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Angst UM, Rossi E, Boschmann Käthler C, Mannes D, Trtik P, Elsener B, Zhou Z, Strobl M. Chloride-induced corrosion of steel in concrete-insights from bimodal neutron and X-ray microtomography combined with ex-situ microscopy. Mater Struct 2024; 57:56. [PMID: 38601013 PMCID: PMC11001691 DOI: 10.1617/s11527-024-02337-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 03/19/2024] [Indexed: 04/12/2024]
Abstract
The steel-concrete interface (SCI) is known to play a major role in corrosion of steel in concrete, but a fundamental understanding is still lacking. One reason is that concrete's opacity complicates the study of internal processes. Here, we report on the application of bimodal X-ray and neutron microtomography as in-situ imaging techniques to elucidate the mechanism of steel corrosion in concrete. The study demonstrates that the segmentation of the specimen components of relevance-steel, cementitious matrix, aggregates, voids, corrosion products-obtained through bimodal X-ray and neutron imaging is more reliable than that based on the results of each of the two techniques separately. Further, we suggest the combination of tomographic in-situ imaging with ex-situ SEM analysis of targeted sections, selected based on the segmented tomograms. These in-situ and ex-situ characterization techniques were applied to study localized corrosion in a very early stage under laboratory chloride-exposure conditions, using reinforced concrete cores retrieved from a concrete bridge. Several interesting observations were made. First, the acquired images revealed the formation of several corrosion sites close to each other. Second, the morphology of the corrosion pits was relatively shallow. Finally, only about half of the total 31 corrosion initiation spots were in close proximity to interfacial macroscopic air voids, and > 90% of the more than 160 interfacial macroscopic air voids were free from corrosion. The findings have implications for the mechanistic understanding of corrosion of steel in concrete and suggest that multimodal in-situ imaging is a valuable technique for further related studies. Supplementary Information The online version contains supplementary material available at 10.1617/s11527-024-02337-7.
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Affiliation(s)
- Ueli M. Angst
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland
| | - Emanuele Rossi
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland
| | - Carolina Boschmann Käthler
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland
- Hagerbach Test Gallery Ltd., VSH, Flums, Switzerland
| | - David Mannes
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institut, Villigen, Switzerland
| | - Pavel Trtik
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institut, Villigen, Switzerland
| | - Bernhard Elsener
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland
| | - Zhou Zhou
- Department NPM2/RST, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Markus Strobl
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institut, Villigen, Switzerland
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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2
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Biggio D, Elsener B, Usai G, Fantauzzi M, Rossi A. Surface Chemistry of Passive Films on Ni-Free Stainless Steel: The Effect of Organic Components in Artificial Saliva. Langmuir 2024; 40:6824-6833. [PMID: 38498002 DOI: 10.1021/acs.langmuir.3c03728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
The composition and thickness of the passive film formed on the surface of an austenitic Ni-free DIN 1.4456 stainless steel (18% Cr, 18% Mn, and 2% Mo) used in orthodontics were investigated by X-ray photoelectron spectroscopy following contact with three complex artificial saliva solutions containing different organic components. It was found that the synergistic action of low pH and the presence of sodium citrate and lactic acid in the Darvell formulation resulted in thin passive films strongly enriched in chromium phosphates and oxyhydroxides and depleted in iron oxide. The differences in the surface chemistry of the passive film formed upon contact with the different artificial saliva formulations can be related to the more intense alloy dissolution in the active/passive transition, as shown by the polarization curves. Citrates or lactic acid can complex iron and promote alloy dissolution. The corrosion rates diminish with time, and after 16 h, they are found to be about 0.5 μm/year for all saliva formulations examined.
