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Leygraf, ChristopherORCID iD iconorcid.org/0000-0002-9453-1333
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Publications (10 of 217) Show all publications
Liu, M., Jin, Y., Leygraf, C. & Pan, J. (2019). A DFT-Study of Cl Ingress into alpha-Al2O3(0001) and Al(111) and Its Possible Influence on Localized Corrosion of Al. Journal of the Electrochemical Society, 166(11), C3124-C3130
Open this publication in new window or tab >>A DFT-Study of Cl Ingress into alpha-Al2O3(0001) and Al(111) and Its Possible Influence on Localized Corrosion of Al
2019 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, no 11, p. C3124-C3130Article in journal (Refereed) Published
Abstract [en]

Ingress of chloride into alpha-Al2O3(0001) and Al(111) was calculated by first-principles theory calculations by considering Cl insertion into Al or O vacancies within alpha-Al2O3(0001) or into vacancy or interstitial sites within Al(111). For alpha-Al2O3, the formation of an O vacancy is energetically more favorable than of an Al vacancy. The insertion of Cl into an O vacancy is also more favorable than into an Al vacancy. A high energy-barrier has been derived for Cl transport within the neighboring O vacancies. In addition, the work function decreases with Cl ingress into the interior of the oxide. For Al(111), Cl insertion into either an Al vacancy or an interstitial site is less favorable compared to the insertion into alpha-Al2O3. The work function only changes slightly with Cl insertion into an Al vacancy. Moreover, the pre-inserted Cl reduces the energy-barrier for further Cl ingress into alpha-Al2O3, whereas Cl tends to stay in the sub-surface layer of Al(111), suggesting Cl accumulation at the Al2O3/Al.

Place, publisher, year, edition, pages
ELECTROCHEMICAL SOC INC, 2019
Keywords
LLEY B, 1990, JOURNAL OF CHEMICAL PHYSICS, V92, P508
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:kth:diva-251275 (URN)10.1149/2.0161911jes (DOI)000465526200002 ()
Note

QC 20190515

Available from: 2019-05-15 Created: 2019-05-15 Last updated: 2019-05-15Bibliographically approved
Örnek, C., Leygraf, C. & Pan, J. (2019). Passive film characterisation of duplex stainless steel using scanning Kelvin probe force microscopy in combination with electrochemical measurements. npJ Materials Degradation, 3(1), 1-8
Open this publication in new window or tab >>Passive film characterisation of duplex stainless steel using scanning Kelvin probe force microscopy in combination with electrochemical measurements
2019 (English)In: npJ Materials Degradation, ISSN 2397-2106, Vol. 3, no 1, p. 1-8Article in journal (Refereed) Published
Abstract [en]

The characterisation of passive oxide films on heterogeneous microstructures is needed to assess local degradation (corrosion, cracking) in aggressive environments. The Volta potential is a surface-sensitive parameter which can be used to assess the surface nobility and hence passive films. In this work, it is shown that the Volta potential, measured on super duplex stainless steel by scanning Kelvin probe force microscopy, correlates with the electrochemical properties of the passive film, measured by electrochemical impedance spectroscopy and potentiodynamic polarisation. Natural oxidation by ageing in ambient air as well as artificial oxidation by immersion in concentrated nitric acid improved the nobility, both reflected by increased Volta potentials and electrochemical parameters. Passivation was associated with vanishing of the inherent Volta potential difference between the ferrite and austenite, thereby reducing the galvanic coupling and hence improving the corrosion resistance of the material. Hydrogen-passive film interactions, triggered by cathodic polarisation, however, largely increased the Volta potential difference between the phases, resulting in loss of electrochemical nobility, with the ferrite being more affected than the austenite. A correlative approach of using the Volta potential in conjunction with electrochemical data has been introduced to characterise the nobility of passive films in global and local scale.

