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The rust layer formed on carbon steel exposed to natural marine and urban-continental envi-ronments for up to 50 years was studied. Mineralogical phase composition of the rust layer was evaluated by X-ray diffraction (XRD), akaganeite, goethite, lepidocrocite, magnetite, and amorphous phases were identified. Morphological characterization of the specimens was performed using scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) microanalysis. Mechanical stress generated during the formation of the oxide causes exfoliation-induced breakout of the rust layer. Volume variation generated by structural transformations and crystallization pressure (Δp) of the crystalline phases were analyzed to assess the mechanical stress on the rust and a linear relationship was found between the molar volume expansion ratio coefficient (α) and the Δp param-eter. The highest Δp was yielded by goethite (374.99 MPa), while akaganeite presented the highest α value (3.29)., D.M. Bastidas, J. Ress, U. Martin and J. Bosch acknowledge funding from The University of Akron, Fellowship Program FRC-207367.

The corrosion behavior of the sulphuric-anodized AA2099 using two different current densities, 0.19 or 1.0 A·cm, with two different sealing treatments in HO and 6 wt.% NaCrO at 95 °C was studied in 3.5 wt.% NaCl and 10 vol.% HSO solutions. The AA2099 is widely used in aeronautical applications, thus it is essential to present good corrosion performance in chloride and acid rain environments. The surface morphology of the anodized film was characterized by scanning electron microscopy (SEM), the electrochemical corrosion behavior was studied using electrochemical impedance (EIS), and finally characterization of the surface chemical composition was revealed by X-ray photoelectron spectroscopy (XPS). It was found the 6 wt.% NaCrO sealing treatment imparts a more homogeneous and compact passive layer, and tends to increase the charge transfer resistance, thus improving the corrosion behavior of the anodized AA2099., Efecto del tratamiento de sellado en el comportamiento frente a corrosión de la aleación anodizada de aluminio-litio AA2099. El comportamiento frente a corrosión de la aleación de aluminio AA2099 anodizado en solución de H2SO4, aplicando dos densidades de corriente diferentes, 0,19 o 1,0 A·cm−2, con dos tratamientos de sellado diferentes en H2O y en Na2Cr2O7 (6% peso) a 95 °C, se ha estudiado en disoluciones de NaCl (3,5% peso) y de H2SO4 (10% vol). La aleación AA2099 se usa ampliamente en aplicaciones aeronáuticas, por tanto, se requiere que presente un buen comportamiento frente a la corrosión en ambientes de cloruro y lluvia ácida. La morfología de la superficie de la película anodizada se caracterizó por microscopía electrónica de barrido (MEB), se estudió el comportamiento frente a corrosión electroquímica empleando la impedancia electroquí-mica (EIS), y finalmente la caracterización de la composición química de la superficie se reveló por espectros-copía de fotoelectrones de rayos X (XPS). Se encontró que el tratamiento de sellado con Na2Cr2O7 (6% peso), genera una capa pasiva más homogénea y compacta, y tiende a aumentar la resistencia a la transferencia de carga, mejorando así el comportamiento frente a corrosión del AA2099 anodizado., The authors would like to thank the Mexican National Council for Science and Technology (CONACYT) for the support provided for the devel-opment of the projects CB 253272 and A1-S-8882, the UANL-CA-316 working group and Universidad Autónoma de Nuevo León (UANL) for the facili-ties given to develop this investigation. U. Martin, J. Ress and D.M. Bastidas acknowledge funding from Firestone Research Grant 639430 and The University of Akron.

Corrosion of reinforced concrete structures is nowadays one of the major concerns on the durability and serviceability of buildings and constructions. Corrosion management and monitoring of infrastructure and civil engineering structures are required to guarantee their lifetime in service. Current society demands for new materials; diagnosis techniques and computational modeling then can contribute to increase corrosion resistance, thus improving safety and extending the service lifetime of reinforced concrete structures. Sustainability of reinforced concrete structure is crucial for better social development because of the importance of structural safety, preservation of environment, and economy. In developed countries, corrosion economic losses due to maintenance, repair, and replacement of existing structures and infrastructure account for up to 4% gross domestic product (GDP). It is worth to note that production of new materials not only is costly but also requires a large amount of energy consumption, which dramatically influences greenhouse effect because of CO2 emissions., As guest editors, we would like to especially thank Jonathan Wood, review operations specialist, for his support and active role in the publication. We are also grateful to the entire staff of the Frontiers in Materials Editorial Office for the precious collaboration.

