Electrochemical and Molecular Dynamic Investigation of Some New Pyrimidine Derivatives as Corrosion Inhibitors for Alumi
- PDF / 2,296,335 Bytes
- 15 Pages / 612 x 792 pts (letter) Page_size
- 56 Downloads / 202 Views
HYSICOCHEMICAL PROBLEMS OF MATERIALS PROTECTION
Electrochemical and Molecular Dynamic Investigation of Some New Pyrimidine Derivatives as Corrosion Inhibitors for Aluminium in Acid Medium N. S. Abdelshafi* Electrochemistry Research Laboratory, Ain Shams University, Faculty of Education, Chemistry Department, Roxy, Cairo, Egypt *e-mail: [email protected] Received December 20, 2019; revised May 15, 2020; accepted May 22, 2020
Abstract—A new class of corrosion inhibitors, namely, pyridine-2,6-diamine (PD) , pyrimidin-2-amine (PA), 6-amino-3,4-dihydropyrimidine-2(1H)-thione (ADT) and ethyl (R)-6-(4-chlorophenyl)-2-mercapto-4-methyl-1,6-dihydropyrimidine-5-carboxylate (EMMD) has been used. The influence of these pyridine-pyrimidine on the dissolution of aluminum in molar HCl has been investigated using impedance spectroscopy as well as potentiodynamic polarization and molecular dynamics simulations. Impedance spectroscopy data show that values of constant phase elements, CPE are decreased. Polarization resistance and protection efficiency increase with increasing concentration of pyridine-pyrimidine derivatives as the electric double layer increased. Electronic equivalent circuit of the investigated system is suggested. Potentiodynamic polarization results showed that these derivatives are mixed-type inhibitors with mainly cathodic action. Molecular simulations are used to simulate the adsorption of pyridine-pyrimidine, on the aluminum oxide substrate. Keywords: electrochemical impedance spectroscopy, potentiodynamic polarization, molecular dynamics, corrosion inhibition, equivalent circuit DOI: 10.1134/S2070205120050044
1. INTRODUCTION Aluminum and its different alloys have a wide spectrum of industrial uses due to their unique characteristics as corrosion resistance metal [1, 2]. For these reasons, the corrosion behavior of aluminum and its alloys has attracted several investigators in corrosion science [3–10]. Aluminum and its alloys have corrosion resistance towards a wide variety of corrosive media due to the development of a protective, tightly adhered passive layer on its surface. Acid solutions are used for pickling, etching chemically and electrochemically of aluminum and its alloys, but it shows aggressive corrosion in presence of hydrochloric acid [11]. To decrease the corrosion rate of aluminum in such solutions, it is very practical to add corrosion inhibitors. The corrosion of aluminum and its alloys and their corrosion inhibition by organic inhibitors in HCl solutions are extensively studied in the literature [3–10]. Some organic compounds that containing elements such as nitrogen, sulfur, and oxygen are considered as corrosion inhibitors for aluminum in hydrochloric acid solution, such as aromatic amines [12], aromatic aldehyde [13], aromatic acids [14, 15], aliphatic amines [16, 17], thiourea derivatives [18, 19],
Schiff bases [20], hydrazine derivatives [21], anionic surfactants [22, 23], cationic [24, 25], nonionic surfactants [26, 27], amino acids [28, 29], antibacterial drugs [30, 31], organ
Data Loading...
