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Received Nov 8, 2017; Accepted Feb 8, 2018

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Introduction

Corrosion problems have sparked a considerable attention because of their aggressiveness towards materials [1]. The most important application of steel is in the oil and gas pipelines, refineries, recovery units, and so forth. Acid solutions are usually used as acid pickling, acid descaling, and industrial acid cleaning [2]. The use of inhibitors is one of the best ways to protect metals and alloys against corrosion in acidic medium [3, 4]. The environmental toxicity of organic products has prompted the search for new eco-friendly substances readily available and effective molecules having very high inhibition efficiency [5, 6]. It is well known that organic compounds containing heteroatoms, such as sulfur, nitrogen, and oxygen, could be excellent for corrosion inhibitors [7]. The efficiency of these organic inhibitors is related to their ability to be adsorbed on metal surface which is influenced by some of their electronic and physicochemical properties such as electronic structure, steric factor, aromaticity, electronic density at donor site, and presence of functional groups [8, 9]. The inhibition process could be explained by a physical or chemical adsorption of these organic molecules into the surface of the metal, forming a protective layer to isolate the metal from the corrosion [10]. Some researchers explain that the inhibition process is related to the formation of donor-acceptor surface complexes between a vacant d-orbital of metal and π or free electron inhibitor containing heteroatoms [11, 12]. Moreover, in recent years, the thiosemicarbazones as corrosion inhibitors have been widely studied and have shown their good inhibition efficiency [13–17]. In addition, these compounds have demonstrated high potency inhibition that related to the presence of sulfur and nitrogen. These explain their ability to form complexes with different metals especially with steel [16, 18]. In addition to experimental studies, the density functional theory (DFT) is widely used to interpret the experimental results of the observed inhibition [8].

The aim of this work is to evaluate the corrosion kinetic parameters of steel and the adsorption thermodynamic parameters of some Monoterpenic Thiosemicarbazones in 1 M HCl solution. The...

  

 
 
 
  

  

 
 
 
 
 
 
 

 
              
 
 
 

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