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Affiliation(s)
- Deborah Biggio
- Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari, Italy
| | - Bernhard Elsener
- Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari, Italy
| | - Giulia Usai
- Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari, Italy
| | - Marzia Fantauzzi
- Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari, Italy
| | - Antonella Rossi
- Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari, Italy
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3
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Biggio D, Fantauzzi M, Elsener B, Atzei D, Rossi A. The role of organic compounds in artificial saliva for corrosion studies: evidence from XPS analyses. SURF INTERFACE ANAL 2022. [DOI: 10.1002/sia.7149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Deborah Biggio
- Dipartimento di Scienze Chimiche e Geologiche Università di Cagliari Cagliari Italy
| | - Marzia Fantauzzi
- Dipartimento di Scienze Chimiche e Geologiche Università di Cagliari Cagliari Italy
| | - Bernhard Elsener
- Dipartimento di Scienze Chimiche e Geologiche Università di Cagliari Cagliari Italy
| | - Davide Atzei
- Dipartimento di Scienze Chimiche e Geologiche Università di Cagliari Cagliari Italy
| | - Antonella Rossi
- Dipartimento di Scienze Chimiche e Geologiche Università di Cagliari Cagliari Italy
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4
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Fiorito E, Porcedda GE, Brundu L, Passiu C, Atzei D, Ennas G, Elsener B, Fantauzzi M, Rossi A. Calcium carbonate as sorbent for lead removal from wastewaters. Chemosphere 2022; 296:133897. [PMID: 35218777 DOI: 10.1016/j.chemosphere.2022.133897] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/17/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Low-cost and largely available industrial by-products such as calcite (CaCO3) have been considered as sorbents to remediate wastewaters from toxic elements, such as lead, in compliance with the European circular economy strategy. To date few articles are reporting results on lead sorption at the calcite-water solution interface by X-ray photoelectron spectroscopy (XPS) and this investigation aims to clarifying the mechanism of the interaction of Pb2+ model solutions over a wide concentration range, from 0.1 μM to 80 mM, with commercial calcite. X-ray powder diffraction (XRPD), scanning electron microscopy (SEM, EDX) and XPS analysis indicate that when CaCO3 particles are soaked in Pb2+ 0.1 mM and 1 mM solutions, hexagonal platelets of hydrocerussite [(PbCO3)2 Pb(OH)2] precipitate on its surface. When the concentration of Pb2+ is equal or higher than 40 mM, prismatic acicula of cerussite [PbCO3] precipitate. Solution analysis by atomic emission spectroscopy (ICP-AES) and ICP-mass spectrometry (ICP-MS) indicate that Pb2+ removal efficiency is nearly 100%; when the initial Pb2+ concentration was equal to 0.1 μM it was below the limit of detection (LOD) and the efficiency could not be determined. The sorption capacity (qe) increases linearly with increasing initial Pb2+ concentration up to a value of 1680 (20) mg/g when the initial Pb2+concentration is 80 mM. These findings suggest that heterogeneous nucleation and surface co-precipitation occur and calcite can be well considered a very promising sorbent for Pb2+ removal from wastewaters within a wide initial concentration range.
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Affiliation(s)
- Elio Fiorito
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy
| | - Giovanni E Porcedda
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy
| | - Laura Brundu
- Laboratorio Chimico Nuorese, Via Mughina 121, 08100, Nuoro, Italy
| | - Cristiana Passiu
- Department of Materials, ETH Zürich, CH-8093, Zürich, Switzerland
| | - Davide Atzei
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy
| | - Guido Ennas
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy
| | - Bernhard Elsener
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy
| | - Marzia Fantauzzi
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy.
| | - Antonella Rossi
- Department of Chemical and Geological Sciences, Università di Cagliari, Campus of Monserrato (CA), I09042, Monserrato, Italy.
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Fantauzzi M, Elsener B, Cocco F, Passiu C, Rossi A. Model Protective Films on Cu-Zn Alloys Simulating the Inner Surfaces of Historical Brass Wind Instruments by EIS and XPS. Front Chem 2020; 8:272. [PMID: 32351939 PMCID: PMC7174669 DOI: 10.3389/fchem.2020.00272] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/20/2020] [Indexed: 11/13/2022] Open
Abstract
The present work focuses on the characterization of brass surfaces after contact with artificial saliva solution at pH 7.4 and phosphate buffer solution at pH 7 simulating two extreme conditions that might occur when playing ancient brass wind instruments in the context of historically informed performance practice. The composition and the morphology of the film formed following the contact with the solutions for 1, 3, and 16 h were investigated by ex situ X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) to shed a light on the surface changes upon time. In situ electrochemical impedance spectroscopy (EIS) was used to study the mechanism of corrosion and protection of the alloys. The results could be interpreted using a reliable equivalent electrical circuit; they provided evidence that the alloys behave differently when in contact to the various solutions. In saliva solution the formation on the brass surface of a thick surface film was observed, composed of crystallites of about 200 nm size mainly composed of CuSCN and Zn3(PO4)2. This layer hinders the alloy dissolution. The contact of the alloys with the buffer solution originated a much thinner layer composed of Cu2O, ZnO, and a small amount of Zn3(PO4)2. This film is rapidly formed and does not evolve upon time in a protective film.
