Abstract
A clean surface can be critical in surface engineering processes. Particles on the surface may interfere with the surface modification process causing defects and poor performance. Therefore, the level of cleanliness required in a particular application is defined by the final product performance and appearance. This paper describes a number of analytical techniques that are used to assess the cleanliness of a surface. Practical examples are also given of how these techniques have been used in industry to investigate problems associated with maintaining cleanliness levels and to identify sources of contamination.