3. Determination of mechanical surface characteristics

While the surface is first and foremost a geometric entity characteristic of the shape of a body, it is also the material envelope directly subjected to external aggression. As such, it has both aesthetic and protective functions. It is therefore important to be able to characterize the state of the surface, linked to geometric and physico-chemical parameters, as well as its mechanical, chemical and electrical behavior, etc., especially as the material in this zone does not always have the same structure as at the heart of the part.

For an analysis of the problem as a whole, the reader is referred to a general synthesis study [11] . We will confine ourselves here to the mechanical aspects, for which two main families of methods are used:

• One focuses...