Corrosion resistance of iron‐containing experimental titanium alloys exposed to simulated body fluids

• Published in: Materials and corrosion Vol. 73; no. 8; pp. 1298 - 1307
• Main Authors: Leshetla, Mogomotsi, Klenam, Desmond E., Merwe, Josias, Potgieter, Herman, Whitefield, David, Bodunrin, Michael O.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.08.2022
• Subjects: bioimplants; Biomedical materials; Body fluids; Corrosion potential; Corrosion rate; Corrosion resistance; Exposure; Hanks balanced salt solution; Lamellar structure; Linear polarization; low‐cost titanium alloys; Open circuit voltage; polarization resistance; Saline solutions; Simulation; Technology assessment; Titanium alloys; Titanium base alloys; Vacuum induction melting
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.202213076

In this study, experimental Ti–6Al–1V–3Fe, Ti–4.5Al–1V–3Fe, and Ti–3Fe alloys, as well as commercial Ti–6Al–4V alloy that were scaled up utilizing vacuum induction melting technology, were assessed for corrosion performance in simulated body fluids. The selected simulated body fluids were 0.9 wt% NaCl solution and Hanks balanced salt solution (HBSS). Open circuit potential and linear polarization scans were performed to understand the corrosion performance of the alloys. The surface of the alloys was examined before and after exposure to corrosive solutions using scanning electron microscopy. The results show that all the alloys exhibit good corrosion performance in simulated body fluids. The corrosion rates were less than 0.5 mm/year. Owing to higher corrosion potential and lower corrosion rate, Ti–6Al–1V–3Fe and Ti–4.5Al–1V–3Fe had the best resistance to corrosion in 0.9 wt% NaCl and HBSS, respectively. All the alloys consist of a fully lamellar structure with α and β phases. There was no evidence of severe deterioration on the exposed surface of alloys in the simulated body fluids. It is shown that scaling up experimental Ti–Al–V–Fe alloy from 10 g to ∼3 kg using a vacuum induction furnace did not cause the formation of beta flecks in the alloy, despite the iron content. The superior corrosion resistance of experimental Ti–4.5Al–1V–3Fe alloy over commercial Ti–6Al–4V in Hanks balanced salt solution indicates that the alloy can serve as a cheaper alternative to Ti–6Al–4V implants.