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Affiliation(s)
- Marzia Fantauzzi
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cagliari, Italy.,INSTM, University of Cagliari Research Unit (UdR), Cagliari, Italy
| | - Bernhard Elsener
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cagliari, Italy.,INSTM, University of Cagliari Research Unit (UdR), Cagliari, Italy.,Institute for Building Materials, ETH Zurich, ETH Hönggerberg, Zurich, Switzerland
| | - Federica Cocco
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cagliari, Italy.,INSTM, University of Cagliari Research Unit (UdR), Cagliari, Italy
| | - Cristiana Passiu
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Antonella Rossi
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cagliari, Italy.,INSTM, University of Cagliari Research Unit (UdR), Cagliari, Italy
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6
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Stefanoni M, Angst UM, Elsener B. Kinetics of electrochemical dissolution of metals in porous media. Nat Mater 2019; 18:942-947. [PMID: 31358940 DOI: 10.1038/s41563-019-0439-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
Metals embedded in porous media interact electrochemically with the liquid phase contained in the pores. A widespread form of this, adversely affecting the integrity of engineered structures, is corrosion of steel in porous media or in natural environments. While it is well documented that the rate of this electrochemical dissolution process can vary over several orders of magnitude, understanding the underlying mechanisms remains a critical challenge hampering the development of reliable predictive models. Here we study the electrochemical dissolution kinetics of steel in meso-to-macro-porous media, using cement-based materials, wood and artificial soil as model systems. Our results reveal the dual role of the pore structure (that is, the influence on the electrochemical behaviour through transport limitations and an area effect, which is ultimately due to microscopic inhomogeneity of the metal/porous material interface). We rationalize the observations with the theory of capillary condensation and propose a material-independent model to predict the corrosion rate.
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Affiliation(s)
- Matteo Stefanoni
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland
| | - Ueli M Angst
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland.
| | - Bernhard Elsener
- Institute for Building Materials, ETH Zurich, Zurich, Switzerland
- Department of Chemical and Geological Science, University of Cagliari, Monserrato, Italy
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7
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Tang L, Frederiksen JM, Angst UM, Polder R, Alonso MC, Elsener B, Hooton D, Pacheco J. Experiences from RILEM TC 235-CTC in recommending a test method for chloride threshold values in concrete. RILEM Tech Lett 2018. [DOI: 10.21809/rilemtechlett.2018.55] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Chloride threshold value is an important input parameter in service life predictions. There has been a need for a reliable method for testing this value in order to improve the understanding of basic factors influencing the corrosion initiation. For this reason RILEM technical committee (TC) 235-CTC was formed with the ultimate aim to recommend a suitable test method capable of delivering data with acceptable measurement uncertainty. During the TC’s life, a test method was proposed and a Round-Robin Test (RRT) was organised to evaluate it. Due to the unexpected results from the RRT, the ultimate aim of the TC was not reached. There were some experiences obtained from the TC’s work especially in designing the test method which are worthy for supporting future researchers continuing to search for a reliable test method for it. This technical letter presents the TC’s experiences.
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8
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Stefanoni M, Zhang Z, Angst U, Elsener B. The kinetic competition between transport and oxidation of ferrous ions governs precipitation of corrosion products in carbonated concrete. RILEM Tech Lett 2018. [DOI: 10.21809/rilemtechlett.2018.57] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Corrosion products, originating from steel corrosion and precipitating in the concrete pore system, can lead to concrete cracking and to spalling of the concrete cover. Related premature structural repair causes high costs. Thus, reliable quantitative models are needed, which currently do not exist. Here, we present a new conceptual model to describe the fate of ferrous ions that are released at the steel surface during the corrosion process. The key novelty of our approach can be found in explicitly considering the kinetics of oxidation and transport of Fe2+ in the pore solution. These two processes constantly dilute the Fe2+ concentration and are in competition with the supply of Fe2+ from the anodic iron dissolution reaction. We use a numerical model to elucidate which of the described processes is the fastest. The results find good agreement with experimental data and reveal that under natural corrosion conditions, Fe2+ hardly reach the saturation level, which permits the diffusion of corrosion products up to millimeters away from the steel without necessarily leading to expansive stresses. Under accelerated corrosion conditions, however, precipitation is forced immediately at the steel surface. This fundamentally changes the cracking mechanism and questions the relevance of such tests and related models.
