Testing of the Impact Load of Thin Hard Nanocomposite, Multilayer and Monolayer Coatings

To evaluate the impact resistance of thin hard nanocomposite, multilayer and monolayer coatings in dynamic loading wear applications an impact test has been used. An impact testing of the coatings was proposed by Knotek et al in the 1990s. During testing the specimen is cyclically loaded by tungsten carbide ball that impacts of the coating/substrate surface. The test simulates a wide range of tribological systems.

For testing we use the prototype device developed in collaboration with Brno University of Technology. The impact testing is used to predict the fatigue strength of hard PVD monolayer and nanocomposite coatings. The micrographs inserted in Figs. 1 and 2 shows the imprints that occurred at different number of impacts on the sample.

Multilayer and nanocomposite coatings possessing high toughness have potential to show better performance than monolayer one. The impact wear resistance of the coating can be improved increasing its elasticity to accommodate the substrate deformation.

Test of CrN layer on steel and test of TiN layer on WC and on steel Test of the numbered specimen