1154 ISSN 2070-2051, Protection of Metals and Physical Chemistry of Surfaces, 2019, Vol. 55, No. 6, pp. 1154–1160. © Pleiades Publishing, Ltd., 2019. Formulation of Petrolatum/Clay Nanocomposite Coating and Characterization of its Corrosion Resistance Properties Maryam Ghiasvand a, c, *, Davood Zaarei b , Iman Danaee a , Babak Mogoie c , and Hanyeh Salehi Nasab a a Technical Inspection Engineering Department, Petroleum University of Technology, Abadan, Iran b Polymer Engineering Department, Technical Faculty, South Tehran Branch, Islamic Azad University, Tehran, Iran c Technical Inspection Engineering Department, Seven Distribution of Iranian Gas Transmission Company, Hamedan, Iran *e-mail: mghiasvand1369@gmail.com Received October 3, 2018; revised February 19, 2019; accepted February 28, 2019 Abstract—Montmorillonite organoclay, in different amounts (between 1 to 5 wt %), was incorporated into the petrolatum using mechanical stirring and sonication process. Anti-corrosive properties of the com- pounded nanocomposites were investigated using salt spray and electrochemical impedance spectroscopy (EIS) methods. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy analysis (EDX) showed that the interlayer spacing of clays was increased after addition of pet- rolatum resin along with applying shear force and ultrasounication. Electrochemical analyses showed improvement in the barrier and anti-corrosive characteristics of formulated nanocomposite coatings. The best performance of formulated coatings was achieved with coating containing 1 wt % clay concentration. Keywords: petrolatum, organoclay, nanocomposite, coating DOI: 10.1134/S2070205119060157 1. INTRODUCTION Over the years, polymeric coatings have been developed due to their good protection properties. However, pristine polymeric coatings are still perme- able corroding agents such as water, oxygen and destructive ions like [1]. In order to enhance the barrier properties of these coatings, many researchers have proposed various kinds of additives such as extenders and inorganic pigments [2–4]. In comparison with conventional pigments, addi- tion of nanoparticles into the polymeric coatings offers a more economical method and more durable protection against corrosion [5]. Several researches have used inorganic nanolayer materials (e.g., smectic clays) and incorporated these materials into the organic polymeric matrices. These inorganic materials effectively increase the diffusion pathways of water and destructive ions and enhance the corrosion stabil- ity of the resultant coatings [6]. The corrosion resistance of organic coatings is widely evaluated by electrochemical impedance (EIS). EIS is nondestructive technique useful to rank the organic coatings since it provides the possibility of investigating systems with a high resistance owing to their dielectric properties. Moreover, it is also possible to detect the start of corrosion process at very early stage on the substrate [7]. Since almost all types of polymers are potentially permeable to corrosive spe- cies, exposure of polymeric coatings to corrosive envi- ronments results in swelling, ablation and variation in resistance and dielectric constant of the coating. These in turn change the protection characteristics of the coating system [8]. Because all these processes influence the response of metal coating system under application of small amplitude alternating potential signal, relevant information can be extracted from analysis of EIS spectra [9–11]. The effects of using nanomaterials on the proper- ties of different nanocomposite coatings have been evaluated. However, it seems a few research have been done on corrosion performance of petrolatum layered silicate nanocomposite coating [12–14]. Due to the special feature of petrolatum such as: low cost, anti-bacteria, anti-alga, little tendency to reaction and appropriate molecular structure, it have been used as separate coating or strip for the protection of steel structures specially buried pipelines [15, 16]. Kinoshita et al. [17] used petrolatum and titanium metallic cover as a coating for prevention of steel cor- rosion in ocean environment. The results showed the superior performance of coating against corrosion. Osma saber et al. [18] used nano-structured materials to improve physical characteristics of petrolatum waxes. The results indicated that the nano-hybrid Cl , - H, + - 2 4 and SO NEW SUBSTANCES, MATERIALS AND COATINGS