Abstract
A family of TiHfZrNb high-entropy alloys has been considered novel biomaterials for high-performance, small-sized implants. The present work evaluates the role of niobium on passivation kinetics and electrochemical characteristics of passive film on TiHfZrNb alloys formed in Hanks’ simulated body fluid by analyzing electrochemical data with three analytical models. Results confirm that higher niobium content in the alloys reinforces the compactness of the passive film by favoring the dominance of film formation and thickening mechanism over the dissolution mechanism. Higher niobium content enhances the passivation kinetics to rapidly form the first layer, and total surface coverage reinforces the capacitive-resistant behavior of the film by enrichment with niobium oxides and reduces the point defect density and their mobility across the film, lowering pitting initiation susceptibility. With the high resistance to dissolution and rapid repassivation ability in the aggressive Hanks’ simulated body fluid, the TiHfZrNb alloys confirm their great potential as new materials for biomedical implants and warrant further biocompatibility testing.
Original language | English |
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Article number | 305 |
Journal | Journal of Functional Biomaterials |
Volume | 15 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2024 |
Externally published | Yes |
Funding
This research was funded by the Natural Sciences and Engineering Research Council of Canada through the Discovery Grant (RGPIN-2023-03884) and the Alliance International Catalyst Grant (ALLRP 571273-2021, ALLRP-585698-2023) (A.T., H.H.), and supported by the National Science Foundation (DMR 1611180, 1809640, and 2226508), the US Army Research Office (FA9550-23-1-0503, W911NF-13-1-0438, and W911NF-19-2-0049), the State of Tennessee and Tennessee Higher Education Commission through their support of the Center for Materials Processing, and the Paul and Madeline Bunch Fellowship (X.F., P.K.L.).
Keywords
- biomaterials
- electrochemical impedance spectroscopy
- high-entropy alloy
- modeling
- passivation
- polarization