Marine Atmospheric Corrosion of Carbon Steel: A Review

Abstract

The atmospheric corrosion of carbon steel is an extensive topic that has been studied over the years by many researchers. However, until relatively recently, surprisingly little attention has been paid to the action of marine chlorides. Corrosion in coastal regions is a particularly relevant issue due the latter’s great importance to human society. About half of the world’s population lives in coastal regions and the industrialisation of developing countries tends to concentrate production plants close to the sea. Until the start of the 21st century, research on the basic mechanisms of rust formation in Cl−-rich atmospheres was limited to just a small number of studies. However, in recent years, scientific understanding of marine atmospheric corrosion has advanced greatly, and in the authors’ opinion a sufficient body of knowledge has been built up in published scientific papers to warrant an up-to-date review of the current state-of-the-art and to assess what issues still need to be addressed. That is the purpose of the present review. After a preliminary section devoted to basic concepts on atmospheric corrosion, the marine atmosphere, and experimentation on marine atmospheric corrosion, the paper addresses key aspects such as the most significant corrosion products, the characteristics of the rust layers formed, and the mechanisms of steel corrosion in marine atmospheres. Special attention is then paid to important matters such as coastal-industrial atmospheres and long-term behaviour of carbon steel exposed to marine atmospheres. The work ends with a section dedicated to issues pending, noting a series of questions in relation with which greater research efforts would seem to be necessary.

Characterization of Corrosion Products on Weathering Steel Bridges Influenced by Chloride Deposition

“…It had the greatest impact on steel corrosion rate in the Czech Republic between 1970 and 1980. The subsequent introduction of desulphurization units brought a substantial reduction of SO2 concentration in the atmosphere and the corrosion losses of carbon steel in the Czech Republic, current values stay below 10 µg/m 3 [6][7][8], see Figure 1. Due to the notable decline in SO2 concentrations, chlorine ions (Cl − ) originating from de-icing salt used for winter road maintenance have become much more important factors of corrosive damage.…”

“…The action of the chlorides leads to the formation of a corrosion layer at an increased rate, the resulting layer being thick and layered with numerous pores limiting the protective function of the corrosion layer on the surface of the weathering steel [8,9]. In coastal areas, the deposition rate of chlorides ranges from 250 mg·m −2 ·day −1 to 2000 mg·m −2 ·day −1 , which is mainly sea salt aerosol in the air [8]. In inland areas, chlorides are spreading from de-icing chemicals used during the winter.…”

“…Increased chloride Due to the notable decline in SO 2 concentrations, chlorine ions (Cl − ) originating from de-icing salt used for winter road maintenance have become much more important factors of corrosive damage. The action of the chlorides leads to the formation of a corrosion layer at an increased rate, the resulting layer being thick and layered with numerous pores limiting the protective function of the corrosion layer on the surface of the weathering steel [8,9]. In coastal areas, the deposition rate of chlorides ranges from 250 mg·m −2 ·day −1 to 2000 mg·m −2 ·day −1 , which is mainly sea salt aerosol in the air [8].…”

Using an Engineered Galvanic Redox System to Generate Positive Surface Potentials that Promote Osteogenic Functions

“…17–19 In this system, iron (Fe) acts as an anode, and the numerous interstitial doped surface carbon (C) atoms act as nanoscale cathodic sites. The electron flow from the anode (Fe) to the cathode (C) leads to an increased electron density and a higher negative electric potential on the anode than on the cathodic sites.…”

“…The electron flow from the anode (Fe) to the cathode (C) leads to an increased electron density and a higher negative electric potential on the anode than on the cathodic sites. 17–19 To harness this phenomenon, we sought to delicately engineer a similar nanoscale galvanic redox system that generates a positive surface potential (SP) on a biomedical metal material, and as a result, promotes bone growth and osseointegration of a metal implant.…”