Resumo

AMAYA AVILA, Ariel Augusto; PIAMBA TULCAN, Oscar Edwin  e  OLAYA FLOREZ, Jhon Jairo. Vanadium carbide coatings produced on gray cast iron using the thermo-reactive deposition/diffusion technique. Ingenier. mecáni. tecnolog. desarroll [online]. 2015, vol.5, n.3, pp.333-338. ISSN 1665-7381.

Vanadium carbide (VC) coatings were produced on gray cast iron (GCI) with a pearlitic matrix, randomized lamellar graphite, and 3.5% of total carbon. The process was carried out in a molten borax bath at temperatures of 1173 K, 1223 K, and 1273 K for 2, 4, and 6 hours. Ferro vanadium was used as the carbide-forming element and aluminum as the reducing agent. Layer growth parameters were determined on the basis of classical kinetic theory. The coatings were characterized via scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and X-ray diffraction (XRD). In general, it was possible to produce a compact, continuous, homogeneous coating, and a smooth interface with the substrate was formed. Via XRD, the FCC phase of VC was observed, with a mixed orientation along the (111) and (200) crystal planes. Using AES, the presence of mainly vanadium at 437 eV and carbon at 272 eV was verified. Finally, by means of the electrochemical technique of potentiodynamic polarization in a 3% NaCl solution, it was found that the corrosion resistance of the VC-GCI system exhibited better performance than the substrate.

Palavras-chave : Vanadium Carbide; corrosion; cast iron; coating.