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Femenias YS, Angst U, Moro F, Elsener B. Development of a Novel Methodology to Assess the Corrosion Threshold in Concrete Based on Simultaneous Monitoring of pH and Free Chloride Concentration. Sensors (Basel) 2018; 18:s18093101. [PMID: 30223507 PMCID: PMC6164804 DOI: 10.3390/s18093101] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/08/2018] [Accepted: 09/11/2018] [Indexed: 11/23/2022]
Abstract
Both the free chloride concentration and the pH of the concrete pore solution are highly relevant parameters that control corrosion of the reinforcing steel. In this paper, we present a method to continuously monitor these two parameters in-situ. The approach is based on a recently developed electrode system that consists of several different potentiometric sensors as well as a data interpretation procedure. Instrumented mortar specimens containing different amounts of admixed chlorides were exposed to accelerated carbonation, and changes in free chloride concentration and pH were monitored simultaneously over time. The results revealed the stepwise decrease in pH as well as corresponding increases in free chlorides, resulting from the release of bound chlorides. For a pH drop of about 1 unit (from pH 13.5 down to pH 12.5), the free chloride concentration increased up to 1.5-fold. We continuously quantified the ratio Cl−/OH− that increased steeply with time, and was found to exceed a critical corrosion threshold long before carbonation can be detected with traditional indicator spray testing, even at admixed chloride contents in the order of allowable limits. These results can strongly influence the decision-making in engineering practice and it is expected to significantly improve condition assessments of reinforced concrete structures.
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Affiliation(s)
- Yurena Seguí Femenias
- Institute for Building Materials (IfB), ETH Zürich, Stefano-Franscini-Platz 3, 8093 Zurich, Switzerland.
| | - Ueli Angst
- Institute for Building Materials (IfB), ETH Zürich, Stefano-Franscini-Platz 3, 8093 Zurich, Switzerland.
| | - Fabrizio Moro
- Lafargeholcim Research Center, 95, rue du Montmurier, BP 15, 38291 Saint-Quentin Fallavier, France.
| | - Bernhard Elsener
- Institute for Building Materials (IfB), ETH Zürich, Stefano-Franscini-Platz 3, 8093 Zurich, Switzerland.
- Department of Chemical and Geological Sciences, University of Cagliari, 09100 Monserrato (CA), Italy.
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Stefanoni M, Angst UM, Elsener B. Electrochemistry and capillary condensation theory reveal the mechanism of corrosion in dense porous media. Sci Rep 2018; 8:7407. [PMID: 29743576 PMCID: PMC5943290 DOI: 10.1038/s41598-018-25794-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 04/24/2018] [Indexed: 11/09/2022] Open
Abstract
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.
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Affiliation(s)
- Matteo Stefanoni
- Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, Zurich, CH-8093, Switzerland
| | - Ueli M Angst
- Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, Zurich, CH-8093, Switzerland.
| | - Bernhard Elsener
- Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, Zurich, CH-8093, Switzerland.,University of Cagliari, Department of Chemical and Geological Science, I-09100, Monserrato, CA, Italy
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11
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Abstract
The pH of the concrete pore solution plays a vital role in protecting the reinforcing steel from corrosion. Here, we present results from embeddable pH sensors that permit the continuous, in-situ monitoring of the pH in the concrete pore solution. These are potentiometric sensors, based on thermally-oxidized iridium/iridium oxide (IrOx) electrodes. We propose an iterative calculation algorithm taking into account diffusion potentials arising from pH changes, thus permitting the reliable, non-destructive determination of the pore solution pH over time. This calculation algorithm forms an essential part of the method using IrOx electrodes. Mortar samples were exposed to accelerated carbonation and the pH was monitored at different depths over time. Comparative tests were also performed using thymolphthalein pH-indicator. The results from the pH sensors give insight in the carbonation process, and can, in contrast to thermodynamic modelling and titration experiments, give insight in kinetic processes such as transport and phases transformations. Additionally, it was found that the front at which the pH is decreased from initially 13-14 down to 12.5 can be significantly ahead of the common carbonation front corresponding to pH 9-10. This has major implications for laboratory testing and engineering practice.
