Tribological behaviour of plasma-sprayed WC coatings with and without laser remelting

In this paper, the tribological properties of plasma-sprayed WC-Co coatings are studied, both before and after remelting of the coatings with a CO2 laser. The coatings were deposited onto steel substrates. The laser treatment induced changes in porosity, microhardness, coating-substrate adherence and wear resistance in dry and lubricated contact. The results demonstrate that laser remelting of plasma-sprayed WC-Co coatings improve their microstructure, and increase the microhardness and coating-substrate adherence. Both materials, treated and untreated, present a dry sliding wear behaviour that matches satisfactorily with Czichos' model, and the friction coefficient is very similar for the two materials; however, the remelted coatings are more wear resistant under dry contact conditions. (C) 2000 Published by Elsevier Science S.A. All rights reserved.