The Stabilization of ‘Active’ Bronze and Iron Antiquities by the Use of Sodium Sesquicarbonate

Oddy, W. A.; Hughes, Michael J.

doi:10.1179/sic.1970.017

Cited by 14 publications

(13 citation statements)

References 3 publications

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“…They are usually stored in tap water or a sodium sesquicarbonate solution. [29][30][31] Several other methods for stabilizing corroded copper alloys are used as well, such as washing the objects in alkaline dithionite, in citric acid inhibited with thiourea, or in aqueous acetonitrile. However, the use of tap water or a sodium sesquicarbonate solution remains the most common method, since this procedure proves to be the least damaging to the patina.…”

Section: Monitoring the Transformation Of Nantokite To Cupritementioning

confidence: 99%

Cell for Simultaneous Synchrotron Radiation X-ray and Electrochemical Corrosion Measurements on Cultural Heritage Metals and Other Materials

Dowsett

Adriaens

2006

Anal. Chem.

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We describe the construction of an electrochemical cell of the Bragg type suitable for in situ synchrotron X-ray measurements on rough, heterogeneous metals such as cultural heritage alloys and simulants with corroding or passivated surfaces. The cell features a working electrode, which may be moved under remote control from a position close to an X-ray window to full immersion in the electrolyte. A pocket of electrolyte in contact with the bulk can be maintained on the working electrode surface at all times. Its thickness (typically 100-200 µm) can be controlled by adjusting the working electrode position and, independently, altering the conformation of the X-ray window with hydrostatic pressure. Alternatively, the electrode may be lowered into the bulk of the electrolyte. Early results from the cell showing a time-resolved study of the reduction of nantokite to cuprite in sodium sesquicarbonate, accompanied by corrosion potential measurements obtained in parallel, are presented here.The application of electrochemical techniques for the stabilization, cleaning, and protection of metallic cultural heritage objects from silverware to battleships 1-6 is proving to be extremely effective, and research in this area has increased significantly in the past 10 years. The value and uniqueness of some of the objects involved, together with other issues such as their location, means that all conservation treatments must be thoroughly understood and tested, preferably before first use. The consequences of failure range from the loss of an irreplaceable museum object to serious environmental damage (e.g., in the case of fuel leakage from a sunken World War 2 battleship). 7 In addition, there is a need for fully qualified but simple in situ monitoring techniques that can be used by conservators, for example, corrosion potential (E corr ) measurements on artifacts stored in stabilizing media (such as marine objects immersed in sodium sesquicarbonate solution). 8,9 There exist many techniques that can be used for the ex situ study of real and simulated surfaces (e.g., analytical electron microscopy, various electron spectroscopies, mass spectrometric techniques 10-13 ). In most cases, these require that the sample is placed in an untypical environment such as a vacuum and the relationship between such measurements and the surface chemistry in the native state is rarely established. Moreover, it is only recently that it has become possible, using these techniques, to observe reactions at the liquid-metal interface as they occur. 10 In 1980, Fleischmann et al. described the first in situ observation of electrochemical reactions at the liquid-solid interface using X-ray diffraction (XRD). 15 A few years later, Fleischmann et al. published some of the earliest designs for electrochemical cells for use with a variety of synchrotron X-ray (SR-X...) techniques. 16 Since then, the use of SR-XRD, synchrotron X-ray absorption spectroscopy (SR-XAS), and electrochemistry has been described by a number of authors, 17-25 many of who...

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Section: Monitoring the Transformation Of Nantokite To Cupritementioning

confidence: 99%

Cell for Simultaneous Synchrotron Radiation X-ray and Electrochemical Corrosion Measurements on Cultural Heritage Metals and Other Materials

Dowsett

Adriaens

2006

Anal. Chem.

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“…These include the sodium sesquicarbonate treatment [3], exposure to vapours of ammonia [4], or filling the cavities with silver oxide paste after removing the disease mechanically [5]. These include the sodium sesquicarbonate treatment [3], exposure to vapours of ammonia [4], or filling the cavities with silver oxide paste after removing the disease mechanically [5].…”

Section: Cu2c12 + [O] -Cu20 + 2cucl2mentioning

confidence: 99%

A Novel Method for Conservation of Copper-Based Artifacts

Ganorkar¹,

Rao²,

Gayathri³

et al. 1988

Studies in Conservation

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Maney Publishing and International Institute for Conservation of Historic and Artistic Works are collaborating with JSTOR to digitize, preserve and extend access to Studies in Conservation.Abstract-A new method was developed for removing bronze disease and for the conservation of ancient copper and copper-based artifacts. An organic compound, 2-amino-5-mercapto-1,3,4thiadiazole was found to be a good inhibitor. It removes the bronze disease completely and forms a protective polymeric complex layer on the surface of the metal artifacts, which is resistant to corrosion.

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“…In the presence of moisture and oxygen, copper chlorides are hydrolyzed to form hydrochloric acid and basic cupric chloride. The hydrochloric acid in turn attacks the uncorroded metal to form more cuprous chloride [1].…”

Section: Introductionmentioning

confidence: 99%

“…The use of sesquicarbonate solutions has become a standard element in the stabilization of corroded cupreous objects recovered from marine environments. When bronzes or other alloys of copper are placed in a 1 wt% solution of sodium sesquicarbonate (NaHCO 3 .Na 2 CO 3 ), it is reported that the hydroxyl ions of the alkaline solution react chemically with the insoluble cuprous chlorides to form cuprous oxide and to neutralize any hydrochloric acid by-product formed by hydrolysis to produce soluble sodium chlorides [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Insights into electrolytic stabilization with weak polarization as treatment for archaeological copper objects

et al. 2006

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Immersion of corroded copper artefacts in dilute sodium sesquicarbonate solution is a well-recognized stabilization technique-especially in the conservation of objects recovered from marine environments and therefore saturated with chlorides. Here we describe three linked experiments performed to investigate a variation on this treatment, involving the application of a low potential to the artefact in order to drive the chloride extraction process. This includes a new spectroelectrochemical approach which allows 2-D pseudorandom X-ray reflection diffraction patterns to be obtained without interrupting the reaction in solution. Experiments were carried out on synthetically produced chloride layers on copper (nantokite and atacamite). We show that a thick chloride layer is, in general, replaced by a thin cuprite layer through a mechanism which involves detachment of the chloride crystallites from the surface prior to dissolution.

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The Stabilization of ‘Active’ Bronze and Iron Antiquities by the Use of Sodium Sesquicarbonate

Cited by 14 publications

References 3 publications

Cell for Simultaneous Synchrotron Radiation X-ray and Electrochemical Corrosion Measurements on Cultural Heritage Metals and Other Materials

Cell for Simultaneous Synchrotron Radiation X-ray and Electrochemical Corrosion Measurements on Cultural Heritage Metals and Other Materials

A Novel Method for Conservation of Copper-Based Artifacts

Insights into electrolytic stabilization with weak polarization as treatment for archaeological copper objects

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