Tribocorrosion of metallic implants
In some biomedical applications, implant materials can be exposed to very
complex service conditions including static and dynamic loading and relative
motion with soft or hard surfaces in contact. This, together with the corrosiveness
of physiological fluids can lead to enhanced degradation processes.
Tribocorrosion can be defined as the degradation caused by the combined
effect of corrosion and wear. Implant materials used to restore the function of
parts of the musculoskeletal system are a typical example of applications where
wear-corrosion processes can take place. Biomaterials used for hip and knee
artificial implants are subjected to the static load of body weight and dynamic
loads due to activities such as walking or climbing stairs, and relative motion
between surfaces due to the range of motion of the surfaces. The combined
effect of wear and corrosion can take place on articulating surfaces but also on
other surfaces in contact due to variable loading and unloading, as shown in
Figure 1.3(a). Fracture fixation devices and dental implants (Figure 1.3(b) and
1.3(c)) are other examples where the combined effect of wear and corrosion
can take place due to small range motion produced during activities such as walking or chewing, respectively
The degradation due to tribocorrosion processes cannot be considered as
the simple addition of wear degradation and corrosion degradation, but the effect
of the synergies created between them should also be considered. Equation