The use of electrochemical techniques to evaluate the corrosion performance of metallic biomedical materials and devices

Abstract

The corrosion performance of metallic biomedical materials and devices is commonly evaluated using electrochemical techniques. Although test standards involving such techniques have been released to address some forms of corrosion, a key issue is application of the results with regard to use of an implantable device in vivo. This review focuses on nitinol, 316L/LVM stainless steel, and Co-Cr alloys and is intended to provide some perspective on the significance of results from tests concerning general corrosion, localized corrosion, galvanic corrosion, and fretting corrosion of these alloys in simulated physiological solutions. It also examines the factors that could cause differences in the corrosion performance between in vitro and in vivo exposure, with the goal of providing some rationale for applying electrochemical characteristics obtained from the tests to predict the corrosion performance in vivo. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: Appl Biomater, 2018.

The Mechanism of Metallosis After Total Hip Arthroplasty

“…The effectiveness of an oxide layer as a protective barrier is a function of the oxide chemistry, thickness, and integrity. An oxide layer should be approximately 10 nm thick, chemically stable, uniform, defect-free, and adhere well to the metal substrate, with no subsurface intermetallic layer [22,23]. A uniform and defect-free oxide layer would provide optimal protection, since the release of metal ions and body fluid's reaction can occur across the entire surface area of a device; and implant oxide layer modifications to remove subsurface intermetallic layers as well as gross manufacturing surface defects have been efficacious [3,22].…”

“…Figure 2a illustrates local physical factors that play a role in the survival of a medical implant, such as pH, ion concentration, molecules, etc. Overall, cellular activities and proteins at the implant site first adsorb onto the metal surfaces aiding cell-metal interaction, and then, macrophages, monocytes, neutrophils, and other immune cells can secrete reactive oxygen species and cause a drop in local pH, which increases susceptibility to body fluid [22].…”

Effect of Protein and Mechanical Strain on the Corrosion Resistance and Cytotoxicity of the Orthodontic Composite Arch Wire

“…The electrochemical performance, such as breakdown of the oxide layer, has been hindered in the presence of proteins . During electrochemical testing, the high values of E corr in the protein groups indicated that the corrosion resistance was improved by protein. , The highest E pit of the mucin group suggested that the pitting corrosion tendency decreased in that solution. The largest E b – E corr in the mucin AS further illustrated that the pitting corrosion stability was higher.…”

Corrosion of Metals During Use in Arthroplasty

“…Corrosion involves the gradual destruction of materials by electrochemical reactions within their environment. , It is an exothermic process involving electrochemical degradation of metallic materials, propelled by the thermodynamics of a metal shift toward a low energy (chemical) potential, which usually takes place as an electron flows from the anodic region to the cathode . Corrosion occurs basically via three distinct stages of events: (1) Ions from the metal surface dissolve in oxidation in the electrochemical active surrounding releasing cations.…”

“…Pitting corrosion occurs mainly from a focal disintegration of the passive kinetic barrier of metallic implant alloys. , It is one of the most common forms of corrosion that attack passive alloys in orthopedic implants owing to the oxide film dissolution with small disruption of the passivation . Usually, when a microhole or pit forms as a result of depassivation on any segment of the metallic implant, it decreases the activation energy and creates an enabling surrounding for corrosion through the alteration of the area’s kinetics .…”