Keywords
Scanning Kelvin probe force microscopy; SKPFM; Volta potential; Duplex Stainless Steel; Corrosion; Electrochemical Nobility; Electrochemical Measurements; Polarization; Electrochemical Impedance Spectroscopy
National Category
Metallurgy and Metallic Materials Materials Engineering Corrosion Engineering Condensed Matter Physics
Research subject
Materials Science and Engineering
Identifiers
urn:nbn:se:kth:diva-248530 (URN)10.1038/s41529-019-0071-8 (DOI)
Note

QC 20190507

Available from: 2019-04-09 Created: 2019-04-09 Last updated: 2019-05-07Bibliographically approved
Chang, T., Herting, G., Goidanich, S., Sánchez Amaya, J. M., Arenas, M. A., Le Bozec, N., . . . Odnevall Wallinder, I. (2019). The role of Sn on the long-term atmospheric corrosion of binary Cu-Sn bronze alloys in architecture. Corrosion Science, 149, 54-67
Open this publication in new window or tab >>The role of Sn on the long-term atmospheric corrosion of binary Cu-Sn bronze alloys in architecture
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2019 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 149, p. 54-67Article in journal (Refereed) Published
Abstract [en]

The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4–6 wt.% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Aesthetic appearance, Atmospheric corrosion, Bronze, Metal release, Patina
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-246467 (URN)10.1016/j.corsci.2019.01.002 (DOI)000459839700006 ()2-s2.0-85059532533 (Scopus ID)
Note

QC 20190328

Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-03-28Bibliographically approved
Chang, T., Herting, G., Goidanich, S., Sanchez Amaya, J. M., Arenas, M. A., Le Bozec, N., . . . Odnevall Wallinder, I. (2019). The role of Sn on the long-term atmospheric corrosion of binary Cu-Sn bronze alloys in architecture. Corrosion Science, 149, 54-67
Open this publication in new window or tab >>The role of Sn on the long-term atmospheric corrosion of binary Cu-Sn bronze alloys in architecture
Show others...
2019 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 149, p. 54-67Article in journal (Refereed) Published
Abstract [en]

The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4-6 wt.% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Bronze, Atmospheric corrosion, Patina, Metal release, Aesthetic appearance, SLOUIS C, 1993, ELECTROCHIMICA ACTA, V38, P2781 yer H.E., 1985, yer J.H., 1992, Bronze Corrosion: Rates and Chemical Processes, the Conservation of Bronze Sculpture in the Outdoor Environment: a Dialogue Among Conservators, Curators, Environmental Scientists, and Corrosion Engineers, P103 hweizer F., 1994, Bronze Objects From Lake Sites: From Patina to Biography, Ancient and Historic Metals: Conservation and Scientific Research, P33 nonymous], ISO 9226, armaraj N, 2006, SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, V64, P136 W., 2001, Water Air Soil Pollut. Focus, V1, P67 ott DA, 2000, STUDIES IN CONSERVATION, V45, P39 otkova D., 1996, Proc. of Art' 96
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-246227 (URN)10.1016/j.corsci.2019.01.002 (DOI)000459839700006 ()2-s2.0-85059532533 (Scopus ID)
Note

QC 20190404

Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2019-04-04Bibliographically approved
Chang, T., Leygraf, C., Odnevall Wallinder, I. & Jin, Y. (2019). Understanding the Barrier Layer Formed via Adding BTAH in Copper Film Electrodeposition. Journal of the Electrochemical Society, 166(2), D10-D20
Open this publication in new window or tab >>Understanding the Barrier Layer Formed via Adding BTAH in Copper Film Electrodeposition
2019 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, no 2, p. D10-D20Article in journal (Refereed) Published
Abstract [en]

The influence of surface adsorption of benzotriazole (BTAH) and of chloride ions (Cl-) on the kinetics of copper electrodeposition/dissolution in copper sulfate solutions and on copper deposit characteristics have been investigated using electrochemical quartz crystal microbalance (EQCM) combined with cyclic voltammetry (CV). The addition of BTAH alone increases the overpotential of copper deposition, whereas a Cu(I)BTA complex forms at potentials higher than 0.08 V (vs. SCE) accompanied with the occurrence of copper anodic dissolution. With simultaneous addition of BTAH and Cl-, surface adsorption of Cl- competes with that of BTAH during the initial stage of copper nucleation. Different cuprous reaction intermediates form in the examined potential range -0.4 to 0.3 V (vs. SCE), which partly eliminate the favorable effect of BTAH on the deposited copper. A BTAH-containing adsorbed layer formed on the matte side of electrodeposited copper film in the presence of BTAH with or without Cl-, exhibiting a barrier surface property and an improved corrosion resistance compared with the copper film electrodeposited in the electrolyte without addition of BTAH.

