Influence of scratch load and speed in scratch tests of bilayer powder coatings

The knowledge of the properties of the coatings in terms of scratch and wear resistance is of paramount importance in order to prevent the formation of severe damages. Nonetheless, dealing with the evaluation scratch or wear resistance of an organic coating can be troublesome. They can be strongly dependent on the status of the organic material as well as on the contact condition, applied load and strain rate. Besides, reliable responses cannot be achieved if an appropriate experimental design and a combined usage of proper equipments is not scheduled. In this respect, the present analysis deals with the application of variable speed and load scratch tests to characterize the scratch response and wear resistance of bilayer metal flakes powder coatings. Experimental findings allowed the achievement of consistent trends of the deformation response vs. curing temperature, scratch load and speed as well as their empirical modelling. This way, the overall scratch resistance of the bilayer coatings could be usefully predicted on a broad range of operational conditions, thus providing helpful indications to paint manufacturers and coaters on how to best deal with the application of metal flake powders. © 2008 Elsevier B.V. All rights reserved.