Study of the Properties of WC-Co Nanostructured Coatings Sprayed by High-Velocity Oxyfuel

摘要

Interest in nanomaterials has increased in recent years. This is due to the potential improvement that size reduction to nanometric scale could provide in properties like hardness, toughness, wear, and corrosion resistance. The current study is focused on WC-Co cermets, materials that are extensively used in applications requiring wear resistance. Two coatings were sprayed by high-velocity oxyfuel using both conventional and nanostructured cermets. Both materials were characterized by means of x-ray diffraction and scanning electron microscopy to study their phases and morphology. Cross-sectional images and microhardness values are given for both coatings. Friction wear resistance of the coatings was studied by ball-on-disk (ASTM G99-90), and abrasive wear resistance was quantified by rubber-wheel (ASTM G65-91). Finally, the corrosion resistance was studied by electrochemical techniques. Comparative results showed that the nanostructured coating has better properties than the conventional coating except in the dry abrasion wear test, where the wear rates are very similar.