Surface Modification Technologies

Abstract

The present work has been conducted in order to assess the mechanical and tribological performance of a ZrN coating deposited onto a H13 steel substrate by means of a closed field unbalanced magnetron-sputtering ion-plating (CFUMSIP) process. The hardness and elastic modulus of the coated system have been determined by means of nanoindentation techniques. Dry and wet sliding wear tests, employing a tribometer under a ball-on-disc configuration, were carried out making use of an alumina ball as counterpart, with an applied normal load of 2 N at a constant speed of 5 cm/s. For the wet wear tests, a 3.5 wt% NaCl solution was used. The resulting wear scars were analyzed by means of both SEM and optical profilometry techniques. It has been determined that, during testing under the corrosive solution, the coating experiences a severe abrasive wear mechanism, due to the combined action of the alumina ball, the hard “debris” and the phenomenon of crevice corrosion. On the other hand, it has also been shown that the coated system is able to increase the wear resistance of the substrate by more than one order of magnitude, if the wear tests are carried out in air under the same conditions.