Aspects of Bronze Patina and its Treatment

Organ, R. M.

doi:10.1179/sic.1963.002

Cited by 34 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Nantokite, when present, can turn into basic copper chlorides, such as atacamite, as a result of the interaction with atmospheric moisture. Such a transformation is one of the main causes of a the so-called “bronze disease” [ 32 , 41 ]. A number of publications provide indications to prepare natural and artificial patinas in the laboratory [ 42 – 47 ], but for some of the most important ones (such as those containing brochantite), good reproducibility can only be obtained after highly time-consuming ageing procedures.…”

Section: Introductionmentioning

confidence: 99%

Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

Goidanich

Gulotta

Brambilla³

et al. 2014

Sensors

View full text Add to dashboard Cite

Traditional electrochemical techniques, such as linear polarization resistance (Rp), and electrochemical impedance spectroscopy (EIS), cannot be applied to gilded bronzes, as it may not be possible to interpret the results obtained due to the bimetallic nature of the studied material. The measurement of the macrocouple current generated by the gold/bronze galvanic couple can be used as an indicator of degradation processes. Nevertheless, this measurement cannot be performed directly on the original artifacts due to the systematic presence of short-circuits between the two metals. In the present work the use of galvanic sensors is proposed as a possible solution for the monitoring of gilded bronze artefacts. The sensors have been designed to simulate real gilded bronze surfaces in terms of composition and stratigraphy and have proved to be a reliable diagnostic tool for the in situ monitoring of the rates of deterioration of gilded bronze surfaces and to test new conservation treatments. Their set-up and application is reported and their performances discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

Goidanich

Gulotta

Brambilla³

et al. 2014

Sensors

View full text Add to dashboard Cite

show abstract

“…To evaluate the archaeometric characteristics one should consider both the deterioration of physicalstructural and functional elements, as well as the degradation of chemical components that, apart from being affected by processes of monolithization, mineral-ization, segregation, and recrystallization (in the case of bronze), are also reformed structurally in the presence of Sn(IV), Pb(II), and Zn(II) hydrogels during periods with increased humidity. These films are formed on continuous layers of cuprite (Organ, 1963;Sandu, et al, 2002Sandu, et al, , 2005Sandu, 2008).…”

Section: Introductionmentioning

confidence: 99%

Influence of archaeological environment factors in alteration processes of copper alloy artifacts

Sandu

Mircea

Vasilache

et al. 2012

Microscopy Res & Technique

View full text Add to dashboard Cite

The article presents the experimental results obtained by combining noninvasive techniques (OM, SEM/EDX, XRF) to analyze three artifacts made of copper alloys discovered in a inhumation tomb (2) and in the soil profile (1) in archaeological sites from Neamt County Romania. To uncover the mechanism of alteration thereof during their longtime underground stay in specific chemical conditions and under the influence of other pedological factors, the corrosion products must be identified. The excess of the chloride ion, from burial site, disturbs the Liesegang effect, transforming the bulk in a stratified sponge structure with chlorapatite and hydroxyapatite. Some of the compounds from primary and secondary patina can be found on the surface of the bulk, as color stains. The presence of alloy components (Cu, Sn, Pb, Zn, Fe, etc.) and of the underground contamination components, allowed us to establish the origin of the ore, the manufacture technology and we identified other materials which affected the artifacts after abandonment.

show abstract

“…Finalmente, se habla de corrosión cíclica para designar la corrosión más o menos localizada, pero particularmente intensa que se produce sobre el bronce arqueológico y que puede, en caso de particular virulencia, llevar a la total disgregación de la pieza. Organ (1963), describió este fenómeno suponiendo que la etapa inicial del proceso de corrosión consistía en la formación de cloruro de cobre (I):…”

Section: C) Otros Tipos De Corrosiónunclassified

“…La descripción detallada de los procesos químicos involucrados en la corrosión de cobre y bronce permanece, pese a todo, como un tema objeto de discusión (Lucey, 1972). Como se ha señalado anteriormente, Organ sugirió que el mayor responsable de la reacción de la "enfermedad del bronce" es la hidrólisis del CuCl para dar cuprita, Cu2O (Organ, 1963), pero para otros autores (Pollard et al, 1989), la formación de hidroxicloruros de cobre (II) es el principal proceso corrosivo en ambientes salinos. Los estudios de Lewin y otros (Lewin, 1967a;Sharkey y Lewin, 1967b) sugirieron que la proporción de iones hidróxido/cloruro en solución y/o la elevada presencia de complejos de cobre/cloruro determina un mayor grado de formación de atacamita o paratacamita como productos de corrosión; de hecho, se ha señalado que incluso bajo las condiciones de Laboratorio, el modo de producción de hidroxicloruros es crítico (Tennent y Antonio, 1981).…”

Section: Examen Científico A) Técnicas De Examen No Destructivasunclassified

“…La atacamita (en ambientes marinos), la bronchantita (en la atmósfera) y la malaquita (en suelos) son los principales constituyentes de las capas de corrosión cubriendo, como se ha indicado con anterioridad, una pátina primaria de cuprita que se encuentra en contacto con el núcleo de metal (Lucey, 1972). El estaño se disuelve por lo general en el medio externo (destannificación), pero en varios casos, se han encontrado altas cantidades de compuestos de estaño en pátinas (Organ, 1963;Pollard et al, 1992).…”

Section: Examen Científico A) Técnicas De Examen No Destructivasunclassified

See 1 more Smart Citation

Estudios integrados de procesos analíticos y conservativos de bronce arqueológico. Aplicación a un casco montefortino y otros materiales afines.

Lazaro¹,

Desamparados²

View full text Add to dashboard Cite

An integrated methodology incorporating preliminary archaeometric studies, design and performance of conservative and preventive treatments, as well as the design of an expositive support for a Montefortino helmet conserved at the Museum of Requena (Valencia, Spain), is presented. It was a bronze helmet dated back at the 3rd century B.C., providing from a terrestrial archaeological context showing intense degradation caused by cyclic corrosion associated to cuprous chlorides known as "bronze disease". The object showed advanced intergranular corrosion with deep attack of nantokite and minerals of the atacamite family, giving rise to an important structural fragility. The singularity of the object either in regard to its historic and documental value as well as in regard to its problems of mechanical and physico-chemical deterioration, have been faced from an interdisciplinary perspective around three specific aspects: i) the archaeometric study, focused on the characterization of the mechanical and physico-chemical deterioration using radiographic and analytic techniques, mainly, Optical Microscopy (OM), Scanning Electron Microscopy (SEM/EDX), X-ray Fluorescence Spectrometry (XRF) and Volammetry of Microparticles (VMP); ii) structural study on the mechanical resistance of the helmet using digital modeling techniques; iii) application of chemical decloruration conservative treatments accompanied by the study of expositive systems, including the design of a specific support. The monitoring of the conservation state of the object was carried out by means of climatic control and analytical examination after seven years of Museum exposition, showing that the helmet still XII maintains an acceptable level of mechanical and physico-chemical stability.

show abstract

Aspects of Bronze Patina and its Treatment

Cited by 34 publications

References 0 publications

Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

Influence of archaeological environment factors in alteration processes of copper alloy artifacts

Estudios integrados de procesos analíticos y conservativos de bronce arqueológico. Aplicación a un casco montefortino y otros materiales afines.

Contact Info

Product

Resources

About