Electrochemistry And Corrosion Science
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Corrosion is a dangerous and extremely costly problem. Because of it, buildings and bridges can collapse, oil pipelines break, chemical plants leak, and bathrooms flood. It affects all classes of materials and is a key concern in virtually all technologies. MSEN faculty work on all aspects of corrosion science and engineering. Specific topics include the physicochemical basis of corrosion and kinetics; passivity; localized corrosion; corrosion protection including surface treatments and coatings; anode behavior; high-temperature corrosion and oxidation; methods for the study of corrosion including spectroscopy and electrochemical techniques and scanning probe microscopies; numerical simulations, computational chemistry, and mathematical modeling as applied to corrosion.
We are experts in electrochemistry and corrosion science. Established by Professor David W. Shoesmith and led by Professor James J. Noël, the group is investigating various industrial corrosion and environmental contamination problems encompassing a range of detailed electrochemical, chemical, metallurgical and transport reactions that make up complex materials and corrosion processes. Besides novel experimental techniques, the group uses computational modelling approaches from detailed deterministic process models to statistical/probabilistic and environmental performance assessment models. Our primary research areas are:
The group has a unique approach to investigating corrosion and material degradation processes. Use of most advanced electrochemical techniques (high precision potentiostats in conjunction with FRA, the Multichannel Microelectrode Analyzer, and Precision Resistance Measurements systems), together with state-of-the-art surface analysis techniques (XPS, Raman, TOF-SIMS spectroscopies, SEM/EDX to mention a few) allows in-depth investigation of the material degradation in an extensive range of environments.
The International Union of Pure and Applied Chemistry (IUPAC) and European Federation of Corrosion (EFC) define corrosion as an irreversible interfacial reaction of a material with its environment which results in its consumption or dissolution, often resulting in effects detrimental to the usage of the material considered [...].
Combining electrochemistry, electron microscopy and diffraction to better understand the influence of process formed nano and microstructure on corrosion of 3D printed stainless steel: \"Microstructure and Corrosion Resistance of Laser Additively Manufactured 316L Stainless Steel\"
Corrosion is the process that results in the deterioration of the performance of a material the result of which is corrosion damage. A physicochemical interaction leading to a significant deterioration of the functional properties of either a material, or the environment with which it has interacted, or both of these. Corrosion damage to materials can be caused by a wide variety of environments. The overall corrosion process necessarily involves at least two simultaneous reactions: an oxidation (or anodic) reaction and a reduction (or cathodic reaction), which are coupled through the exchange of electrons and are therefore known as electrochemical reactions. Passivity is caused by the solid-state electrochemical oxidation of a metallic substrate, under the correct conditions of potential and pH, to a solid species that is largely stable to dissolution. The four main methods for controlling the corrosion of a material or component are: (a) materials selection, (b) environmental modification, (c) electrochemical control and (d) application of a protective coating.
Compared with other corrosive media, artificial soil is characterized by non-flowing, heterogeneity, seasonality, and regionalism. Metal corrosion in artificial soil is caused by electrochemical action between metal and the artificial soil. Apart from inborn factors, metal corrosion speed is determined by the surrounding environment. A variety of factors affect metal corrosion separately or in a combined way, such as moisture content, oxygen content, total soluble salt content, contents of anion and metal ion, pH value, soil microorganism30,31,32.
Previous research finds that the effect of soil pH on soil erosion is obvious. With pH fluctuating, the corrosion rate of metal materials is obvious influence. The pH value of soil is closely related to region and microorganisms in soil45,46,47. In general, the influence of soil pH on the corrosion of metal materials in slightly alkaline soil is unapparent. The soil in three kinds of railway slope is alkaline, so the influence of pH on metal net corrosion is weak.
The School of Computing and Information Sciences (SCIS) is committed to providing unique capabilities in computer science and computational thinking to develop innovative solutions to today's complex problems.
The Corrosion and Infrastructure Materials Durability research laboratory addresses durability concerns of civil infrastructure based on applied electrochemistry in corrosion science and engineering, electrochemical diagnostic techniques, and structural materials and design.
