Evaluation of high velocity oxy-fuel (HVOF) deposition process on erosion and abrasion resistance of tungsten carbide coatings

Erosion and abrasion are both wear processes in which a particle that strikes the surface removes material, either by impact (erosion) or contact (abrasion). These wear processes can cause damages to components, which can be protected by coatings to reduce the damage occurrence. Thermally sprayed coatings are considered as a candidate for a protective system against abrasion and erosion. The HVOF spray process is one of the most used thermal spray process due to the ability to produce dense coatings, with good values of hardness and toughness. Among the materials used in thermally sprayed coatings, WC-Co based coatings is one of the most used, as it offers a combination of high hardness, toughness and adherence which can provide a good wear resistance. In this work, the influence of different HVOF process, specifically the type of fuel used, on the residual stresses and properties of these coatings was studied. It was noted that coatings deposited by HVOF with kerosene fuel, presented higher compressive residual stresses and lower roughness, compared with coatings deposited by HVOF process with gas fuel. It was also observed that the coatings with higher compressive residual stress provide a better wear resistance