Review of non-destructive measuring methods for the assessment of surface integrity: a survey of new measuring methods for coatings, layered structures and processed surfaces

Even though the near-surface areas of precisely manufactured parts represen t only a few percent of the workpiece's material volume, they influence its functional behaviour, quality and lifetime significantly. Therefore, senso rs and measuring principles able to detect material changes, damage and pro cess influences in the near-edge zone are of increasing importance. However , they have to meet industrial purposes concerning accuracy, measuring time , robustness and costs. In addition, they should work non-destructively and should offer the capability for integration in a production line. (C) 1999 Elsevier Science Inc. All rights reserved.