Biomedical Engineering Reference
In-Depth Information
biocompatibility, and mechanical properties. Other alloys, like
stainless steel are still in use.
Figure 5.1
Corrosion susceptibility of various metals and alloys [55].
Corrosion resistance of biomaterials plays a key role in theirs
successful application in human body environments. All metals and
alloys undergo corrosion when they are in contact with body luids,
which are very aggressive due to the presence of chloride ions and
proteins. The passive oxide ilm shields the implant material from
the corrosion process and additionally provides protection before
releasing the harmful compounds from the implant or its surface
into the bone.
The oxide thickness can be increased by anodic oxidation,
resulting in different types of oxide (anatase, brukite, and rutile) and
theirs thickness. The oxide thickness determines the surface color.
The blood plasma is a highly aggressive environments for
metals and alloys, because the presence of a high concentration