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Scorciapino M, Fantauzzi M, Crobu M, Navarra G, Elsener B, Rossi A. Nanostructure of Surface Films on Ni18P Alloy in Sulfate Solutions by the Maximum Entropy Method. ACS Omega 2017; 2:7790-7802. [PMID: 31457337 PMCID: PMC6645160 DOI: 10.1021/acsomega.7b00958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 10/31/2017] [Indexed: 06/09/2023]
Abstract
NiP alloys are very often used in industry, due to their outstanding performance in corrosion and wear. Alloys with high phosphorus content (≥16 atom % P) are amorphous and show high corrosion resistance in both neutral and acidic solutions irrespective of the presence of chloride ions. The reason for this behavior is attributed to the formation of a "P-enriched surface layer" whose exact nature is still under debate. In this work, an iterative algorithm based on the application of maximum entropy method on nondestructive angle-resolved X-ray photoelectron spectroscopy data has been applied to the investigation of the surface layer grown on Ni18P alloys following mechanical polishing and anodic polarization in sulfate solutions. The results show that the outermost region of the examined alloy has a complex layered structure: (1) an uppermost hydrocarbon contamination layer about 1 nm thick, which includes also adsorbed water; (2) a nickel (poly)phosphate layer of about 1 nm; (3) a highly phosphorus-enriched interface being about 2 nm thick with a marked phosphorus concentration gradient, from 70 to 20 atom %; and (4) bulk alloy with the stoichiometric composition. These findings, together with the chemical state of the different phosphorus compounds, allow us to conclude that the high corrosion and wear resistance of NiP alloys might be ascribed to the presence of a thin, self-repairing nickel (poly)phosphate layer grown on a strongly P-enriched interface. Because the Auger parameter of P at the interface is similar to that of elemental P, it might be also concluded that the interface is enriched in elemental phosphorus.
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Angst UM, Boschmann C, Wagner M, Elsener B. Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures. J Vis Exp 2017. [PMID: 28892023 PMCID: PMC5614398 DOI: 10.3791/56229] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these structures. Corrosion of the embedded reinforcing steel is the most frequent cause for degradation. While it is well known that the ability of a structure to withstand corrosion depends strongly on factors such as the materials used or the age, it is common practice to rely on threshold values stipulated in standards or textbooks. These threshold values for corrosion initiation (Ccrit) are independent of the actual properties of a certain structure, which clearly limits the accuracy of condition assessments and service life predictions. The practice of using tabulated values can be traced to the lack of reliable methods to determine Ccrit on-site and in the laboratory. Here, an experimental protocol to determine Ccrit for individual engineering structures or structural members is presented. A number of reinforced concrete samples are taken from structures and laboratory corrosion testing is performed. The main advantage of this method is that it ensures real conditions concerning parameters that are well known to greatly influence Ccrit, such as the steel-concrete interface, which cannot be representatively mimicked in laboratory-produced samples. At the same time, the accelerated corrosion test in the laboratory permits the reliable determination of Ccrit prior to corrosion initiation on the tested structure; this is a major advantage over all common condition assessment methods that only permit estimating the conditions for corrosion after initiation, i.e., when the structure is already damaged. The protocol yields the statistical distribution of Ccrit for the tested structure. This serves as a basis for probabilistic prediction models for the remaining time to corrosion, which is needed for maintenance planning. This method can potentially be used in material testing of civil infrastructures, similar to established methods used for mechanical testing.
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Affiliation(s)
| | | | | | - Bernhard Elsener
- Institute for Building Materials, ETH Zurich; Department of Chemical and Geological Science, University of Cagliari
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14
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Angst UM, Elsener B. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures. Sci Adv 2017; 3:e1700751. [PMID: 28782038 PMCID: PMC5540240 DOI: 10.1126/sciadv.1700751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 06/28/2017] [Indexed: 06/07/2023]
Abstract
Forecasting the life of concrete infrastructures in corrosive environments presents a long-standing and socially relevant challenge in science and engineering. Chloride-induced corrosion of reinforcing steel in concrete is the main cause for premature degradation of concrete infrastructures worldwide. Since the middle of the past century, this challenge has been tackled by using a conceptual approach relying on a threshold chloride concentration for corrosion initiation (Ccrit). All state-of-the-art models for forecasting chloride-induced steel corrosion in concrete are based on this concept. We present an experiment that shows that Ccrit depends strongly on the exposed steel surface area. The smaller the tested specimen is, the higher and the more variable Ccrit becomes. This size effect in the ability of reinforced concrete to withstand corrosion can be explained by the local conditions at the steel-concrete interface, which exhibit pronounced spatial variability. The size effect has major implications for the future use of the common concept of Ccrit. It questions the applicability of laboratory results to engineering structures and the reproducibility of typically small-scale laboratory testing. Finally, we show that the weakest link theory is suitable to transform Ccrit from small to large dimensions, which lays the basis for taking the size effect into account in the science and engineering of forecasting the durability of infrastructures.
