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Leygraf, ChristopherORCID iD iconorcid.org/0000-0002-9453-1333
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Publications (10 of 204) Show all publications
Chang, T., Odnevall Wallinder, I., de la Fuente, D., Chico, B., Morcillo, M., Welter, J.-M. -. & Leygraf, C. (2017). Analysis of historic copper patinas. Influence of inclusions on patina uniformity. Materials, 10(3), Article ID 298.
Open this publication in new window or tab >>Analysis of historic copper patinas. Influence of inclusions on patina uniformity
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2017 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 10, no 3, article id 298Article in journal (Refereed) Published
Abstract [en]

The morphology and elemental composition of cross sections of eight historic copper materials have been explored. The materials were taken from copper roofs installed in different middle and northern European environments from the 16th to the 19th century. All copper substrates contain inclusions of varying size, number and composition, reflecting different copper ores and production methods. The largest inclusions have a size of up to 40 μm, with most inclusions in the size ranging between 2 and 10 μm. The most common element in the inclusions is O, followed by Pb, Sb and As. Minor elements include Ni, Sn and Fe. All historic patinas exhibit quite fragmentized bilayer structures, with a thin inner layer of cuprite (Cu2O) and a thicker outer one consisting mainly of brochantite (Cu4SO4(OH)6). The extent of patina fragmentation seems to depend on the size of the inclusions, rather than on their number and elemental composition. The larger inclusions are electrochemically nobler than the surrounding copper matrix. This creates micro-galvanic effects resulting both in a profound influence on the homogeneity and morphology of historic copper patinas and in a significantly increased ratio of the thicknesses of the brochantite and cuprite layers. The results suggest that copper patinas formed during different centuries exhibit variations in uniformity and corrosion protection ability.

Place, publisher, year, edition, pages
MDPI AG, 2017
Keyword
Antlerite, Atmospheric corrosion, Bilayer, Brochantite, Cuprite, Historic copper, Inclusions, Micro-galvanic effect, Patina, Volta potential, Antimony, Copper corrosion, Corrosion, Lead, Metallic matrix composites, Ores, Substrates, Bi-layer, Galvanic effect, Copper
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-207437 (URN)10.3390/ma10030298 (DOI)000400863500081 ()2-s2.0-85015630454 (Scopus ID)
Note

QC 20170523

Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2017-11-29Bibliographically approved
Morcillo, M., Chang, T., Chico, B., de la Fuente, D., Odnevall Wallinder, I., Jimenez, J. A. & Leygraf, C. (2017). Characterisation of a centuries-old patinated copper roof tile from Queen Anne's Summer Palace in Prague. Materials Characterization, 133, 146-155.
Open this publication in new window or tab >>Characterisation of a centuries-old patinated copper roof tile from Queen Anne's Summer Palace in Prague
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2017 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 133, p. 146-155Article in journal (Refereed) Published
Abstract [en]

This paper presents an in-depth characterisation study of the patina formed on a copper tile taken from the roof of Queen Anne's Summer Palace in Prague after > 300 years of exposure to the action of the atmosphere. A wide variety of techniques have been used, including metallographic and chemical analysis (electrogravimetry, AAS, XRF) of the copper matrix, and spectroscopic and microscopic investigations (GIXRD, FTIR, TEM/EDS and SEM/ EDS) to determine the composition and structure of the patina. The major conclusions of the study are: (a) the base copper contains abundant inclusions mainly of rosiaite (PbSb2O6); (b) the patina is formed by an inner sublayer of cuprite (Cu2O) and an outer sublayer of brochantite [Cu4SO4(OH)(6)] and antlerite [Cu3SO4(OH)(4)] and traces of azurite [Cu-3(CO3)(2)(OH)(2)]; and (c) the brochantite/antlerite crystals are randomly doped with Fe and C.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE INC, 2017
Keyword
Copper tile, Atmospheric corrosion, Characterisation, Patina, Queen Anne's Summer Palace
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-217414 (URN)10.1016/j.matchar.2017.09.034 (DOI)000413881500018 ()2-s2.0-85030706571 (Scopus ID)
Note

