaffolds to 0.31 ± 0.01 μA/cm2 after coating. At the same time, the polarization resistance increased nearly fivefold (from 0.84 × 105 to 3.72 × 105 Ω·cm2), confirming the protective effect of the TNZT film. The scaffold porosity favors bone ingrowth, while the reduced Young's modulus of the HiPIMS-deposited TNZT coating minimizes bone resorption. Moreover, its higher nanohardness suggests a potential increase in fatigue resistance. Finally, the synergistic combination of DIW-engineered porosity and a compact HiPIMS-deposited TNZT film will successfully alleviate stress shielding while enhancing corrosion resistance and biofunctional compatibility.