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Affiliation(s)
- Ueli M. Angst
- Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, Zurich CH-8093, Switzerland
| | - Bernhard Elsener
- Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, Zurich CH-8093, Switzerland
- Department of Chemical and Geological Science, University of Cagliari, I-09100 Monserrato, Cagliari, Italy
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Aronne A, Fantauzzi M, Imparato C, Atzei D, De Stefano L, D'Errico G, Sannino F, Rea I, Pirozzi D, Elsener B, Pernice P, Rossi A. Electronic properties of TiO2-based materials characterized by high Ti3+ self-doping and low recombination rate of electron–hole pairs. RSC Adv 2017. [DOI: 10.1039/c6ra27111a] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ti3+ self-doped black titania is obtained by a simple annealing in air without harsh conditions nor external reducing agents.
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Cocco F, Fantauzzi M, Elsener B, Rossi A. Dissolution of brass alloys naturally aged in neutral solutions – an electrochemical and surface analytical study. RSC Adv 2016. [DOI: 10.1039/c6ra18200c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Combining electrochemical and surface analytical information promotes the understanding of the dissolution mechanism of complex systems such as brass alloys.
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Affiliation(s)
- Federica Cocco
- Dipartimento di Scienze Chimiche e Geologiche
- Università Degli Studi di Cagliari
- UdR Cagliari
- Italy
| | - Marzia Fantauzzi
- Dipartimento di Scienze Chimiche e Geologiche
- Università Degli Studi di Cagliari
- UdR Cagliari
- Italy
| | - Bernhard Elsener
- Dipartimento di Scienze Chimiche e Geologiche
- Università Degli Studi di Cagliari
- UdR Cagliari
- Italy
- ETH Zurich
| | - Antonella Rossi
- Dipartimento di Scienze Chimiche e Geologiche
- Università Degli Studi di Cagliari
- UdR Cagliari
- Italy
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Elsener B, Alter M, Lombardo T, Ledergerber M, Wörle M, Cocco F, Fantauzzi M, Palomba S, Rossi A. A non-destructive in-situ approach to monitor corrosion inside historical brass wind instruments. Microchem J 2016. [DOI: 10.1016/j.microc.2015.10.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Abstract
Chemical state identification and quantification based on photoelectron spectra is challenging in the case of copper and zinc and their alloys.
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Affiliation(s)
- Federica Cocco
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- INSTM, UdR
- Cagliari
- Italy
| | - Bernhard Elsener
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- INSTM, UdR
- Cagliari
- Italy
| | - Marzia Fantauzzi
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- INSTM, UdR
- Cagliari
- Italy
| | - Davide Atzei
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- INSTM, UdR
- Cagliari
- Italy
| | - Antonella Rossi
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- INSTM, UdR
- Cagliari
- Italy
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Abstract
The identification of surface sulfide and polysulfide species based on the curve fitting of S2p photoelectron spectra and, for the first time, of X-ray excited S KLL Auger spectra has been performed.
