Corrosion fatigue in DLC-coated articulating implants: an accelerated methodology to predict realistic interface lifetime

ABSTRACT

We present a methodology to accelerate and estimate the lifetime of an interlayer under dynamic loading in body-like media. It is based on accelerating corrosion fatigue processes taking place at the buried interface of a Si-based adhesion-promoting interlayer in articulating implants on a CoCrMo biomedical alloy; the implants are coated with diamond-like carbon (DLC). The number of interface loading cycles to delamination is determined by reciprocal loading in corrosive fluid. Its dependence on the load is summarized in a Wöhler-like curve of a DLC/DLC-Si/CoCrMo system in body working conditions: cyclic stresses at 37 °C in phosphate buffered saline (PBS). The presence of oxygen as a contaminant strongly affects the lifetime of the interface under corrosion fatigue. The main parameters acting on the prediction, with a special emphasis on simulated in vivo conditions, are analyzed and discussed: the media (PBS, Milli-Q water, NaCl, Ringers’ solution and bovine calf serum), the load, the frequency and the composition of the interface determined by X-ray photoelectron spectroscopy.

Graphical abstract

KEYWORDS:

• Interface
• corrosion fatigue
• implant lifetime
• DLC coating

CLASSIFICATION:

• 30 Bio-inspired and biomedical materials
• 104 Carbon and related materials
• 212 Surface and interfaces
• 306 Thin film / Coatings
• 503 TEM, STEM, SEM
• 600 Corrosion Fatigue

Acknowledgments

The authors would like to express their gratitude to Bernhard Weisse, Sigfried Roos, Christian Affolter and Rowena Crockett for helpful discussions and comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Swiss National Science Foundation [PMPDP2_171412/1].