Mechanical and corrosion properties of (Ti,Si)N coating synthesized by cathodic arc plasma evaporation

Ti-Si-N coating is an alternative candidate to replace the conventional TiN coating especially for high temperature oxidation-resistance applications. Different (Ti,Si)N coatings were deposited on tungsten carbide (WC-Co) substrates by cathodic arc plasma deposition (CAPD) from TiSi alloy targets in a reactive nitrogen atmosphere varied between 0.13 Pa and 4.0 Pa. The nitrogen partial pressure has important effects on the deposition growth and microstructure of coatings. All our coatings presented hardness higher than conventional TiN coatings. It has been found that the microstructure, mechanical, and corrosion properties of the films were correlated to Si concentration in the coatings. The influences of increasing nitrogen partial pressure on the microstructure, mechanical and corrosion properties of the films lead to increasing Si concentration and decreasing grain size in the films. As the nitrogen partial pressure increased, the results showed that the hardness of the films ranged from 24-39 GPa, which were higher than that of TiN (21 GPa). The corrosion resistance of coatings tested in 1 N H2SO4 solution was confirmed that (Ti,Si)N coatings was better than TiN coating since the effect of Si add in TiN and more dense nano-crystalline structure formed. The results turned out that better mechanical properties and corrosion resistance of (Ti,Si)N coatings can be obtained in this study. (C) 2008 Elsevier B.V. All rights reserved.