DESGASTE DE RECUBRIMIENTOS WC-CO-NICRBSI TRATADOS TÉRMICAMENTE

Abstract

The thermal sprayed WC-Co coatings are commonly used in industrial applications in which wear resistance is needed. Nevertheless, the coatings often present certain problems like not melting or semi-molten particles, poor adhesion to the substrate, low cohesion between particles amongst each other, which could affect the behavior of the coatings. The aim of this work is to investigate the effect of the oxyacetylene flame post heat treatment on the wear resistance of a WCCo- NiCrBSi coating thermally sprayed using a high velocity oxy-fuel (HVOF) process on an AISI 1020 steel substrate. The wear behavior of the coatings with and without post heat treatment was evaluated by erosion test, rubber wheel tests and pin-on-disk tests. It was determined that the abrasion resistance of the post heat treated coatings increased 67% compared with the sample without treatment, which could be attributed to a less porosity, matrix hardening and better cohesion between the hard particles produced by the flame post heat treatment. Nevertheless, the erosive and sliding wear resistance did not improve significantly with the application of the post heat treatment. The coating`s microhardness did not change appreciatively as a consequence of post heat treatment.