Nanometer growth of marine bio-films of different metallic alloys in seawater by electrochemical impedance spectroscopy

Khalid Al-Muhanna,Khaled Habib

doi:10.1063/1.5026305

Abstract

The main purpose of this study was to monitor the growth of the marine bio-film, of micro/macro-organisms, on the surface of different metallic alloys in seawater by electrochemical impedance spectroscopy (EIS). The alloys used in this study were; UNS 1020 carbon steel, stainless steel 304, stainless steel 316L, Sanicro 28, Cu–Ni 70–30, Hastelloy G-30, and titanium. The EIS was used to measure the A.C. Impedance (Z) and the double layer capacitance (Cdl) of the formed bio-film in seawater on a frequent basis. The total exposure time of the tests ranged between 90 days to 180 days. The visual inspection of the tested samples showed a bio-film formation on the surface of these samples. The microbiologically influenced (induced) corrosion (MIC) was observed only on the carbon steel. Monitoring the growth of the bio-film formation was accomplished by the EIS during the 90-180 days exposure of the tested samples. A gradual monitoring of the growth of the bio-film formation was achieved by mathematically correlating the obtained the A.C. Impedance (Z) and the double layer capacitance (Cdl) of the bio-film to the thickness of the bio-film formation. The advantage of EIS is a non-invasive technique with a sensing (spatial) resolution in a nanometer scale in a comparison to other techniques of monitoring the growth of bio-films on metallic alloys in aqueous solutions.

Highlights

It has been widely known that marine bio-fouling of metal surfaces in contact with seawater is the main cause of several technical problems and economic loss in industry
An example of an electrochemical impedance spectra of the stainless steel 304 in seawater is given in Figure 1 at different periods of time
The following conclusions have been drawn from the present investigation: 1. The electrochemical impedance spectroscopy (EIS) has been successfully applied to real-time monitoring the growth (L) of the biofilm of several metallic alloys in sweater, leading to the microbiologically induced corrosion (MIC) in solely the carbon steel samples during 90 days of exposure

Summary

Introduction

It has been widely known that marine bio-fouling of metal surfaces in contact with seawater is the main cause of several technical problems and economic loss in industry. It has been reported that a total of 84 species of fouling organisms belonging to 69 genera, 49 families, and 10 phyla were recorded over the entire year dependent on the temperature of the seawater.. It has been reported that a total of 84 species of fouling organisms belonging to 69 genera, 49 families, and 10 phyla were recorded over the entire year dependent on the temperature of the seawater.1 The growth of this community usually interferes with the efficient use of the surfaces. It is known that marine micro fouling reduces heat transfer coefficient in heat exchange systems by as much as 40% besides causing what is known as microbiologically induced corrosion (MIC).. The growth of the marine biofouling film at metal–solution interfaces would control the corrosivity of the submerged metals in seawater

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Results

Conclusion