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Affiliation(s)
- Marzia Fantauzzi
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Italy
- INSTM
- UdR
| | - Bernhard Elsener
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Italy
- INSTM
- UdR
| | - Davide Atzei
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Italy
- INSTM
- UdR
| | - Americo Rigoldi
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Italy
- INSTM
- UdR
| | - Antonella Rossi
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- Italy
- INSTM
- UdR
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Elsener B, Addari D, Coray S, Rossi A. Nickel-free manganese bearing stainless steel in alkaline media—Electrochemistry and surface chemistry. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.02.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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21
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Addari D, Elsener B, Rossi A. Electrochemistry and surface chemistry of stainless steels in alkaline media simulating concrete pore solutions. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.06.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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23
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24
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Elsener B, Atzei D, Krolikowski A, Rossi A. Effect of phosphorus concentration on the electronic structure of nanocrystalline electrodeposited Ni–P alloys: an XPS and XAES investigation. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2802] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Fantauzzi M, Elsener B, Atzei D, Lattanzi P, Rossi A. The surface of enargite after exposure to acidic ferric solutions: an XPS/XAES study. SURF INTERFACE ANAL 2007. [DOI: 10.1002/sia.2607] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fantauzzi M, Atzei D, Elsener B, Lattanzi P, Rossi A. XPS and XAES analysis of copper, arsenic and sulfur chemical state in enargites. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2348] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Olla M, Navarra G, Elsener B, Rossi A. Nondestructive in-depth composition profile of oxy-hydroxide nanolayers on iron surfaces from ARXPS measurement. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2362] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Contu F, Elsener B, Böhni H. Characterization of implant materials in fetal bovine serum and sodium sulfate by electrochemical impedance spectroscopy. II. Coarsely sandblasted samples. J Biomed Mater Res A 2003; 67:246-54. [PMID: 14517883 DOI: 10.1002/jbm.a.10113] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electrochemical impedance spectroscopy is used to investigate the corrosion resistance of coarsely sandblasted implant alloys, commercially pure titanium, Ti6Al4V, Ti6Al7Nb, and CoCrMo in 0.1M sodium sulfate and fetal bovine serum. Coarsely sandblasted samples have a heterogeneous surface constituted by a large number of protrusions and recessions. Impedance spectra collected in sodium sulfate present two time constants (maxima in the phase-angle of the bode plot) associated with the total surface and with the tips, respectively. In bovine serum, the two maxima in the impedance spectra cannot be distinguished because of the formation of an adsorption layer of organic molecules, which causes a decrease in the values of both the total and tips' capacitances as well as an increase in the polarization resistance. Ti6Al4V and Ti6Al7Nb show the highest corrosion rate both in serum and in sodium sulfate. Based on the capacitance values obtained in sodium sulfate, the real surface area of the coarsely sandblasted electrodes has been estimated relative to mechanically polished surfaces. The values of the effective electrode area correlate with the mechanical properties of the samples: in fact, the softest electrode (commercially pure titanium) shows the largest effective electrode area, whereas the hardest material (CoCrMo alloy) shows the smallest surface area.
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Affiliation(s)
- F Contu
- Center for Electrochemical Science and Engineering, POB 400745, 116 Engineer's Way, Charlottesville, Virginia 22904-4745, USA.
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Manfredini M, Marchetti A, Atzei D, Elsener B, Malagoli M, Galavotti F, Rossi A. Radiation-induced migration of additives in PVC-based biomedical disposable devices. Part 1. Surface morphology by AFM and SEM/XEDS. SURF INTERFACE ANAL 2003. [DOI: 10.1002/sia.1547] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Atzei D, Elsener B, Manfredini M, Marchetti A, Malagoli M, Galavotti F, Rossi A. Radiation-induced migration of additives in PVC-based biomedical disposable devices Part 2. Surface analysis by XPS. SURF INTERFACE ANAL 2003. [DOI: 10.1002/sia.1590] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Atzei D, Da Pelo S, Elsener B, Fantauzzi M, Frau F, Pierfranco L, Rossi A. The chemical state of arsenic in minerals of environmental interest--an XPS and an XAES study. Ann Chim 2003; 93:11-9. [PMID: 12650569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
A systematic analytical study using X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy (XAES) has been carried out to characterize the chemical state of arsenic in complex environmental samples. The conventional approach, which relies on the chemical shift of the core levels As3d, provides ambiguous results in determining the chemical environment of arsenic. A more accurate approach, based on the Auger parameter and on the Wagner (Chemical State) plot, which combines AsLMM kinetic energy and As3d binding energy, was adopted. This novel method for determining the chemical state of arsenic was employed to completely characterize arsenic in complex environmental samples.
