Abstract
Cobalt chromium molybdenum alloy (CoCrMo) is widely employed in the orthopedic device industry due to a combination of properties that include low wear, high mechanical strength, and high corrosion resistance. However, when used as the bearing component of total hip implants, this material can be susceptible to wear and corrosion, which can be triggered or exacerbated by factors such as changing pH, biological fluids and cell interactions, particle release, and friction. The physiological fluid, which is composed of electrolytes, proteins, and other organic species, plays a critical role in the tribological behavior of CoCrMo alloy. The aim of this work is to generate a proteinaceous layer electrochemically and carry out nanoscale mechanical and surface evaluation of CoCrMo to understand the feasibility of a pre-treatment on this material. The treatments consisted of electrolytes, with different protein concentrations, and pre-selected transpassive potentials at +0.6, +0.7 and +0.8 V and a passive potential of −0.4 V. These observations will help in determining the electrolyte concentration and potential combination that would yield the most protective film layer. The results demonstrated that all the positive transpassive potentials and electrolyte combinations led to surface degradation processes causing more material removal as seen by the formation of localized corrosion at carbide and grain boundaries. Only the negative potential of −0.4 V, used by itself as a pre-treatment and in combination with an electrolyte with 30 g/L of bovine calf serum (BCS), demonstrated more homogeneous oxide layer and proteinaceous layer distribution respectively.
| Original language | English (US) |
|---|---|
| Article number | 15 |
| Journal | Journal of Bio- and Tribo-Corrosion |
| Volume | 2 |
| Issue number | 3 |
| DOIs | |
| State | Published - Sep 1 2016 |
Funding
Acknowledgments The authors would like to thank the University of Texas at Dallas for providing resources for this research through startup funds (D. Rodrigues). We also thank The Vascular Mechanobiology Lab (University of Texas at Dallas) for providing access to the AFM facilities and the fellowship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) (IMG). The authors from Rush University Medical Center would like to recognize and thank funding from the NSF (FDN 1160951) and intellectual contributions and support from Dr. Wimmer (RUMC) and Dr. Pourzal (RUMC) and Dr. E. Martin (NU). We would also like to thank The College of Dentistry at The University of Illinois at Chicago, Chicago, IL and The Department of Orthopedics, Rush University Medical Center, Chicago, IL for providing both funding and lab facilities.
Keywords
- Cobalt chromium molybdenum
- Coefficients of friction
- Electrochemical and mechanical degradation
- Third-body particle wear
- Transpassive potentials
- Tribological behavior
ASJC Scopus subject areas
- Materials Science (miscellaneous)
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry