Electrochemical Behavior of SLM Ti–6Al–4V Alloy After Long Time of Immersion in Lactic Acid Environment

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 53; no. 6; pp. 2060 - 2070
• Main Authors: Banu, Alexandra, Preda, Loredana, Marcu, Maria, Dinca, Luciana Laura, Maxim, Monica Elisabeta, Dobri, Gabriel
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-06-2022; Springer Nature B.V
• Subjects: Alloys; Anodic polarization; Biomedical materials; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion currents; Corrosion potential; Corrosion resistance; Corrosion resistant alloys; Electrochemical analysis; Electrochemical impedance spectroscopy; Electrode polarization; Lactic acid; Laser beam melting; Materials Science; Metallic Materials; Nanotechnology; Open circuit voltage; Original Research Article; Photoelectrons; Spectrum analysis; Structural Materials; Submerging; Surfaces and Interfaces; Surgical implants; Thin Films; Titanium base alloys; Titanium dioxide; X ray photoelectron spectroscopy
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-022-06648-8

The corrosion behavior of selective laser melted Ti–6Al–4V alloy (SLM Ti–6Al–4V) was assessed in 0.1 M lactic acid + 0.1 M NaCl environment (pH 2.5) after 1150 hours of immersion at 37 °C and was compared with that of wrought Ti–6Al–4V alloy. Corrosion potential
E
cor
(
E
cor
= 0.083 ± 0.02 V) and corrosion current
i
cor
(
i
cor
= 0.145 ± 0.05 μA cm
−2
) of SLM Ti–6Al–4V alloy, estimated from anodic polarization tests, are under minimum recommended values for biomaterial surgical applications. Based on open-circuit potential (OCP) investigations, one may infer that this good corrosion resistance is due to the formation of a fast and stable protective oxide layer. According to X-ray photoelectron spectroscopy (XPS) results, this protective oxide layer is mainly formed from TiO
2
. From electrochemical impedance spectroscopy (EIS) investigations, a slightly lower corrosion resistance was observed at SLM Ti–6Al–4V alloy compared to the wrought one. Thus, the
R
1
associated with barrier film resistance of SLM Ti–6Al–4V is 339.1 kΩ cm
2
whereas that one of wrought Ti–6Al–4V is 780.1 kΩ cm
2
. These results are conspicuous ones because they point out that SLM technique, which allows obtaining easily customized implants without expensive costs, is a valid alternative for obtaining new alloys for medical applications.