Electrocorrosion And Protection Of Metals

Electrocorrosion, the corrosion of metallic constructions by external currents, is the most significant factor in conductive aggressive environments. Corrosion of underground and underwater metal constructions by stray currents has been comprehensively studied in the past decades and is considered here only in the form of a review. The primary attention is on corrosion, by external anodic (mainly) and cathodic currents, of metal constructions in the highly aggressive environments typical for electrochemical plants, where penetration of the external currents (leakage currents) from the electrolytic baths into metal constructions is unavoidable. A new approach to the problem of electrocorrosion protection of passive structural metals is considered in this book, keeping the metals attacked by external currents in the boundaries of their passive field. The systems, developed in accordance with this approach, are based on the modification of existing and elaboration of new methods of electrocorrosion protection. These systems take into account corrosion and electrochemical characteristics of the aggressive media (redox potential, conductivity etc.) and of the passive metal (corrosion and activation potentials, current density in a passive state, etc) as well as the sizes and distribution character of the external currents. The book covers analysis of leakage current distributions in electrochemical plants, their influence, methods to estimate corrosion stability of metallic structures subject to external currents and presents many concrete examples of the successful introduction of corrosion protection systems in operating plants. A new approach to protection from electrocorrosion, taking into account the passive state of the metal in aggressive media Newly developed and modifications of well known methods of electrocorrosion protection are presented. Systematized data on electrocorrosion and protection of metals, especially in electrochemical plants, allow corrosion engineers, researchers and personnel maintaining the equipment of electrochemical plants to analyze the corrosion state of metallic equipment and prevent electrocorrosion.

Electrocorrosion and Protection of Metals, Second Edition, compiles theoretical and practical information, outlines the specific problem, and presents the available solutions related to corrosion by external currents. Basic data on the behavior of different metals under the attack of anodic, cathodic, direct and alternating currents is considered, as are the problems of electrocorrosion—from the identification of corrosion damage and detection of the external current sources, to the selection of optimal means and methods of mitigation, monitoring and protection of different metallic structures and structures of reinforced concrete. This book includes comprehensive information and provides necessary links to more detailed, original sources, thus enabling users to solve either general or particular problems of electrocorrosion and protection of metals. Provides a comprehensive listing of all possible sources of external currents which attack metallic equipment, piping and other metallic structures Outlines the sources of corrosion damage for fast and reliable analysis Provides technical examples and case studies related to electrocorrosion Presents new data and methods of electrocorrosion control and monitoring using computerized techniques and technologies Includes original methods—only considered in this publication—of metals protection against electrocorrosion

Introduction and Scope-During the last few decades, an enormous effort has been made to understand corrosion phenomena and their mechanisms, and to elucidate the causes that dramatically influence the service lifetime of metal materials. The performance of metal materials in aggressive environments is critical for a sustainable society. The failure of the material in service impacts the economy, the environment, health, and society. In this regard, corrosion-based economic losses due to maintenance, repair, and the replacement of existing structures and infrastructure account for up to 4% of gross domestic product (GDP) in well developed countries. One of the biggest issues in corrosion engineering is estimating service lifetime. Corrosion prediction has become very difficult, as there is no direct correlation with service lifetime and experimental lab results, usually as a result of discrepancies between accelerated testing and real corrosion processes. It is of major interest to forecast the impact of corrosion-based losses on society and the global economy, since existing structures and infrastructure are becoming old, and crucial decisions now need to be made to replace them. On the other hand, environmental protocols seek to reduce greenhouse effects. Therefore, low emission policies, in force, establish regulations for the next generation of materials and technologies. Advanced technologies and emergent materials will enable us to get through the next century. Great advances are currently in progress for the development of corrosion-resistant metal materials for different sectors, such as energy, transport, construction, and health. This Special Issue on the corrosion and protection of metals is focused on current trends in corrosion science, engineering, and technology, ranging from fundamental to applied research, thus covering subjects related to corrosion mechanisms and modelling, protection and inhibition processes, and mitigation strategies.

Covering the essential aspects of the corrosion behavior of metals in aqueous environments, this book is designed with the flexibility needed for use in courses for upper-level undergraduate and graduate students, for concentrated courses in industry, for individual study, and as a reference book.

This comprehensive handbook covers all aspects of cathodic protection in terms of both practice and theory.