QC 20171121

Available from: 2017-11-21 Created: 2017-11-21 Last updated: 2017-11-21Bibliographically approved
Halldin Stenlid, J., Johansson, A. J., Leygraf, C. & Brinck, T. (2017). Computational Analysis of the Early Stage of Cuprous Oxide Sulphidation: A Top-Down Process. Corrosion Engineering, Science and Technology, 52(S1), 50-53.
Open this publication in new window or tab >>Computational Analysis of the Early Stage of Cuprous Oxide Sulphidation: A Top-Down Process
2017 (English)In: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 52, no S1, p. 50-53Article in journal (Refereed) Published
Abstract [en]

The initial steps of Cu2O sulphidation to Cu2S have been studied using plane-wave density functional theory at the PBE-D3+U level of sophistication. Surface adsorption and dissociation of H2S and H2O, as well as the replacement reaction of lattice oxygen with sulphur, have been investigated for the most stable (111) and (100) surface facets under oxygen-lean conditions. We find that the (100) surface is more susceptible to sulphidation than the (111) surface, promoting both H2S adsorption, dissociation and the continued oxygen–sulphur replacement. The results presented in this proceeding bridge previous results from high-vacuum experiments on ideal surface to more realistic corrosion conditions and set the grounds for future mechanistic studies. Potential implications on the long-term final disposal of spent nuclear fuel are discussed.

Keyword
Density functional theory, sulphidation, cuprite (Cu2O), corrosion, water (H2O), hydrogen sulphide (H2S), nuclear waste disposal, chalcocite (Cu2S)
National Category
Chemical Sciences
Research subject
Materials Science and Engineering; Chemistry; Theoretical Chemistry and Biology
Identifiers
urn:nbn:se:kth:diva-212933 (URN)10.1080/1478422X.2017.1284393 (DOI)
Note

QC 20170829

Available from: 2017-08-24 Created: 2017-08-24 Last updated: 2017-08-29Bibliographically approved
Mameng, S. H., Pettersson, R. & Leygraf, C. (2017). Effect of Stainless Steel Composition on Atmospheric Corrosion Resistance at a Marine Site in Dubai. Corrosion, 73(7), 880-891.
Open this publication in new window or tab >>Effect of Stainless Steel Composition on Atmospheric Corrosion Resistance at a Marine Site in Dubai
2017 (English)In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 73, no 7, p. 880-891Article in journal (Refereed) Published
Abstract [en]

The influence of the composition of stainless steels on atmospheric corrosion resistance in a marine environment in Dubai was investigated after 2 y and 4 y of exposure. Different stainless steel grades with different surface finishes were included in the investigation: three ferritic stainless steels, five austenitic stainless steels, and four duplex stainless steels. The alloying elements chromium (Cr) and molybdenum (Mo) both had a beneficial influence on the corrosion resistance. The pitting resistance equivalent number (PREN =%Cr + 3.3%Mo + 16%N) and the (%Cr + 3.3%Mo) content in the surface film correlated well to the atmospheric corrosion resistance. An increased Cr content both in the bulk material and in the passive film improved the atmospheric corrosion resistance and the additional presence of Mo was effective in preventing red rust and also reduced the depth of pits. The depth of the pitting attack and the degree of aesthetic degradation were both influenced by alloying level, surface finish, and exposure conditions (open and sheltered). In the severe marine environment in Dubai, it is necessary to use Mo-bearing high-Cr stainless steel for adequate atmospheric corrosion resistance. The most resistant stainless steel grades were the high alloyed grades which ranked in the order UNS S31254 similar to UNS S3750 < UNS S34565 < UNS S32654. The duplex stainless steel grade S32205 may be considered for construction and architectural materials in Dubai but is likely to require more maintenance.

