Contents lists available at ScienceDirect Progress in Organic Coatings journal homepage: www.elsevier.com/locate/porgcoat Exploring the corrosion inhibition of magnesium by coatings Formulated with nano CeO 2 and ZnO particles T. Saravanakumar a , V. Kavimani b , K. Soorya Prakash b , T. Selvaraju a, ⁎ a Department of Chemistry, Bharathiar University, Coimbatore, 641 046, India b Department of Mechanical Engineering, Anna University Regional Campus, Coimbatore, 641 046, India ARTICLE INFO Keywords: CeO 2 /ZnO composite coating Doctor blade method Corrosion resistance Polarization ABSTRACT The objective of the work is to identify the anticorrosive property synthesized Nano ZnO rods and CeO 2 particles. Both ZnO and CeO 2 have good anticorrosion behavior; this materials are tested with and without composition to identify the corrosion inhibition behavior. The result reveals the high protection rate, which was accomplished by the composition. In this research, a detailed investigation of the corrosion inhibition performance of mag- nesium (Mg) substrate coated nanoparticles like cerium dioxide (CeO 2 ), zinc oxide nanorods (ZnO) and CeO 2 / ZnO composites were studied. Synthesized nanoparticles were characterized by various physio-chemical tech- niques. Surface morphology of the developed set of specimens was scrutinized through SEM and EDAX, which established a clean surface coating with minimal defects attainment through doctor’s blade method. Electrochemical corrosion behavior of Mg substrates coated with definite proportions of CeO 2 , ZnO and CeO 2 / ZnO composites were conceded in 3.5 wt. % NaCl using Tafel polarization and electrochemical impedance spectroscopy. Thus the developed CeO 2 /ZnO composite coating exhibits i corr of 0.905 (A cm -2 ) and corrosion rate was 0.81 × 10 -5 mpy better corrosion resistance compared to bare Mg or CeO 2 or ZnO coatings. 1. Introduction Magnesium and its alloys pose unique properties such as low den- sity, better damping resistance with high specific strength are used in a wide range of applications such as structural, electronics and industrial fields. Alternatively, Mg possesses low chemical stability and poor corrosion resistance, which limits its application. Nevertheless, several corrosion prevention techniques are available to improve the corrosion resistance of Mg-based alloys, such as surface modification and com- posite fabrication [1–3]. As a result, surface modification techniques have been considered to be an effective method for Mg to improve the inhibition of corrosion from saline environment. Various surface mod- ification techniques were adopted by researchers to reduce the corro- sion rate of Mg which includes electroless plating, physical vapor de- position, plasma electrolytic oxidation, sol-gel deposition, chemical conversion treatments and polymer coatings [4,5]. In addition, polymer based self-healing coatings are also considered as the effective method for corrosion inhibition. However self-healing coating requires the rapid and sustained release of the healable inhibitor molecules to achieve optimum anticorrosion efficiency. The nanocontainers with high loading capacity, optimized size and shape are a highly desirable factor in self-healing coating because intelligent anticorrosion coating suffers from their inability to receive any supply of healable inhibitors [6–8]. Alternatively, metal oxide based organic coatings were also preferred to improve the corrosion resistance behavior of Mg in ag- gressive media. Mostly, efficiency of coating in corrosive medium were depended upon the properties of corrosion inhibitors [9–12]. For ex- ample, Cr conversion coatings were developed over base metal in past years to sacks the oxidative attack. Conversely, the usage of Cr was progressively restricted due to the high toxicity of the hexavalent Cr compounds. To elude this downside, the new environmental-friendly pre-treatments such as rare earth metals viz. cerium, tantalum or carbon allotropes like reduced graphene oxide, ceramic oxide particles and also phosphate conversion treatments have been actively devel- oped in the recent decades [13–17]. As a result few researches in which cerium and zinc oxide based coating were adopted to improve the corrosion resistance of substrate material. The cerium oxide and polymer coating over AZ31 Mg alloy using hydrothermal method, investigates the corrosion behavior of developed coating using polarization and hydrogen evolution method under 3.5 wt.% NaCl exposes minimum i corr 1.217 × 10 -10 A cm -2 [18]. CeO 2 particle based coating over AZ31 Mg, synthesized by using plasma arc oxidation, corrosion behavior of the coating is identified by polar- ization method under 3.5 wt.% NaCl, which exhibits i corr https://doi.org/10.1016/j.porgcoat.2019.01.006 Received 23 October 2018; Received in revised form 11 December 2018; Accepted 4 January 2019 ⁎ Corresponding author. E-mail address: dr.t.selvarajuresearchgroup@gmail.com (T. Selvaraju). Progress in Organic Coatings 129 (2019) 32–42 0300-9440/ © 2019 Published by Elsevier B.V. T