Investigation of agar as a soil analogue for corrosion studies

Spark, A; Cole, Ivan; Law, David W.; Marney, Donavan; Ward, Liam

doi:10.1002/maco.201508312

Cited by 14 publications

(13 citation statements)

References 26 publications

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“…For corrosion studies, a semi-solid agar medium was used to replicate soil conditions for microbialinfluenced attack of underground pipelines [23,24]. In the field of cultural heritage, a gel electrolyte was proposed to perform corrosion studies on metallic artefacts of archeological and historical interest [25,26].…”

Section: Introductionmentioning

confidence: 99%

Non-Destructive Electrochemical Testing for Stainless-Steel Components with Complex Geometry Using Innovative Gel Electrolytes

Monrrabal

Ramírez-Barat²,

Bautista

et al. 2018

Metals

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Corrosion can be a problem for stainless steels in chloride-containing or other aggressive environments, especially when they are formed as components with complex shapes. Monitoring the corrosion performance of the stainless steels during their in-service life is not always an easy task. Traditional electrochemical cells can be difficult to adapt to complex surfaces, and undesired crevices or liquid electrolyte leaks can occur. In the presented work, the possible use of non-destructive techniques with innovative gel electrolytes was investigated using portable cells. The electrolytes were based on agar (used as a gelling agent with ionic conductivity), glycerol (a plasticizer that improves adaptability to complex surfaces), and NaCl or KClO 4 salts (which improve the conductivity and control the aggression of the tests). X-ray photoelectron spectroscopy (XPS) and Mott-Schottky analysis were carried out to obtain information about the influence of the electrolyte on the passive layer. The oxygen concentration and conductivity in the gels with various glycerol contents were compared to those in liquid electrolytes. Electrochemical impedance spectroscopy (EIS) measurements were carried out in liquids and gels. The performance of the gel cell on a stainless-steel component with a weld and complex shape was checked. The variation in the sensitivity of gels with and without chlorides to identify corrosion-susceptible regions was tested.

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Section: Introductionmentioning

confidence: 99%

Non-Destructive Electrochemical Testing for Stainless-Steel Components with Complex Geometry Using Innovative Gel Electrolytes

Monrrabal

Ramírez-Barat²,

Bautista

et al. 2018

Metals

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“…The compactness of corrosion product layers strongly depended on the soil PSD. Thus, the loose, incomplete, product layer formed on the X70 steel surface during burial in the GG environment would accelerate steel corrosion, and let aggressive ions in soil infiltrate crevices and react with the substrate, and then cause severe corrosion . However, due to the effect of soil PSD, the corrosion product film formed in the GG environment is less intact and offers less protection for the substrate, as the SEM morphology observations showed.…”

Section: Resultsmentioning

confidence: 99%

Role of typical soil particle‐size distributions on the long‐term corrosion behavior of pipeline steel

Han

Hou

et al. 2016

Materials & Corrosion

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The electrochemical behavior of X70 pipeline steel in a 1.5 wt% NaCl sandy soil environment with two typical particle size distributions (PSD), continuous gradation (CG), and gap gradation (GG) was investigated using electrochemical measurements, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results showed that, as the burial time increased, the corrosion rate of X70 pipeline steel increased in the initial corrosion stage, decreased at an intermediate stage, and then increased in the final stage in these two typical soil PSD environments. However, compared with the soil PSD pertaining to the CG environment, the corrosion rate of steel increased significantly in the GG environment, as evinced by the severe corrosion spots observed on the steel surface, attributed to the fact that, in the soil PSD for the GG environment, both the extent of liquid dispersion, and the number of galvanic cells increased, accelerating the cathodic step, i.e., oxygen-reduction reaction in the three-phase boundary (TPB) zone, and anodic step, i.e., the metal dissolution stage, of the X70 pipeline steel corrosion process, respectively. Both the anodic and cathodic processes were activation controlled. Thus, the corrosion of X70 pipeline steel was considerably dependent on the soil PSD in sandy soil environments. Materials and Corrosion 2016, 67, No. 5 Role of soil PSD on the corrosion behavior of steel Figure 15. SEM micrographs of the surface morphologies of X70 pipeline steel in (a) CG PSD soil; (b) GG PSD soil www.matcorr.com

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“…Hot rolled HA1 carbon steel sheet 1 mm thick was cut into 25 mm 2 coupons and polished to a final finish with 1 μm diamond paste. The composition and polishing process for the steel is given in previous publications. , Immediately prior to setting up an experiment, the exposed face of the coupons was sterilized with 30 min exposure to UV.…”

Section: Methodsmentioning

confidence: 99%

“…It is also difficult to obtain reproducible results from soil samples. As a consequence of these limitations, agar has been investigated as a soil analogue to enable fundamental corrosion studies where the physical characteristics of soil as well as the chemical characteristics are incorporated in the system while also allowing for control of the system . Previous studies have optimized this system with semisolid agar and investigated the effect of varying concentrations of peptide nutrients on steel .…”

Section: Introductionmentioning

confidence: 99%

Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion

Spark

Law

Ward

et al. 2017

Environ. Sci. Technol.

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Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.

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Investigation of agar as a soil analogue for corrosion studies

Cited by 14 publications

References 26 publications

Non-Destructive Electrochemical Testing for Stainless-Steel Components with Complex Geometry Using Innovative Gel Electrolytes

Non-Destructive Electrochemical Testing for Stainless-Steel Components with Complex Geometry Using Innovative Gel Electrolytes

Role of typical soil particle‐size distributions on the long‐term corrosion behavior of pipeline steel

Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion

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