Wear is defined as progressive loss of material
from the surface of a solid body as a result of mechanical
causes, i.e. contact with and movement relative to a solid,
liquid or Gasesous opposing body. It manifests in the form
of small separated particles (wear particles) and in changes
to the material and shape of the tribologically stressed surface.
Wear can be looked on as an element of tribology.
Wear is of great economic significance,
since the service lives of machines and equipment are dependent
on it. Ceramics allow significant improvement to be achieved
here, as may be seen from the example of the fixed and control
washers in a water tap, or linings of aluminium oxide. Other
selected application fields include shaping technology, the
ready-mixed concrete industry, the textile industry, the paper
industry, metal cutting, pump construction, and large sectors
of chemical and process technology where, for instance, ceramic
fittings, slip ring seals and nozzles are used.