Introduction to Surfaces and Surface Metrology

Abstract

Components and systems used in and manufactured for technical applications consist of two distinct areas, a bulk and a surface. The surface of a workpiece forms the interface to the surrounding. Its status is not invariant. Rather, water (vapor) and air and all in water or air solved or dispersed substances as well as temperature effects alter the surface gradually even without human influence. Changes that even affect the whole workpiece, like melting, corrosion, or abrasion, start at the surface. A technical surface can also carry signatures of processing techniques like grinding, lapping, or pitch polishing. Moreover, the workpiece can be given new properties by structuring, deposition, or coating that affect primarily the surface. In summary, the surface often determines the functionality and the appearance of the component and is of importance for the proper function and performance of the manufactured component. Therefore, it is essential for product development, process control, quality control, and failure analysis to examine the surface of a workpiece.

I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of science, whatever the matter may be.

Lord Kelvin (1824–1907)