Mariela Rendón Belmonte, José Trinidad Pérez Quiroz, Benjamín Valdez Salas, Miguel Martínez Madrid, Andrés Torres Acosta, Jesús Porcayo Calderón and Miguel Schorr Wiener
The purpose of this paper is to characterize the surface of steel under cathodic protection while submerged in seawater, to understand the mechanism that controls the operation of…
Abstract
Purpose
The purpose of this paper is to characterize the surface of steel under cathodic protection while submerged in seawater, to understand the mechanism that controls the operation of the protection system.
Design/methodology/approach
Steel rods were immersed in seawater and NaCl solution with applied cathodic protection. The experimental methodology included monitoring of corrosion potential (Ecorr), galvanic current (Igalv) protection potential (Eprotection) and the depolarization potential of steel during the time of exposure. In addition, the chemical composition of the steel surface was assessed using a Scanning Electron Microscope (SEM).
Findings
In this research it was determined that the effectiveness of the CP system was mainly attributable to the formation of an iron oxide film on the steel surface.
Research limitations/implications
It is necessary to carry out analysis of the chemical composition of deposits formed on the steel surface, perhaps using X‐ray diffraction (XRD), to verify the presence of a protective oxide.
Practical implications
Deposits on the steel surface have the beneficial effect of reducing the current required for efficient protection. Deposit formation therefore is of economic interest, as it decreases the cost of protection.
Originality/value
A unique feature of cathodic protection in seawater is the formation of calcareous deposits on metal surfaces. Advantageous aspects of these deposits, such as decrease in cathodic current requirement, have been investigated by various authors from various viewpoints. However, very little attention has been paid to the impact of any iron corrosion product films; the present paper contributes useful understanding and explains the importance of the mechanism that controls the operation of the protection system.
Details
Keywords
Lopez Badilla Gustavo, Valdez Salas Benjamin, Schorr Wiener Miguel, Rosas Gonzalez Navor, Tiznado Vazquez Hugo and Soto Herrara Gerardo
The purpose of this paper is to study the indoor corrosion of metals used in the electronics industry, as influenced by climate factors.
Abstract
Purpose
The purpose of this paper is to study the indoor corrosion of metals used in the electronics industry, as influenced by climate factors.
Design/methodology/approach
Corrosivity levels inside industrial plants were evaluated to evaluate the deterioration of metals.
Findings
Relative humidity, temperature, and time of wetness are recorded and related to the corrosion process.
Originality/value
Control of climate factors indoors in industrial plants to reduce and control the corrosion process of metals used in the electronics industry.
Details
Keywords
Mariela Rendón Belmonte, Miguel Martínez Madrid, José Trinidad Pérez-Quiroz, Benjamín Valdez Salas, Erick A. Juarez-Arellano and Miguel Schorr
The purpose of this paper was to characterize the surface of steel reinforcement of concrete under cathodic protection (CP), submerged in seawater, to understand the surface…
Abstract
Purpose
The purpose of this paper was to characterize the surface of steel reinforcement of concrete under cathodic protection (CP), submerged in seawater, to understand the surface changes due to the application of CP and their consequences on cathodic current requirements.
Design/methodology/approach
Reinforced concrete specimens with applied CP were immersed in natural seawater. The experimental methodology included monitoring of corrosion potential (Ecorr); measurement of galvanic current (Igalv), protection potential (Eprotection) and the depolarization potential of steel during the time of exposure; and electrochemical impedance spectroscopy (EIS). The chemical composition of the steel surface was assessed using X-ray diffraction (XRD).
Findings
The application of CP leads to the formation of a deposit on the steel surface that according to XRD results, Pourbaix diagram and physical characteristics, is a protective oxide: magnetite (Fe3O4). This oxide causes a decrease in the corrosion rate and requires application of the protection current. It was found that the surface remained protected even after eight days when the CP system was interrupted.
Research limitations/implications
It is necessary to carry out analysis of the chemical composition of deposits formed on the steel surface, perhaps using X-ray photoelectron spectroscopy, Mössbauer, to verify the presence of the magnetite.
Practical implications
Determination of the main cause of the decrease in current required for protection and deposit formation conditions will enable the design of a CP system to be optimized and economized. At present, the CP design considers only a constant current value for the duration of the protection time.
Originality/value
CP is a technique that has proven effective for the protection of metal structures. However, little attention has been devoted to the surface changes that occur under applied CP and their impact on the electrochemical behavior of the system. This paper describes the phenomena produced at the metal surface and determines kinetic parameters and their consequences on the CP behavior.