Tribological Behavior of Cermet Coatings Deposited from Submicron WC-10Co-4Cr Powders Using HVOF Spraying

Abstract

In this paper, we prepared cermet coatings deposited from submicron WC-CoCr powders using high-velocity oxygen-fuel (HVOF) spraying process. The detailed microstructures, slurry erosion and sliding wear resistance of as-sprayed coatings were investigated. The slurry erosion test was performed in a rotating disk rig facility with circulating system using distilled water and 3.5 wt.% NaCl slurries. The sliding wear properties were evaluated by a pin-on-disk tribometer under different loads. The results showed that submicron coatings exhibited higher slurry erosion resistance in distilled water slurry than that in 3.5 wt.% NaCl slurry after three tests. The slurry erosion mechanism of the coatings was characterized by scratches and pull-out of carbide particle. With increasing load (from 10 N to 50 N), the coatings showed a reduction in average friction coefficient (from 0.52 to 0.44), and an increase in mass loss (from 3.3 mg to 11.4 mg). The evolution of the sliding wear characteristics of the coatings with the increase of the load was micro-cracks, carbide particle pull-out, spallation, and massive exfoliation. The sliding wear mechanism of the coatings under different loads was primarily abrasive wear. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19507