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

Hard nitride coatings deposited by plasma enhanced physical vapor depositio n are very often used as wear protective coatings. The electrochemical prop erties of single layered TiN and CrN films have been compared to bi- and mu ltilayered 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 abil ity of the coatings. The changes in the substrate through the defects cause d by electrochemical treatment have been observed and analysed using Conver sion Electron Mossbauer Spectroscopy (CEMS), Auger Electron Spectroscopy (A ES) and electrothermal atomic absorbtion analysis. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.