Corrosion in carbonated concrete is an example of corrosion in dense porous media of tremendous socio-economic and scientific relevance. The widespread research endeavors to develop novel, environmentally friendly cements raise questions regarding their ability to protect the embedded steel from corrosion. Here, we propose a fundamentally new approach to explain the scientific mechanism of corrosion kinetics in dense porous media. The main strength of our model lies in its simplicity and in combining the capillary condensation theory with electrochemistry. This reveals that capillary condensation in the pore structure defines the electrochemically active steel surface, whose variability upon changes in exposure relative humidity is accountable for the wide variability in measured corrosion rates. We performed experiments that quantify this effect and find good agreement with the theory. Our findings are essential to devise predictive models for the corrosion performance, needed to guarantee the safety and sustainability of traditional and future cements.
The question of corrosion rates in carbonated concrete is, after having been addressed for over half a century, currently receiving more and more attention. This is because of the increasing market share and promotion of blended cements as alternatives for the traditional Portland cement15,16,17. These modern cement types are claimed to be more environmentally friendly, thanks to the reduced energy consumption as well as reduced emissions of greenhouse gases such as carbon dioxide during production. Their ability, however, to protect the embedded reinforcing steel from corrosion is still under debate. For holistic assessments of the sustainability of these modern materials, the long-term corrosion performance is crucial. Considering the time to corrosion initiation alone will not permit realistic assessments, because some of the modern binders are known to carbonate substantially faster than Portland cement18,19,20; thus, it is important to also consider the corrosion propagation stage, which requires the knowledge and prediction of corrosion rates. Finally, the continuously increasing diversity in physical and chemical properties of modern cement types imposes an urgent need for a mechanistic model for the prediction of corrosion rates in carbonated concrete21.
Effect of relative humidity (RH) on corrosion rate and other electrochemical parameters in carbonated mortar. (A) Sample geometry and instrumentation with embedded steel wires and sensors (Supplementary Figures 1 and 2); (B) Experimental procedure including initial carbonation followed by exposure at different RH and corresponding electrochemical measurements; (C) Cathodic limiting current density (ilim) and corrosion rate (icorr) for the different studied systems (water/binder ratios and cement types) as a function of RH (Supplementary Table 1); (D) Electrical mortar resistivity as a function of material parameters and RH (Supplementary Table 1).
There exists a relationship between the corrosion rate and the electrical resistivity of the mortar as shown in Fig. 2A. This is a common form of representing the data24,25,26,27,28,29,30, which may ultimately be traced to the widespread hypothesis of a causality between these two parameters. Several authors24,25,26,27,28,29 suggested that the ohmic resistance of the mortar is the rate-limiting step in the corrosion process, that is, the ion transport between anodic and cathodic sites (through the pore system of the mortar) limiting the corrosion current. However, this mechanistic explanation has been criticized on an experimental basis, pointing out that ohmic control is in contrast with the correlation found between corrosion rate and corrosion potential30,31. Additionally, ohmic control is also unlikely from a theoretical viewpoint, because the uniform type of corrosion, typically observed in carbonated concrete, means that both the anodic and cathodic reactions occur homogeneously and time-variably distributed over the steel surface, forming micro-cells with negligibly small ohmic resistance due to the microscopic distance between the neighboring reaction sites32,33,34.
Correlation between corrosion rate (icorr) and other electrochemical parameters as well as illustration of the oxygen paradox in dense porous media. (A) Traditional representation of icorr vs. electrical resistivity of concrete that may erroneously be interpreted as proof for a causality; (B) The cathodic limiting current density has been experimentally measured as increasing with RH (black series: symbols = mean values, whiskers = standard deviations). On the contrary, in the literature, oxygen has always been considered as decreasing with RH, because of argumentations only based on the purely physical diffusion behaviour. An example taken from the literature37 is reported in the figure, in order to show the completely opposite trend between what has been measured (black series) and what has been calculated in37 (blue series); (C) Close correlation between icorr and ilim. Such correlation has never been shown before and it suggests there is the same mechanism controlling the two electrochemical processes. 59ce067264