Micro-arc and thermal oxidized titanium matrix composites for tribocorrosion-resistant biomedical implants

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Sousa, L (Author) Other; Costa, NA (Author) Other; Rossi, A (Author) Other; Simoes, S (Author) FEUP; Toptan, F (Author) Other; Alves, AC (Author) FEUP

Journal

Title: Surface and Coatings Technology

Vol. 485

ISSN: 0257-8972

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 0 Citations

Other information

Authenticus ID: P-010-C4Z

DOI: 10.1016/j.surfcoat.2024.130854

Abstract (EN): Superior tribocorrosion resistance is offered by titanium matrix composites (TMCs) compared to their unreinforced matrix metal, but bioactivity concerns are raised for biomedical applications. Simple methods such as micro -arc oxidation (MAO) and thermal oxidation (TO) are employed to enhance the bioactivity and degradation resistance of Ti. However, the impact of those surface treatments on TMC surfaces is poorly understood. Therefore, the present work aimed to explore the influence of MAO and TO treatments on the surfaces of in - situ Ti-TiB-TiC and ex - situ Ti-B 4 C composites, and to assess their corrosion and tribocorrosion performance. Corrosion and tribocorrosion tests were conducted in phosphate-buffered saline solution (PBS) at body temperature. Electrochemical assays were performed by means of potentiodynamic polarization scans while additional potentiostatic tests were performed for the untreated ex - situ composites. Tribo-electrochemical assays were conducted under open circuit potential (OCP) and under normal loads of 0.5 and 10 N against a 10 mm diameter alumina ball in a reciprocating ball -on -plate tribometer. Results revealed reinforcement detachments in ex - situ composites after both treatments. This was primarily attributed to oxide layer growth at the reinforcement/reaction zone interface. Hence, the use of MAO and TO on ex - situ Ti-B 4 C composites may not be appropriate for biomedical applications, mainly because the B 4 C particles tend to detach during the treatment. In contrast, TOtreated in - situ composites displayed excellent combination of corrosion and tribocorrosion performance, even under elevated applied loads, mainly due to the existence of the oxygen diffusion zone (ODZ) beneath the oxide surface produced by TO, together with the more stable electrochemical properties observed during steady -state conditions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11