TRIBOLOGICAL LABORATORY EVALUATION OF THIN HARD COATINGS

Thin hard coatings are currently being used in a large number of impor tant tribological applications, such as metal cutting tools, forming t ools, sliding bearings, seals, engine parts and other machine elements . Therefore the need to understand what decides the tribological respo nse of a coating composite in a given tribological system, and to be a ble to experimentally rank different composites, is becoming more and more pressing. One of the greatest challenges is to design and/or empl oy tribological laboratory tests that are suited for this kind of stud y, that is, tests that are able to correctly simulate different well-d efined tribological systems. The present paper deals, experimentally, with the problems of determining tribological coating properties. In p articular, the use of several tests, designed and developed at Uppsala University exclusively for the purpose of tribological characterisati on of thin hard coatings and coating composites, are presented and dis cussed. Some examples are given in the form of results from abrasion, solid particle erosion and sliding wear studies of several thin hard c oatings, e.g. TiN, CrN, NbN, and some multilayered combinations thereo f. (C) 1997 Elsevier Science S.A.