STUDY OF NIOBIUM-VANADIUM TERNARY CARBIDE COATINGS PRODUCED ON D2 TOOL STEEL BY THERMOREACTIVE DEPOSITION/DIFFUSION

Abstract

In  this  work,  the  deposition  of  niobium-vanadium  ternary  carbide  coatings  on  D2  tool  steel  by  thermoreactive deposition/diffusion  (TRD)  is  presented.  The  carbides  were  obtained  using  salt  baths  composed  of  molten  borax, ferro-vanadium, ferro-niobium and aluminum, varying its chemical composition, at a temperature of 1020 °C for 4 hours. The  coatings  were  observed  via  scanning  electron  microscopy  (SEM)  and  EDS  was  used  to  determine  the  chemical composition.  The  phases  presented  were  determined  using  x-ray  diffraction  (XRD),  and  nanoindentation  was  used  to measure hardness and elastic modulus. The electrochemical behavior was studied via potentiodynamic polarization curves to determine the rate of corrosion, and electrochemical impedance spectroscopy (EIS) was used to determine the resistance to polarization. The results were compared with the properties of the substrate without a coating, and in general, greater hardness and better corrosion resistance were observed in the coatings.