Investigation of AlMgCu Alloy Corrosion in 0.5M NaCl: Polarization and EIS studies

Abstract

Analyzing the production and consumption of non-ferrous metals in the world, it can be stated that aluminum and its alloys are in the first place in the term of a growth rate. The accelerated rate of nonferrous metals consumption, demands for high-quality castings, as well as the economic aspect, certainly have influenced some changes, certain improvements and innovations in casting technologies and their application in corrosive environments. In this sense the aluminum alloys with copper and magnesium occupy a significant place. Stability corrosion tests often use the Tafel's method of potentiodynamic polarization, as well as the electrochemical impedance measurements. Also, a certain corrosion stability enhancements and reducing the metal corrosion rates can be achieved with the addition of small quantities of inhibitors in the aggressive corrosion ambience. A proper selection of inhibitors is very important for effective enhancement of the corrosion protection, bearing in mind that some types of the inhibitors slow down the corrosion only in a particular solution/metal system. Inhibitors are mainly used to improve the corrosion protection of metal parts in solvents and spaces of limited volume, such as: chemical devices, steam boilers, storage and etching equipment and similar devices. The inhibitors used in this study belong to anodic corrosion inhibitors whose role is to slow down the anodic process of metal dissolution, through creating an insoluble protective layer with the primary corrosion products that firmly adheres to the metal surface and thereby reduces the anodic surface.

Tafel Polarization and Impedance Studies of Al-7075 Alloy and Its Composites in Different Medium.

“…But in 4% and hybrid composite, the Ecorr shifts in negative direction as cathodic current increases . (13) Ecorr value shifts in positive direction in base alloy, 2% and 4% composites it indicates increase in anodic current, but in hybrid composites Ecorr shifts towards negative direction as cathodic current increases due to presence of graphite.…”

“…The surface morphology of base alloy and its composites was assessed by SEM after corrosion tests in different mediums. The SEM images of degraded base alloy sample and its MMCs is shown in (figure [11][12][13] shows pretty much uniform assault and less degradation of compound in neutral chloride medium. The higher rate of corrosion in 4% HCl medium may be due to the presence of intermetallic precipitates at grains.…”

“…Jelena scepanovic et.al [13] studied on corrosion behavior of Al-Mg-Cu alloys in uninhibited and inhibited 0.5M NaCl solutions.Corrosion rates and other corrosion parameters were estimated as a function of sample compositions. Estimations were performed utilizing potentiodynamic polarization, electrochemical impedance studies, and linear polarization tests.…”