Investigating atmospheric corrosion behavior of carbon steel in coastal regions of Mauritius using Raman Spectroscopy

Abstract

Low carbon steel was exposed at two sites in Mauritius, namely Port Louis and Belle Mare. The site at Port Louis is basically an industrial marine one whereas the one at Belle Mare is a purely marine site. Though the corrosion loss trend at both sites follow the power law, the corrosion loss at Port Louis was found to be higher than that at Belle Mare. This study has been performed to investigate the surface characteristics of the rust layers of the samples exposed at the two sites, through Raman spectroscopy and SEM, so as to get a better insight into the mechanism of the atmospheric corrosion process. For Port Louis, it was observed that there was not much change in the corrosion products in the rust layer over the 3 years period. The structure was less compact than that at Belle Mare with the presence of lepidocrocite and akaganeite as commonly observed corrosion products. The corrosion rate at Port Louis is, therefore, expected to follow the same trend over the long term. For Belle Mare, the corrosion products changed significantly after 3 years of exposure. Though lepidocrocite and akaganeite were observed on the surface after 0.2 years of exposure, magnetite was the most probable corrosion product in the more compact rust layer after 3 years of exposure. This compactness of the rust layer is expected to have reduced the corrosion rate as compared to that of Port Louis. Significant changes in the corrosion rate at Belle Mare are, therefore, expected over the medium and the long term.

The Microstructure, Proteomics and Crystallization of the Limpet Teeth

“…To observe the nanoscale ultrastructure of the teeth, transmission electron microscopy (TEM) was conducted. The fresh teeth were fixed in 2.5% glutaraldehyde for 2 h followed by 1% osmic acid for 2 h. They were dehydrated in serial ethanol solutions (50,70,80,90, and 100%), followed by 1:1 ethanol:acetone, and finally 100% acetone. Samples were then embedded in Spurrs resin and polymerized at 60°C for 48 h. Subsequently, they were sectioned on a microtome (Leica EM UC6) to produce 80 nm thin transverse sections.…”

Corrosión atmosférica acelerada en una fundición gris ASTM A48

“…Algunos de ellos se han concentrado en caracterizar ambientes de corrosión [1] y otros en evaluar la resistencia a la corrosión atmosférica marina en aceros [2,3] y fundiciones [4][5][6]. La realización de trabajos como estos tiene una desventaja en común y es que para su realización se requiere de años, por ello algunos autores y en particular este equipo de trabajo, se han concentrado en buscar la forma de reducir estos tiempos a través de la realización de experiencias de corrosión acelerada [7][8][9][10][11][12][13][14][15][16], que tras poco tiempo (días) y en laboratorio puedan generar resultados concordantes con los obtenidos en años de exposición a la intemperie.…”

Effect of aeration on Tafelian behavior of the carbon steel corrosion in acid sulfate medium

“…This leads to increase costs for maintenance, repair and in many cases puts in risk of failure the installed infrastructure during the operation. For this reason, it has been of great interest to study the conditions and environments both external and internal to which the steel is exposed, in order to obtain information to prevent critical damages, to identify the effects or products of corrosion and to be able to predict behaviors for both short and long-term [1,2]. Among the sources of corrosion in which LCS are exposed the media containing sulfates appears [3]; chlorides, sulfur [1], salts, carbonates, particulate matter [4].…”

“…This oxide layer has been of great interest in the advance investigations on the degradation of carbon steels [2,5,6]. It has been sought to identify and characterize the complex composition of the layer.…”