Cyclic voltammetry measurements of different single-, bi- and multilayer TiN and single layer CrN coatings on low-carbon-steel substrates

Abstract

Hard nitride coatings deposited by plasma enhanced physical vapor deposition are very often used as wear protective coatings. The electrochemical properties of single layered TiN and CrN films have been compared to bi- and multilayered Ti/TiN coatings deposited on low carbon steel substrate. Cyclic voltammetry in acetate buffer has been applied to measure the porosity and corrosion resistance of the coatings. A quantity called the porosity index has been introduced to compare the quality of the deposited coatings. The results showed that the intermediate Ti layer improves the protective ability of the coatings. The changes in the substrate through the defects caused by electrochemical treatment have been observed and analysed using Conversion Electron Mössbauer Spectroscopy (CEMS), Auger Electron Spectroscopy (AES) and electrothermal atomic absorbtion analysis.