Corrosion behavior of TiN-coated cutting carbide tools

Abstract

Hard coatings produced by physical vapor deposition (PVD) have been widely used as a thin protective film. The coatings can provide wear resistance, corrosion resistance, can be decorative and act as a diffusion barrier. Among the commercially available coatings, TiN (titanium nitride) is probably the most commonly used industrially for machining tools. The aim of our work is to study corrosion resistance of TiN coated carbide tools such as WC–Co (tungsten carbide with cobalt). The corrosion behavior of TiN coating was examined in naturally aerated aqueous 0.5 M NaCl solution. The study was performed by using potentiodynamic polarization (PP) and electrochemical impedance spectroscopy measurements (EIS), complemented with scanning electron (SEM) microscopy. The experimental impedance data are in good agreement with the polarization experiments. The TiN coating improves the corrosion resistance of carbide tools in NaCl solution.