Place, publisher, year, edition, pages
NATL ASSOC CORROSION ENG, 2017
Keyword
alloying composition, appearance rating, atmospheric corrosion, marine environment, rust and stain, surface film
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-210340 (URN)10.5006/2372 (DOI)000403213200010 ()2-s2.0-85021262110 (Scopus ID)
Note

QC 20170704

Available from: 2017-07-04 Created: 2017-07-04 Last updated: 2017-07-04Bibliographically approved
Yin, L., Jin, Y., Leygraf, C., Birbilis, N. & Pan, J. (2017). Numerical Simulation of Micro-Galvanic Corrosion in Al Alloys: Effect of Geometric Factors. Journal of the Electrochemical Society, 164(2), C75-C84.
Open this publication in new window or tab >>Numerical Simulation of Micro-Galvanic Corrosion in Al Alloys: Effect of Geometric Factors
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2017 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 2, p. C75-C84Article in journal (Refereed) Published
Abstract [en]

A finite element model for simulating the propagation of intermetallic particle driven micro-galvanic corrosion in an Al-matrix model system is presented. The model revealed dynamic changes related to localized corrosion, including the moving dissolution boundary, the deposition of reaction products (Al(OH)(3)), and their blocking effect. Modelling was focused on the effects of key geometric parameters, including the radius of cathodic particle (range 0.5 to 4 mu m) and the width of an assumed anodic ring surrounding the particle (range 0.1 to 2 mu m). Simulations revealed the dynamic flow of molecular and ionic species, along with influence of geometrical constraints. For ring widths below 0.5 mu m, deposition of Al(OH)(3) inside the dissolving volume was inhibited due to limited transport of OH- and O-2 into a constrained volume - resulting in local acidification. An increase in cathodic particle radius at given ring width resulted in a greater dissolution by providing a larger cathodic area for O-2 reduction, quantifying the effect of cathode/anode ratio. The model was also developed to include two cathodic particles to explore any interaction. The present study reveals a physicochemical model that contributes toward a framework for multi-process localized corrosion systems, which can be further adapted to commercial alloy systems.

Place, publisher, year, edition, pages
ELECTROCHEMICAL SOC INC, 2017
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-206310 (URN)10.1149/2.1221702jes (DOI)000397850800024 ()
Note

QC 20170505

Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2017-05-05Bibliographically approved
Morcillo, M., Chico, B., de la Fuente, D., Aicantara, J., Odnevall Wallinder, I. & Leygraf, C. (2017). On the Mechanism of Rust Exfoliation in Marine Environments. Journal of the Electrochemical Society, 164(2), C8-C16.
Open this publication in new window or tab >>On the Mechanism of Rust Exfoliation in Marine Environments
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2017 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 2, p. C8-C16Article in journal (Refereed) Published
Abstract [en]

Based on exposures in chloride-rich field and laboratory atmospheres, a mechanism of rust exfoliation of carbon steel is proposed. Key ingredients are structural transformations between main rust phases (goethite, lepidocrocite, spinel oxides and akageneite) during varying exposure conditions and their large difference in molar volume with a factor of five between the most compact and least compact rust phase. Akaganeite transformed to spinel results in volume contraction, lepidocrocite to spinel in volume expansion and in both cases stresses are introduced in the rust multilayer. At sufficiently high chloride deposition rates (similar to 300 mg/m(2).d), the rust multilayer eventually detaches resulting in rust exfoliation.