The Cathedral of León is one of the principal Gothic cathedrals in Spain, renowned for its impressive stained-glass windows. Since the beginning of its construction in the 13th century, it has suffered structural problems which have kept it under constant construction and restoration works. An extensive restoration carried out in the late 19th century rebuilt many parts of the building, including the transept and the south façade. To add stability to each course, cut stones were joined using metal brackets; these reinforcements are usually carried out using iron brackets fixed by molten lead, but in this case the materials used were bronze brackets and molten sulphur. The corrosion of these brackets is causing tension, resulting in cracks and fractures in the stones. This article summarises the results of a research project carried out by the Consejo Superior de Investigaciones Científicas (CSIC) and the Instituto del Patrimonio Cultural de España (IPCE) aimed at understanding the causes and mechanisms of this corrosion process in order to establish the scientific basis for the conservation works. Samples of brackets and corrosion products from the south gable have been studied and the metal characterised by means of X-ray fluorescence (XRF) and Scanning electron microscope (SEM). Corrosion products have been identified using SEM-EDX. Laboratory tests have been carried out to simulate the initial steps of the corrosion processes. Results have shown that the brackets are made of cast bronze, presenting a large amount of pores and inclusions. Thick corrosion crusts are present in the interface between the bronze and the sulphur, with a layered structure of copper sulphides (covellite (CuS)) and sulphates, mainly of copper (brochantite, Cu4(SO)4(OH)6; antlerite, Cu3(SO4)(OH)4). Laboratory tests have demonstrated that covellite forms immediately from the direct reaction of copper with molten sulphur. This is a spontaneous reaction that continues over time as long as copper and sulphur are present. In spite of the great thickness of the covellite layers, up to 2 cm at some points, the formation of covellite does not involve an increase in volume, so it cannot explain the fractures in the stones. However, when water and oxygen reach the covellite through pores and cracks in the stone, different sulphates are formed and sulphuric acid, which attacks the metallic copper, is released. The formation of sulphates causes an increase in the volume of corrosion products, and this is responsible for the mechanical damage to the stones. Our work has demonstrated that the formation of sulphates by the reaction of covellite with oxygen and water is the controlling step of the degradation process. This has significant implications for conservation: while the degradation process cannot be completely arrested, it can be limited by reducing the water uptake of the stones and the entry of water through cracks and joints in the masonry.

En este libro se presentan trabajos de investigación científico-técnica, así como casos prácticos de aplicación de armaduras de acero inoxidable, realizados por grupos de investigación de reconocido prestigio. Los capítulos incluidos en esta obra, son el fruto de los resultados de investigación obtenidos en proyectos competitivos de investigación, tanto fundamental como aplicada. La utilización del acero inoxidable, de los tipos dúplex y austenítico, como refuerzos corrugados en estructuras de hormigón armado, está adquiriendo una gran atención en la actualidad. Esto se justifica debido a la mayor durabilidad de la estructura en servicio, en gran medida debido al mejor comportamiento frente a la corrosión de las armaduras de acero inoxidable. La aplicación del acero inoxidable en estructuras de hormigón armado, presagia un mayor tiempo de vida útil en servicio y por tanto un incremento de las garantías que desde la dirección de construcción de la estructura se pueden ofrecer. Los diferentes estudios realizados de las armaduras de acero inoxidable demuestran un mejor comportamiento frente a la corrosión que las armaduras tradicionalmente utilizadas de acero al carbono (habitualmente B500SD). Además satisfacen los requisitos mecánicos y de resistencia al fuego de forma óptima., Autores: Acosta, P. Matres, V. Alonso, M.C. Medina, E Álvarez, S.M. Múñoz, S Bastidas, D.M. Nóvoa, X. R. Bautista, A. Pachón, A. Belzunce, F. J. Paredes, E. C. Bonaste, V. Peiró, L. M. Fajardo, S. Picón, J. M. Fernández, J. J. Rodríguez, C. Franssen, J. M. Salmerón, A. Fuentes, J. R. Salvador, M. Fullea, J. Sánchez, J.

4 páginas, 2 figuras. Ed. Miguel Ángel Rogerio Candelera y Cesáreo Sáiz Jiménez. Primera Reunión de la Red de Ciencia y Tecnología para la Conservación del Patrimonio (Madrid, 28-29 de junio de 2011)., La corrosión, es decir, la reacción química del metal con el medio en que se encuentra, es la principal causa de degradación del patrimonio cultural metálico. La naturaleza y estructura del material metálico, y el medio en el que se encuentra (sea el medio atmosférico exterior o interior de un museo o vitrina; el agua del mar o la tierra en los objetos sumergidos o enterrados; o incluso componentes de otra naturaleza que forman parte del propio objeto) condiciona los mecanismos y velocidad de deterioro. Es por lo tanto fundamental, si queremos asegurar correcta conservación de este patrimonio metálico, conocer los mecanismos por los que se produce este deterioro y desarrollar metodologías y estrategias para su protección, especialmente adaptadas a las características y necesidades peculiares de este tipo de objetos.

14 p.-10 fig.-7 tab., This work analyzes the premature corrosion failure of a welded AISI 304 stainless steel (SS) pipe network in well water (WW) for 6 months. Laboratory tests were performed to analyze the corrosion behavior and to identify and distinguish the genera of bacteria. Pipe specimens were analyzed using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy,open circuit potential, cyclic potentiodynamic polarization, and electrochemical impedance spectroscopy. Physicochemical properties of WW in the AISI 304 SS pipe presented a positive Langelier saturation index, indicating the formation of corrosion scales. In welded 304 austenitic SS, the chromium depletion both in HAZ and in weld-metal leads to preferential anodic dissolution. The biofilm electrochemical activity produces oxygen concentration cells and the acid metabolic products induce preferential MIC, thus leading to pit formation on the HAZ of the weld. Biodiversity analysis of bacteria by next generation sequencing was carried out in corroded AISI 304 SS pipes and different genera of bacteria were identified., JR and DMB acknowledge funding from The University of Akron, Fellowship Program FRC-207367.