Applied Surface Science 371 (2016) 262–274 Contents lists available at ScienceDirect Applied Surface Science journal h om epa ge: www.elsevier.com/locate/apsusc Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings Vishnu Shankar Dhandapani a,b , Ramesh Subbiah c,d , Elangovan Thangavel a,b , Madhankumar Arumugam e , Kwideok Park c,d , Zuhair M. Gasem e , Veeravazhuthi Veeraragavan a,∗ , Dae-Eun Kim b,f,∗∗ a PG & Research Department of Physics, PSG College of Arts & Science, Coimbatore 641 014, Tamil Nadu, India b Center for Nano-Wear, Yonsei University, Seoul 120-749, Republic of Korea c Center for Biomaterials, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea d Department of Biomedical Engineering, Korea University of Science and Technology (UST), Daejon 305-333, Republic of Korea e Center of Research Excellence in Corrosion, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia f Department of Mechanical Engineering, Yonsei University, Seoul 120-749, Republic of Korea a r t i c l e i n f o Article history: Received 3 November 2015 Received in revised form 22 February 2016 Accepted 22 February 2016 Available online 26 February 2016 Keywords: Amorphous carbon 316L SS Tribological property Preosteoblasts Corrosion a b s t r a c t Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and bio- compatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelec- tron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp 2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts pro- liferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique. © 2016 Elsevier B.V. All rights reserved. 1. Introduction 316L stainless steel (SS) is one of the most commonly used structural alloys and has received considerable attention in ortho- pedic applications due its versatile properties. For example, it has been widely used in orthopedic surgeries particularly as fix- atives to support the fractured bones and also in various other applications [1–4]. However, release of ions such as nickel, chro- mate, and molybdenum in the serum after implantation and ∗ Corresponding author. ∗∗ Corresponding author at: Department of Mechanical Engineering, Yonsei Uni- versity, Seoul 120-749, South Korea. Fax: +82 2 312 2159. E-mail addresses: vv.vazhuthi@gmail.com, vv vazhuthi@rediffmail.com (V. Veeraragavan), kimde@yonsei.ac.kr (D.-E. Kim). associated allergic reactions have become a critical problem for long-term implantation of 316L SS [5]. In order to overcome this problem, surface modification of SS by coatings has been explored to enhance and control the corrosion resistance and biocompatibil- ity of the material. Various research groups have investigated the effect of different surface coatings on the improvement of mate- rial properties and biocompatibility using various cell types [3–9]. Furthermore, several types of coatings on SS have been investi- gated for the enhancement of biocompatibility [10–13]. Sharifnabi et al. deposited Mg-substituted fluorapatite coating on 316L SS and found that corrosion resistance increased in normal saline and Ringer’s solution [14]. They also found that it reduced the amount of metal ion released from 316L SS. Enhanced corrosion resistance against SBF solution and hydroxyapatite layer growth on metal surface were observed on porous titanium dioxide [15] and porous zirconium dioxide [16] coated 316LL SS by Nagarajan http://dx.doi.org/10.1016/j.apsusc.2016.02.194 0169-4332/© 2016 Elsevier B.V. All rights reserved.