Place, publisher, year, edition, pages
ELECTROCHEMICAL SOC INC, 2017
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-206309 (URN)10.1149/2.0131702jes (DOI)000397850800016 ()
Note

QC 20170505

Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2017-05-05Bibliographically approved
Yin, L., Jin, Y., Leygraf, C. & Pan, J. (2016). A FEM model for investigation of micro-galvanic corrosion of Al alloys and effects of deposition of corrosion products. Electrochimica Acta, 192, 310-318.
Open this publication in new window or tab >>A FEM model for investigation of micro-galvanic corrosion of Al alloys and effects of deposition of corrosion products
2016 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 192, p. 310-318Article in journal (Refereed) Published
Abstract [en]

A finite element method model has been elaborated aiming at a deeper insight into the influence of microstructure on micro-galvanic corrosion of Al alloys. The model considers a dynamic corroding surface and takes into account kinetic data from local electrochemical reactions, transport of O-2 and ionic species (e.g., Al3+, H+, Cl-), homogeneous reactions in the electrolyte, deposition of reaction products and its influence on both anodic and cathodic reactions. As a first step, an Al matrix with a micrometer-sized cathodic intermetallic particle exposed in 0.1 M NaCl has been considered. The simulation predicts the dynamic changes of the corroding surface, and the flow and distribution of ionic species and of O-2 in space and time. The calculated pH of the electrolyte inside and nearby the occluded corroding volume suggests the formation of insoluble Al(OH)(3) on both the cathodic and anodic areas. This results in blocking effects of anodic and cathodic reactions and in eventual termination of the micro-galvanic corrosion. The predicted deposition of corrosion product is in good agreement with in-situ atomic force microscopy measurements.

Place, publisher, year, edition, pages
Elsevier, 2016
Keyword
FEM model, Al alloy, micro-galvanic corrosion, deposition, blocking effect
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-184970 (URN)10.1016/j.electacta.2016.01.179 (DOI)000371143600036 ()2-s2.0-84957871682 (Scopus ID)
Note

QC 20160407

Available from: 2016-04-07 Created: 2016-04-07 Last updated: 2017-11-30Bibliographically approved
Hosseinpour, S., Forslund, M., Johnson, C. M., Pan, J. & Leygraf, C. (2016). Atmospheric corrosion of Cu, Zn, and Cu-Zn alloys protected by self-assembled monolayers of alkanethiols. Surface Science, 648, 170-176.
Open this publication in new window or tab >>Atmospheric corrosion of Cu, Zn, and Cu-Zn alloys protected by self-assembled monolayers of alkanethiols
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2016 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 648, p. 170-176Article in journal (Refereed) Published
Abstract [en]

In this article results from earlier studies have been compiled in order to compare the protection efficiency of self-assembled monolayers (SAM) of alkanethiols for copper, zinc, and copper-zinc alloys exposed to accelerated indoor atmospheric corrosion conditions. The results are based on a combination of surface spectroscopy and microscopy techniques. The protection efficiency of investigated SAMs increases with chain length which is attributed to transport hindrance of the corrosion stimulators in the atmospheric environment, water, oxygen and formic acid, towards the copper surface. The transport hindrance is selective and results in different corrosion products on bare and on protected copper. Initially the molecular structure of SAMs on copper is well ordered, but the ordering is reduced with exposure time. Octadecanethiol (ODT), the longest alkanethiol investigated, protects copper significantly better than zinc, which may be attributed to the higher bond strength of Cu-S than of Zn-S. Despite these differences, the corrosion protection efficiency of ODT for the single phase Cu20Zn brass alloy is equally efficient as for copper, but significantly less for the heterogeneous double phase Cu40Zn brass alloy.

Place, publisher, year, edition, pages
Elsevier, 2016
Keyword
Self-assembled monolayers, Copper, Brass, Atmospheric corrosion, Vibrational sum frequency spectroscopy, Infrared reflection/absorption spectroscopy
National Category
Condensed Matter Physics Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-186550 (URN)10.1016/j.susc.2015.10.045 (DOI)000374198600025 ()2-s2.0-84958770816 (Scopus ID)
Note

QC 20160513

Available from: 2016-05-13 Created: 2016-05-13 Last updated: 2017-11-30Bibliographically approved
Leygraf, C., Odnevall Wallinder, I., Tidblad, J. & Graedel, T. (2016). Atmospheric Corrosion: Second Edition. In: : (pp. 1-374). Wiley Blackwell.
Open this publication in new window or tab >>Atmospheric Corrosion: Second Edition
2016 (English)Chapter in book (Other academic)
Abstract [en]