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Affiliation(s)
- Davide Atzei
- Dipartimento di Chimica Inorganica ed Analitica, Cittadella Universitaria di Monserrato, Università degli Studi di Cagliari, 09100 Cagliari, Italy
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Manfredini M, Atzei D, Elsener B, Marchetti A, Rossi A. Degradation of plasticized PVC for biomedical disposable device under soft x-ray irradiation. SURF INTERFACE ANAL 2003. [DOI: 10.1002/sia.1532] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Contu F, Elsener B, Böhni H. Characterization of implant materials in fetal bovine serum and sodium sulfate by electrochemical impedance spectroscopy. I. Mechanically polished samples. J Biomed Mater Res 2002; 62:412-21. [PMID: 12209927 DOI: 10.1002/jbm.10329] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electrochemical impedance spectroscopy is used to monitor the long-term stability (up to 150 days) of mechanically polished commercial pure titanium, Ti6Al4V, Ti6Al7Nb, and CoCrMo alloys in 0.1M sodium sulfate and fetal bovine serum. A capacitive spectrum in the frequency range from 10(-3) to 10(5) Hz is always found and the impedance spectra can be fitted by a simple parallel RC circuit with a constant phase element. The open circuit potential observed in serum is always more cathodic and the polarization resistance (R(p)) is higher than that recorded in sodium sulfate solutions. The observed variation of the equivalent capacitance in serum bovine suggests that an adsorption layer of organic molecules develops on the electrode surface and it is responsible for both the decrease in open circuit potential and the higher R(p), because it hinders the oxygen evolution reaction and the charge transfer responsible for the passive film dissolution (or growth). Among the alloys studied, Ti6Al4V displayed the highest steady-state values of R(p) both in serum and in sodium sulfate.
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Affiliation(s)
- F Contu
- Institute of Materials Chemistry and Corrosion, Swiss Federal Institute of Technology Zurich 8093 Zurich, Switzerland.
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Mantovani G, Macciò A, Madeddu C, Mura L, Gramignano G, Lusso MR, Mulas C, Mudu MC, Murgia V, Camboni P, Massa E, Ferreli L, Contu P, Rinaldi A, Sanjust E, Atzei D, Elsener B. Quantitative evaluation of oxidative stress, chronic inflammatory indices and leptin in cancer patients: correlation with stage and performance status. Int J Cancer 2002; 98:84-91. [PMID: 11857390 DOI: 10.1002/ijc.10143] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In advanced cancer patients, the oxidative stress could take place either at the onset of disease or as a function of disease progression. To test this hypothesis, the following parameters were investigated: the erythrocyte activity of the enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), the serum activity of glutathione reductase (GR) and the serum total antioxidant status (TAS). The total antioxidant capacity of plasma LMWA was evaluated by the cyclic voltammetry methodology. We further determined the serum levels of proinflammatory cytokines (IL-6 and TNFalpha), IL-2, leptin and C-reactive protein (CRP). All of these parameters have been correlated with the most important clinical indices of patients such as Stage of disease, ECOG PS and clinical response. Eighty-two advanced stage cancer patients and 36 healthy individuals used as controls were included in the study. Our findings show that SOD activity was significantly higher in cancer patients than in controls and GPx activity was significantly lower in cancer patients than in controls. Serum values of IL-6, TNFalpha and CRP were significantly higher in patients than in controls. Serum leptin values of cancer patients were significantly lower than controls. SOD activity increased significantly from Stage II/ECOG 0-1 to Stage IV/ECOG 0-1, whereas it decreased significantly in Stage IV/ECOG 3. GPx activity decreased significantly in Stage IV/ECOG 2-3. An inverse correlation between ECOG PS and serum leptin levels was found. Serum levels of IL-2 decreased from Stage II/ECOG 0-1 to Stage IV/ECOG 2-3. A direct correlation between Stage/ECOG PS and serum levels of both IL-6 and CRP was observed. Cisplatin administration induced a significant increase of GPx after 24 hr. In conclusion, this is the first study that shows that several "biological" parameters of cancer patients such as antioxidant enzyme activity, cytokines, leptin and CRP strictly correlate with the most important clinical parameters of disease such as Stage and ECOG PS.
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Affiliation(s)
- Giovanni Mantovani
- Department of Medical Oncology, University of Cagliari, Cagliari, Italy.
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Rossi A, Elsener B, H�hner G, Textor M, Spencer ND. XPS, AES and ToF-SIMS investigation of surface films and the role of inclusions on pitting corrosion in austenitic stainless steels. SURF INTERFACE ANAL 2000. [DOI: 10.1002/1096-9918(200007)29:7<460::aid-sia889>3.0.co;2-t] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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