Place, publisher, year, edition, pages
ELECTROCHEMICAL SOC INC, 2019
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-241310 (URN)10.1149/2.0041902jes (DOI)000455193100001 ()
Note

QC 20190125

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-01-25Bibliographically approved
Zhang, X., Odnevall Wallinder, I. & Leygraf, C. (2018). Atmospheric corrosion of Zn-Al coatings in a simulated automotive environment. Surface Engineering, 34(9), 641-648
Open this publication in new window or tab >>Atmospheric corrosion of Zn-Al coatings in a simulated automotive environment
2018 (English)In: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 34, no 9, p. 641-648Article in journal (Refereed) Published
Abstract [en]

Accelerated NVDA (VDA 233-102) tests were performed on bare Zn and Al sheets, Galfan coating (Zn-5 wt-% Al) and Galvalume coating (Zn-55 wt-% Al) on steel. ZnO, Zn(OH)(2) and Zn-5(OH)(8)Cl-2 center dot H2O were the main corrosion products identified on both bare Zn sheet and Galfan. AlOOH and Al(OH)(3) were preferentially formed on bare Al sheet and Galvalume. In addition, Zn-Al-containing corrosion products, Zn6Al2(OH)(16)CO3 center dot 4H(2)O and/or Zn2Al(OH)(6)Cl center dot 2H(2)O were identified on both Galfan and Galvalume. Corrosion products of Zn6Al2(OH)(16)CO3 center dot 4H(2)O with a platelet morphology were preferentially formed in the zinc-rich interdendritic regions of the Galvalume surface. Galfan revealed a similar corrosion behaviour as bare Zn sheet, whereas Galvalume exhibited similar behaviour as bare Al sheet. Deposition of chlorides highly influenced the corrosion of both Galvalume and Al rather than Galfan and Zn due to the rapid local damage of the compact native thin film of Al2O3.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
Keywords
Atmospheric corrosion, NVDA tests, Zn, Al, Galfan, Galvalume, chloride, microstructure
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-232426 (URN)10.1080/02670844.2017.1305658 (DOI)000437723800001 ()2-s2.0-85016451068 (Scopus ID)
Note

QC 20180724

Available from: 2018-07-24 Created: 2018-07-24 Last updated: 2018-07-24Bibliographically approved
Szakalos, P., Åkermark, T. & Leygraf, C. (2018). Comments on the paper "Copper in ultrapure water, a scientific issue under debate" by M. Ottosson, M. Boman, P. Berastegui, Y. Andersson, M. Hahlin, M. Korvela, and R. Berger [Letter to the editor]. Corrosion Science, 142, 305-307
Open this publication in new window or tab >>Comments on the paper "Copper in ultrapure water, a scientific issue under debate" by M. Ottosson, M. Boman, P. Berastegui, Y. Andersson, M. Hahlin, M. Korvela, and R. Berger
2018 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 142, p. 305-307Article in journal, Letter (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-235892 (URN)10.1016/j.corsci.2018.02.001 (DOI)000444933400029 ()2-s2.0-85044581202 (Scopus ID)
Note

QC 20181022

Available from: 2018-10-22 Created: 2018-10-22 Last updated: 2018-10-22Bibliographically approved
Örnek, C., Liu, M., Pan, Y., Jin, Y. & Leygraf, C. (2018). Volta Potential Evolution of Intermetallics in Aluminum Alloy Microstructure Under Thin Aqueous Adlayers: A combined DFT and Experimental Study. Topics in catalysis, 61(9-11), 1169-1182
Open this publication in new window or tab >>Volta Potential Evolution of Intermetallics in Aluminum Alloy Microstructure Under Thin Aqueous Adlayers: A combined DFT and Experimental Study
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2018 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 61, no 9-11, p. 1169-1182Article in journal (Refereed) Published
Abstract [en]

