Concept of surface integrity

From a materials engineering point of view, a surface is a zone separating a body from the surrounding environment. It corresponds to an interface (solid-gas, solid-liquid, solid-solid) with physical and chemical properties that depend on the composition of the material and the environment. The chemical composition and mechanical properties of this zone can be very different from those of the material's core. The term "surface" refers to a layer with a thickness of between 10 ^–2 and 10 ^–6 mm