Evaluation of High Velocity Oxy-Fuel (HVOF) Deposition Process on Erosion and Abrasion Resistance of Tungsten Carbide Coatings

摘要

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 candidates for a protective system against abrasion and erosion. The HVOF spray process is one of the most used thermal spray processes due to the ability of producing dense coatings, with good values of hardness and toughness. Among the materials used in thermally sprayed coatings, WC-Co based coatings are often 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 parameters, 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 liquid fuel, presented lower porosity, compared with coatings deposited by gas fuel. It was also observed that the coatings with lower porosity provide a better abrasion resistance, meanwhile the erosion was controlled by toughness for 30° and higher hardness for 60° of impact angle.