Desgaste em recobrimentos duplex e monocamada a base de WC-Co

Abstract

The abrasive wear of a WC12Co/NiCrAl two layer coating, single layer WC12Co, and single layer 50%(WC12Co)50%(NiCr) on the as deposited and melted conditions was studied. The tests were performed at two different conditions, called mild wearand severe wear. Samples of the substrate material, AISI 1020 grade steel, were also studied for comparison. The surface of the materials was characterized before and after the wear tests using topographic parameters obtained by stylus profilometry. A Modified Plasticity Index was created to evaluate the nature of the contact betweenthe surfaces and the abrasive media. The lowest wear rates were found on the duplex coating on both severity conditions. The results show that the 50%(WC12Co)50%(NiCr) coatings have lower wear resistance than the WC12Co single layer and duplex coatings on both severityconditions. However, their wear rate was significantly lower than that of the steel. Although the 50%(WC12Co)50%(NiCr) coatings proved not to be the best choice in terms of wear resistance, they are resistant enough to produce good results on wear applications. The topographic parameters helped on the characterization of the wear mechanisms.The Modified Plasticity Index, defined as a function both of the surface characteristics and of the mechanical properties of the materials, can be used to compare the wear behavior of different surfaces/coatings.