Use of scanning white light interferometry in the characterization of wear mechanisms in thermal-sprayed coatings

Thermal spray coatings are widely used to reduce wear damage in certain engineering applications. There are several methods of measuring coating wear resistance. Among these, one of the easiest is the combination of the ball-on-disk test with interferometric measurements (noncontact profilometer). The main purpose of this article is to analyze the major wear mechanisms that occur in thermal-sprayed coatings tested under sliding conditions. This work shows how scanning white light interferometry can be easily used to study the wear mechanisms of some coatings, and allows abrasive, adhesive, and fatigue wear mechanisms to be distinguished. The main features of each of these mechanisms observed through the images of the interferometric microscope are reported.