In this work, first-principle density functional theory (DFT) was used to calculate the work function and Volta potential differences between aluminum alloy matrix and two intermetallic phases (Mg2Si and Al2Cu) with varying surface terminations as a function of adhering monolayers (ML) of water. The calculated data were compared with experimental local Volta potential data obtained by the scanning Kelvin probe force microscopy (SKPFM) on a commercial aluminum alloy AA6063-T5 in atmospheric environments with varying relative humidity (RH). The calculations suggest that the surface termination has a major effect on the magnitude and polarity of the Volta potential of both intermetallic phases (IMP's). The Volta potential difference between the IMP's and the aluminum matrix decreases when the surface is gradually covered by water molecules, and may further change as a function of adhering ML's of water. This can lead to nobility inversions of the IMP's relative to the aluminum matrix. The measured Volta potential difference between both IMP's and their neighboring matrix is dependent on RH. Natural oxidation in ambient indoor air for 2 months led to a nobility inversion of the IMP's with respect to the aluminum matrix, with the intermetallics showing anodic nature already in dry condition. The anodic nature of Al2Cu remained with the introduction of RH, whereas Mg2Si became cathodic at high RH, presumably due to de-alloying of Mg and oxide dissolution. The DFT calculations predicted an anodic character of both IMP's in reference to the oxidized aluminum matrix, being in good agreement with the SKPFM data. The DFT and SKPFM data were discussed in light of understanding localized corrosion of aluminum alloys under conditions akin to atmospheric exposure.

Place, publisher, year, edition, pages
Springer/Plenum Publishers, 2018
Keywords
DFT, SKPFM, Aluminum, Intermetallics, Volta potential, Aqueous adlayer
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-240239 (URN)10.1007/s11244-018-0939-9 (DOI)000435827900037 ()2-s2.0-85045260197 (Scopus ID)
Funder
Swedish Foundation for Strategic Research
Note

QC 20181219

Available from: 2018-12-19 Created: 2018-12-19 Last updated: 2018-12-19Bibliographically approved
Leygraf, C., Chang, T., Odnevall Wallinder, I., De La Fuente, D., Chico, B., Diaz, I. & Morcillo, M. (2017). Analysis of historic copper patinas 1: Influence of substrate on patina uniformity. In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017: . Paper presented at Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017, Prague Congress Centre, Prague, Czech Republic, 3 September 2017 through 7 September 2017. Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers
Open this publication in new window or tab >>Analysis of historic copper patinas 1: Influence of substrate on patina uniformity
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2017 (English)In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers , 2017Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers, 2017
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-234516 (URN)2-s2.0-85052338861 (Scopus ID)
Conference
Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017, Prague Congress Centre, Prague, Czech Republic, 3 September 2017 through 7 September 2017
Note

QC 20180907

Available from: 2018-09-07 Created: 2018-09-07 Last updated: 2018-11-09Bibliographically approved
Chico, B., Fuente, D. D., Jiménez, J. A., Chang, T., Odnevall Wallinder, I., Leygraf, C. & Morcillo, M. (2017). Analysis of historic copper patinas 2: Characterization of 400 year old patina from Royal Summer Palace in Prague. In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017: . Paper presented at Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017, Prague Congress Centre, Prague, Czech Republic, 3 September 2017 through 7 September 2017. Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers
Open this publication in new window or tab >>Analysis of historic copper patinas 2: Characterization of 400 year old patina from Royal Summer Palace in Prague
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2017 (English)In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers , 2017Conference paper, Published paper (Refereed)
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 close to 400 years of exposure to the action of the atmosphere. A wide variety of techniques have been performed, including metallographic and chemical analysis (electrogravimetry, AAS, XRF) of the copper matrix, and spectroscopic and microscopic investigations (GIXRD, 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 [Cu3(CO3)2(OH)2]; and (c) the brochantite/antlerite crystals are randomly doped with Fe and C.

Place, publisher, year, edition, pages
Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers, 2017
Keywords
Atmospheric corrosion, Characterization, Copper tile, Patina, Queen Anne's Summer Palace
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-234519 (URN)2-s2.0-85052322168 (Scopus ID)
Conference
Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017, Prague Congress Centre, Prague, Czech Republic, 3 September 2017 through 7 September 2017
Note

QC 20180907

Available from: 2018-09-07 Created: 2018-09-07 Last updated: 2018-11-09Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9453-1333

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