Progress in Organic Coatings 84 (2015) 50–58 Contents lists available at ScienceDirect Progress in Organic Coatings j o ur nal ho me pag e: www.elsevier.com/locate/porgcoat The application of polycarbazole, polycarbazole/nanoclay and polycarbazole/Zn-nanoparticles as a corrosion inhibition for SS304 in saltwater Murat Ates a,∗ , Ali Tuncay Özyılmaz b a Department of Chemistry, Faculty of Arts and Sciences, Namik Kemal University, Degirmenalti Campus, 59030 Tekirdag, Turkey b Department of Chemistry, Faculty of Arts and Sciences, Mustafa Kemal University, Tayfur Sokmen Campus, 31000 Antakya, Turkey a r t i c l e i n f o Article history: Received 24 April 2014 Received in revised form 25 October 2014 Accepted 7 February 2015 Keywords: Polycarbazole Nanoclay Zn-nanoparticles Corrosion protection EIS SS304 a b s t r a c t Polycarbazole (PCz), polycarbazole/nanoclay and polycarbazole/Zn-nanocomposites were chemically and electrochemically synthesized on a stainless steel (SS304) electrode. The modified electrodes were characterized by electrochemical methods (CV and chronoamperometry), Fourier transform infrared spectroscopy (FTIR)-attenuated transmission reflectance (ATR), scanning electron microscopy (SEM)- energy dispersive X-ray analysis (EDX), four point probe, electrochemical impedance spectroscopy (EIS), and equivalent circuit model of R s (Q c (R c (Q p R ct ))). The electrochemical behavior of the modified films on SS304 was assessed by open circuit potential monitoring, potentiodynamic polarization and EIS mea- surements to test the corrosion protection efficiency against 3.5% NaCl solution. PCz, PCz/nanoclay and PCz/nanoZn films obtained by chemical method coated on SS304 electrode exhibited better corrosion protection performance compared to the films obtained by the electrochemical method. This result may be attributed to the effective formation of a thin and protective layer. The highest protection efficiency (PE = 99.81%) was obtained for chemically synthesized PCz films. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Metal plating is a technique widely used to protect oxidizable metals due to its high resistance to corrosion and good mechani- cal properties. Yet, the application of zinc plating and its alloying components in various industrial sectors—including the automo- tive, electric and electronic industry—is insufficient to protect the oxidizable metals. The protection of steel against corrosion by using organic molecule coating has been the subject of consid- erable research conducted in recent years [1,2]. The conducting polymers have been widely studied for many applications, such as the improvement of corrosion resistance of the components used as mechanical parts, particularly in automotive, electric and elec- tronic industry [3–5]. These materials can constitute an effective physical barrier against corrosive products, such as O 2 , H + and Cl - . Conducting polymers have been extensively investigated for potential application in anticorrosion protective coating and have ∗ Corresponding author. Tel.: +90 282 250 2607; fax: +90 282 250 9925. E-mail address: mates@nku.edu.tr (M. Ates). URL: http://www.atespolymer.org (M. Ates). been applied to a variety of metal surfaces, as first suggested by MacDiarmid [6]. According to the extant literature sources, carbazole and N-vinylcarbazole were electrocoated on copper electrode and corrosion protection ability against 0.5 M NaCl solution was investi- gated in more detail [7]. Both polymers were successfully protected against 0.5 M NaCl solution. Conducting polymers have also been recently studied on Fe, Al, and Zn metals [8]. Moreover, 4-methyl carbazole-3-carboxylic acid was successfully studied on a stainless steel (316L) electrode with LiClO 4 /CH 3 CN solution. The corrosion test results indicated that PCz exhibited effective anodic protection in corrosive test solution [9]. Conducting polymers not only posses barrier properties of metals, but also prevent the corrosion ions reaching the metal surface [10], due to their redox electro-active behaviors [11]. Electrochemical impedance spectroscopy (EIS) pro- vides an accelerated measure of the resistance of a coating to ion transport phenomena and can thus yield long-term insight into the effects of corrosion [12]. The main objective of the present study is to identify an effective, cost-efficient and easily available electrolyte for PCz, PCz/nanoclay and PCz/Zn-nanoparticles on SS304 substrates. Secondly, PCz and PCz/nanoclay, as well as PCz/Zn-nanoparticle nanocomposites have been synthesized uniformly, and are compact and adhere strongly http://dx.doi.org/10.1016/j.porgcoat.2015.02.013 0300-9440/© 2015 Elsevier B.V. All rights reserved.