Corrosion, tribology and tribocorrosion research in biomedical implants : progressive trend in the published literature

There has been significant progress in implant research during last the 10 years (2005–2015). The increase in the elderly population coupled with a lack of proper physical activity is a potential cause for the sudden increment in implant usage. Implant life and performance are influenced by several parameters; however, literature showed that corrosion, tribology, and tribocorrosion processes of implant materials are main concern and driving mechanisms in the degradation processes. There is currently a large need for research in this area. Furthermore, there has been no recent systematic literature review to analyze the progress of research and published work in this area. The objective of this work is to provide a trend in the published articles in the area of corrosion, tribology, and tribocorrosion during last century, with emphasis on the progress over the last 10 years. The paper also tries to report the current state-of-the-art research in the area of corrosion, tribology, and tribocorrosion research in bio-implants based on number of published articles. The reviews demonstrate that during the last 10 years, there has been significant progress in implant research, particularly in the tribocorrosion area, however, significantly lower than tribology and corrosion research

Mechanically assisted electrochemical degradation of alumina-TiC composites

Alumina-TiC composite material is a tough ceramic composite with excellent hardness, wear resistance and oxidation resistance in dry and high-temperature conditions. In aqueous conditions, however, it is likely to be electrochemically active facilitating charge transfer processes due to the conductive nature of TiC. For application as an orthopedic biomaterial, it is crucial to assess the electrochemical behavior of this composite, especially under a combined mechanical and electrochemical environment. In this study, we examined the mechanically assisted electrochemical performance of alumina-TiC composite in an aqueous environment. The spontaneous electrochemical response to brushing abrasion was measured. Changes in the magnitude of electrochemical current with abrasion test conditions and possible causal relationship to the alteration in surface morphology were examined. Results showed that the alumina matrix underwent abrasive wear with evidence of microploughing and grain boundary damage. Chemical analysis revealed TiO2 formation in the abraded region, indicating oxidation of the conductive TiC domain. Furthermore, wear debris from alumina abrasion appeared to affect reaction kinetics at the composite-electrolyte interface. From this work, we established that the composite undergoes abrasion assisted electrochemical degradation even in gentle abrasive conditions and the severity of degradation is related to temperature and conditions of test environment

Tribocorrosive behaviour of commonly used temporomandibular implants in a synovial fluid-like environment: Ti-6Al-4V and CoCrMo

The temporomandibular joint implant metal alloys, Ti6Al4V and CoCrMo, (n = 3/group) were tested under free-potential and potentiostatic conditions using a custom-made tribocorrosion apparatus. Sliding duration (1800 cycles), frequency (1.0 Hz) and load (16 N) mimicked the daily mastication process. Synovial-like fluid (bovine calf serum, pH = 7.6 at 37 °C) was used to simulate the in vivo environment. Changes in friction coefficient were monitored throughout the sliding process. Changes in surface topography, total weight loss and roughness values were calculated using scanning electron microscopy and white-light interferometry. Finally, statistical analyses were performed using paired t-tests to determine significance between regions within each metal type and also independent sample t-tests to determine statistical significance between metal alloy types. Ti6Al4V demonstrated a greater decrease of potential than CoCrMo, a higher weight loss from wear (Kw = 257.8 versus 2.62 μg; p \u3c 0.0001), a higher weight loss from corrosion (Kc = 17.44 versus 0.14 μg; p \u3c 0.0001) and a higher weight loss from the combined effects of wear and corrosion (Kwc = 275.28 versus 2.76 μg; p \u3c 0.0001). White-light interferometry measurements demonstrated a greater difference in surface roughness inside the wear region in Ti6Al4V than CoCrMo after the sliding (Ra = 323.80 versus 70.74 nm; p \u3c 0.0001). In conclusion, CoCrMo alloy shows superior anti-corrosive and biomechanical properties. © 2013 IOP Publishing Ltd