Biomedical Engineering Reference
In-Depth Information
In such cases one has either boundary film lubrication, where some lubrication
components act to partially separate the surfaces, or dry lubrication, where there is
no separating effect of the lubricant.
Fig. 2.11
Improved Wettability of Ceramic Surfaces
Human joint motion is characterized by a predominance of boundary and the
more destructive dry lubrication. Boundary lubrication is improved, and the
period of dry lubrication is reduced, if the wettability of the surfaces is increased.
2.5.3 Adhesive Wear
This type of wear results from localized welding and tearing, rather than gouging,
of the contacting surfaces.
When opposing asperities contact each other the greatly localized nature of the
contact produces such high stresses that if the two materials in contact are similar
they will become welded or adherent. Translation of one with respect to the other
will then produce tearing or rupture of one or both of the asperities as illustrated in
Fig. 2.12.
