Abstract
The abrasion and erosion resistance of six different coatings were evaluated in relation to their microstructure. The coatings were produced from six different powders: four containing WC and two containing CrC. Microstructural analysis highlights the relationship between the starting powder morphology and chemistry and the spray conditions in the development of the final coating microstructure. The wear performance of the coatings was evaluated according to the ASTM G-65 standard for the abrasion resistance and a slurry containing 0.66% of 180 μm alumina particles flowing at 20 m/s for wet erosion resistance. The results show that for all tested coatings the abrasion wear resistance is mostly governed by the hardness distribution. For the chrome carbide, coatings having the lowest hardness are the lest abrasion resistant. For the WC containing coatings, carbide debonding and pullout is the main wear mechanisms. The most resistant material being the WC-6Co-8Cr. All the coatings performed better than the D2 tool steel reference sample. The erosion wear resistance is controlled by the local hardness, the matrix properties and the droplet debonding. The most wear-resistant materials are the WC-Co-Cr cermets. The least wear-resistant materials are the clad CrC-20(NiCr) and the WC-Ni cermets.
