Corrosion monitoring of galvanized steel in soil extract solutions by electrochemical impedance spectroscopy

Abstract

The chemical and structural complexity of soils, coupled with their heterogeneity, contributes to the increase in soil aggressiveness, which can in turn result in severe corrosion of underground materials. The understanding of corrosive processes of underground structures is important in aiding the development of methods, as well as in monitoring and maintenance, in an attempt to minimize environmental, social, and economic impacts. In this work, electrochemical impedance spectroscopy (EIS) was used to monitor the corrosive process of galvanized steel when in contact with soil extracts, aimed at evaluating the potentiality of applying electrochemical impedance spectroscopy when monitoring underground structures. To accomplish this, the behavior of the galvanized steel when undergoing corrosion was studied for 105 days, examining the variations in the eletrochemical parameter values obtained through EIS assays over this period. EIS proved to be effective in the study of corrosive processes of galvanized steel when in contact with soil extracts, identifying the different stages of the corrosive process, controlled by mass and/or charge transfer reactions.

Effect of particle size on the electrochemical corrosion behavior of X70 pipeline steel

“…However, in the initial stages of the corrosion process pre to 60 days, the charge transfer resistance R ct increased with the buried time increasing, which can be attributed to the corrosion products are formed and adhere to the electrode's surface . With increasing the buried time, the value of R ct decreased resulting from the detachment of lose products.…”

“…1 West‐East gas pipeline project of underground pipeline engineering mainly uses X70 steel, and about 4000 km long pipeline is buried in the desert of saline soil area in Northwest China . The soil corrosion process of the underground metal structure is influence by many factors, such as water content, chemical composition, environmental pH value, the electrical resistivity, soil type, salinity, noise, porosity and other factors, and the effect of these factors have been investigated by many researches . However, the effect of soil particle size on the electrochemical corrosion behavior of underground metal structure is not fully understood, as corrosion mechanism in soil environment has not been fully uncovered.…”

Corrosion behavior of zinc and copper coated structural steels in soil environments

“…Nyquist and Bode diagrams were recorded after (1, 7, 35, 70 and 105) days of exposure. The study found an increase in resitance was due to predominant mass transfer control followed by a stable resistance [9].…”

“…Effect of coating thickness and soil characteristics were investigated [7]. A comparison with the corrosion data from other parts of the world suggested that soil environment at the chosen test site is strongly corrosive to the tested materials [8][9][10]. Corrosion product formed on copper was studied after 432 hours of immersion in simulated soil environments, which made of bentonite clay mixed with varied contents of sodium chloride, ammonium chloride and sodium sulfide.…”

A Recent Progress of Steel Bar Corrosion Diagnostic Techniques in RC Structures

“…Generally, EIS method is the highly reproducible and powerful method for studying RC systems involved in CSB corrosion mechanism [147], corrosion factors, corrosion evolution process [148], and effectiveness validation of concrete repair scheme [149,150]. For a steel/concrete system, the important parameters including concrete characteristics, interfacial corrosion, surface films, and transport phenomenon, can be provided.…”