Determination of the Fatigue Resistance of HVOF Thermal Spray WC-CoCr Coatings by Means of Impact Testing

Abstract

Impact testing is an efficient experimental procedure that enables the determination of the fatigue resistance of mono- and multi-layer coatings deposited on various substrates, which was not possible with the common testing methods previously available. In this paper an advanced impact tester, able to assess the fatigue failure resistance of coatings working under cyclic loading conditions, is presented. The fatigue failure of the tested coatings was determined by means of scanning electron, optical microscopy, and EDX analysis. The test results are recorded in diagrams containing the impact load versus the number of successive impacts that the examined coatings can withstand. From the experimental results it was concluded that a hard, wear resistant HVOF thermal spray WC-CoCr coating deposited on P91 steel substrate presents a high fatigue resistance.