Presents a comprehensive look at atmospheric corrosion, combining expertise in corrosion science and atmospheric chemistry Is an invaluable resource for corrosion scientists, corrosion engineers, and anyone interested in the theory and application of Atmospheric Corrosion Updates and expands topics covered to include, international exposure programs and the environmental effects of atmospheric corrosion Covers basic principles and theory of atmospheric corrosion chemistry as well as corrosion mechanisms in controlled and uncontrolled environments Details degradation of materials in architectural and structural applications, electronic devices, and cultural artifacts Includes appendices with data on specific materials, experimental techniques, atmospheric species.

Place, publisher, year, edition, pages
Wiley Blackwell, 2016
Series
Atmospheric Corrosion: Second Edition
National Category
Other Chemistry Topics Other Materials Engineering Composite Science and Engineering Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:kth:diva-197216 (URN)10.1002/9781118762134 (DOI)2-s2.0-84983268537 (Scopus ID)9781118762134 (ISBN); 9781118762271 (ISBN) (ISBN)
Note

QC 20161207

Available from: 2016-12-07 Created: 2016-11-30 Last updated: 2016-12-07Bibliographically approved
Mameng, S. H., Pettersson, R., Wegrelius, L. & Leygraf, C. (2016). Effect of surface finishes on the atmospheric corrosion of duplex grade UNS S32205; Results of a field exposure program in Dubai. In: Corrosion 2016: . Paper presented at 6 March 2016 through 10 March 2016 (pp. 959-973). National Assoc. of Corrosion Engineers International.
Open this publication in new window or tab >>Effect of surface finishes on the atmospheric corrosion of duplex grade UNS S32205; Results of a field exposure program in Dubai
2016 (English)In: Corrosion 2016, National Assoc. of Corrosion Engineers International , 2016, p. 959-973Conference paper, Published paper (Refereed)
Abstract [en]

The duplex grade UNS S32205 is an excellent choice in many marine environments where UNS S31603 is on the borderline in regards to atmospheric corrosion resistance. The properties of S32205 make it well suited for construction with respect to strength, reduced maintenance, durability and long-term service. In marine environments the use of a sufficiently highly alloyed stainless steel, often in combination with a good surface finish and adequate maintenance, is required to maintain pristine surfaces The main objective with this paper is to present information about the effect of different surface finishes on the corrosion and aesthetic appearance of the duplex grade S32205 exposed at a marine test site in Dubai, UAE. The results obtained include the effect of characteristics such as surface roughness, surface treatment and surface orientation after several years of exposure. Results show that duplex grade UNS S32205 can be considered for architectural materials in severe marine locations such as the Dubai site. A smooth surface and an appropriate surface treatment give improved corrosion resistance. Chromium and silicon in the passive film were found to be beneficial in terms of resistance to aesthetic degradation. A correlation was observed between aqueous corrosion resistance measured in laboratory pitting corrosion tests and the atmospheric field test results.

Place, publisher, year, edition, pages
National Assoc. of Corrosion Engineers International, 2016
Keyword
Appearance, Atmospheric corrosion, Duplex stainless steel UNS S32205, Pitting, Surface finish, Corrosion, Corrosion resistance, Finishing, Marine engineering, Stainless steel, Surface roughness, Architectural material, Atmospheric fields, Duplex stainless steel, Long term service, Marine environment, Surface finishes, Surface orientation, Surface treatment
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-195503 (URN)2-s2.0-84991312302 (Scopus ID)9781510821354 (ISBN)
Conference
6 March 2016 through 10 March 2016
Note

QC 20161125

Available from: 2016-11-25 Created: 2016-11-03 Last updated: 2016-11-25Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-9453-1333

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