Microstructure, corrosion and tribological behaviors of TiAlSiN coatings deposited by cathodic arc plasma deposition Chi-Lung Chang a, ⁎, Jyh-Wei Lee b , Ming-Don Tseng a a Department of Materials Science and Engineering, MingDao University, Taiwan, ROC b Department of Mechanical Engineering, Tung Nan Institute of Technology, Taiwan, ROC abstract article info Available online 20 March 2009 Keywords: TiAlSiN coating Cathodic arc plasma deposition Corrosion Tribology Wear Comprehensive microstructure, corrosion and tribological investigation results of the TiAlSiN coating were presented and compared with the TiN and TiSiN coatings. These coatings were deposited on tungsten carbide substrates using Ti, TiSi and AlSi target by cathodic arc deposition system. The composition and structure of the coatings were characterized by utilizing SEM, XRD, TEM, and XPS analyses. The corrosion behavior of the coatings in 3.5 wt.% NaCl solution was studied by the interpretation of the electrochemical anodic polarization curves. The mechanical and tribological properties of the coatings were evaluated by nanoindentation and pin-on-ball tribometer. The results showed that the TiAlSiN coating exhibited a more excellent mechanical and corrosion resistance than the TiN and TiSiN coatings, which could be attributed to forming nano-composites structure with the incorporations of Al and Si into TiN coating. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Ti-based coatings, such as TiN, TiAlN, TiCN etc, have been widely used on cutting tools to prolong the lifetime and to improve the working performance because of their high hardness, low coefficient of friction [1–3]. However, when more rigorous use environmental is considered, the conventional Ti-based coatings show the insufficiencies, especially in hardness, oxidation resistance and chemical stability. Therefore, surface engineers incorporate Al, Si, Cr etc into TiN coating to achieve an improved performance. Among those coatings, TiSiN and TiAlSiN are attracting much more concerns because of increased hardness (N 35 GPa) and thermal stability compared with previous TiN coatings [4–7], which have been deposited using chemical vapor deposition (CVD) [13], plasma-enhanced chemical vapor deposition PECVD [8–12], sputtering [14,15], cathodic arc plasma evaporation [16–19], and so on. The goal of this work is to compare the structure and properties of TiN, TiSiN and TiAlSiN coatings prepared by cathodic arc plasma evaporation. The effect of adding Al and Si, believed to play a major role on structure changes of these films, is particularly concerned for enhanced hardness, corrosion and wear resistance. 2. Experimental details Polished tungsten carbide (WC-Co) was used as substrates. A dual target cathodic arc evaporation (CAE) system with straight-duct designed sources was used to deposit the three kinds of films in a single process, as shown elsewhere [20]. The macro-particles were reduced by a straight-duct in front of arc sources. The reactive gas is introduced through a manifold. The partial pressure of the reactive gas was controlled by the mass flow meters, and through each manifold the flow of gas (i.e. N 2 and Ar) can be introduced independently. The Ti, TiSi (80:20 at.%) and AlSi (80:20 at.%) alloy were used as targets that can interact with nitrogen gas to form TiN, TiSiN and TiAlSiN coatings. Ti/TiN interlayer was deposited by introducing Ar and/or N 2 gas in front of the Ti source. Various coatings, including TiN, TiSiN and TiAlSiN have been successfully deposited by using this deposition system. Details of the deposition parameters were listed in Table 1 . Surface and fracture morphologies of the coatings were observed by a field emission scanning electron microscope (SEM: TF-SEM JSM7000F). The microstructure of the films was characterized by transmission electron microscopy (TEM: JEOL 400EX). TEM specimens were obtained by the standard procedures of precision grinding, dimple grinding, and ion milling until perforation. Fourier transform Thin Solid Films 517 (2009) 5231–5236 ⁎ Corresponding author. Tel.: +886 4 8876660x8010; fax: +886 4 8879050. E-mail address: clchang@mdu.edu.tw (C.-L. Chang). Table 1 Details of the deposition parameters of cathodic arc plasma deposition process. TiN TiSiN TiAlSiN Substrate temperature (°C) ~280 ~280 ~280 Nitrogen partial pressure (Pa) ~2.6 ~2.6 ~2.6 Argon partial pressure (Pa) ~ 0.05 ~ 0.05 ~ 0.05 Substrate bias voltage (V) -150 -150 -150 Evaporation current (A) 60 60 60 Source to substrate distance (cm) ~ 15 ~ 15 ~ 15 Target materials Ti Ti, TiSi (20 wt.% Si) Ti, AlSi (12 wt.% Si) Reaction gas Ar, N 2 Ar, N 2 Ar, N 2 Interlayer/deposition time (min) Ti, 5 Ti, 5+TiN, 20 Ti, 5 + TiN, 20 Top layer/deposition time (min) TiN, 45 TiSiN, 25 TiAlSiN, 25 0040-6090/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.tsf.2009.03.082 Contents lists available at ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf