Comparative Analysis of the Corrosion Resistance of Titanium Alloys Intended to Come into Direct or Prolonged Contact with Live Tissues.

Florina Ionescu,Lucien Reclaru,Lavinia Cosmina Ardelean,Andreas Blatter

doi:10.3390/ma12172841

Florina Ionescu, Lucien Reclaru + Show 2 more

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https://doi.org/10.3390/ma12172841

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Abstract

The evaluation of the biological safety and degradation of materials is quite important for risk assessment in various biomedical applications. In this study, two procedures were followed to characterize the corrosion resistance of different Ti-based alloys. The first one consisted of performing specific electrochemical tests (open circuit potential, linear resistance polarization, Tafel plots, potentiodynamic polarization) in order to highlight their behavior to the general and localized corrosion. The static and dynamic fatigue cycles combined with crevice corrosion conducted on a new prototype have completed the study. The second procedure followed was a cations extraction investigation (by inductively coupled plasma mass spectrometry) in order to verify the ionic permeability of the oxides layers formed on the surfaces. Optical and scanning electron microscopy were used for surface analysis. It was noticed that in these two electrolytes, the bulk Ti-based alloys presented an almost similar general corrosion behavior. The small differences of behavior for Ti6Al4V scaffolds were correlated to the surface oxidation and roughness (owing to the selective laser melting process). The Ti alloys presented no traces of localized corrosion at the end of the test. The fatigue cycles revealed that a strong and adhesive oxides film was formed during the static cycles (difficult to remove even during the depassivation steps). The concentration of cations released was at the detection limit, revealing very good passivation films, in adequacy with the all the other results.

Highlights

In terms of biomaterial applications, one of the inconvenient aspects is degradation, which occurs as a result of the material’s interaction with the human body or physiological fluids
The βtransus no difference of composition the two areastemperature, was noted. titanium will be a mixture of α + β, if the material contains some beta stabilizers, or it will α if it contains no β stabilizers
Two different procedures were used to study the behavior of Ti-based alloys (Ti6Al4V, Ti45Nb, Two different procedures were used to study the behavior of Ti-based alloys (Ti6Al4V, Ti13Nb13Zr) in a physiological solution of 9 g/L NaCl and in artificial plasma bone

Summary

Introduction

In terms of biomaterial applications, one of the inconvenient aspects is degradation, which occurs as a result of the material’s interaction with the human body or physiological fluids. Corrosion resistance can be considered a vital property for biomaterial components andis associated with the problem of metallic ion release, which is potentially harmful for the organism. Ti-based alloys exhibit good corrosion resistance owing to Ti oxides on their surface, the nature, composition, and thickness of the protective oxide depends on the environmental conditions. Degradation occurs on the biomaterial’s surfaces as a result of the chemical reactions between the oxide film and the chloride or fluoride ions in the media. The biocompatibility of materials in contact with a living tissue becomes a puzzle in the overall picture evaluating the effects of chemicals toxicity that come in contact with us [1,2,3,4].

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