Technical Notes

Lefferts, Kate C.

doi:10.2307/3258837

Cited by 4 publications

(9 citation statements)

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“…In this respect, it is noteworthy that precipitation in the cold-work-containing Head (84 HV vs. 43 HV fully annealed) was barely detectable, Fig. 8, even though the copper content was about 5 wt.% [11]. Although the Cauldron results show retained cold-work is important, it is not always needed for corrosion-induced intergranular embrittlement.…”

Section: Intergranular Corrosion and Crackingmentioning

confidence: 69%

“…For the Kaptorga, the possible contribution of the burial environment, a grave, is also considered. Tables 2 and 3 show that corrosion-induced intergranular embrittlement was observed in samples from the Cauldron, Paten, Kaptorga and Head [4][5][6][8][9][10][11]. This type of embrittlement has been attributed to segregation of copper to grain boundaries, either during cooling from final annealing during fabrication, or during long-term burial at ambient temperatures [9,[12][13][14][15].…”

Section: Survey Of the Resultsmentioning

confidence: 98%

“…Both [11], showing slightly distorted annealing twin boundaries, deformation twins, and barely detectable discontinuous precipitation of copper at grain boundaries. The black particles are probably copper oxide originating from the time when the metal was cast [11] are distinct possibilities resulting from the grave burial: besides the weight of the soil, especially on hollow artifacts like the Kaptorga, the groundwater in graves can be very saline owing to human decomposition [17]. Support for these possibilities comes from another grave burial artifact, the Khan Cup, which was highly fragmented owing to ''crystalline'' fracture [18].…”

Section: Intergranular Corrosion and Crackingmentioning

confidence: 96%

“…The Byzantine Paten (altar plate) and Romanesque Kaptorga (small container for relics and amulets) date from the 7th and 10th centuries AD, respectively. The sixth artifact is a Sasanian King's Head [11], dating from the 4th century AD. The Kaptorga and Head are the subjects of the reviewed cases mentioned above [8][9][10][11].…”

Section: The Artifactsmentioning

confidence: 99%

“…Since 1994, the NLR has investigated four cases of ancient silver embrittlement [1][2][3][4][5][6][7], one as a re-assessment [7], and reviewed two cases investigated by others [8][9][10][11]. Experience and insight gained from the investigations enables presenting the most likely explanations of embrittlement for all six cases.…”

Section: Introductionmentioning

confidence: 99%

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Case Histories of Ancient Silver Embrittlement

Wanhill

2011

J Fail. Anal. and Preven.

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This article discusses six cases of ancient silver embrittlement. The diagnostic techniques and results are surveyed, followed by the most likely explanations of embrittlement. There are two basic types of embrittlement: corrosion-induced, and microstructurally induced, which can act synergistically. Corrosion-induced embrittlement takes several forms, including what appears to be intergranular and transgranular stress corrosion cracking. The main intrinsic factor facilitating corrosion-induced embrittlement is retained cold-work in the silver. Microstructural embrittlement is characterized by intergranular fracture, most probably due to low-temperature segregation of lead to the grain boundaries. Knowledge of the details of embrittlement can be essential for optimizing the restoration and conservation of damaged artifacts.

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Section: Intergranular Corrosion and Crackingmentioning

confidence: 69%

Section: Survey Of the Resultsmentioning

confidence: 98%

Section: Intergranular Corrosion and Crackingmentioning

confidence: 96%

Section: The Artifactsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Case Histories of Ancient Silver Embrittlement

Wanhill

2011

J Fail. Anal. and Preven.

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Significance of Discontinuous Precipitation of Copper in Ancient Silver

Wanhill

2012

Metallogr. Microstruct. Anal.

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Discontinuous precipitation of copper has been held responsible for much of the embrittlement of ancient silver objects. The detailed characteristics of this precipitation have been suggested as possible indicators of an object's age and authenticity. These proposals are considered in the light of metallographic and analytical studies of several embrittled artifacts. These studies indicate that discontinuous precipitation is much less significant for embrittlement than residual stresses due to retained cold-work and externally applied stresses due to burial, and that the precipitation characteristics cannot be used for authentication.

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Prüfung der coccidiostatischen Wirksamkeit von Coyden 25®1 auf Eimeria tenella durch quantitative Bestimmung der Blutmenge in den Blinddärmen mit Hilfe Fe59-markierter Erythrozyten

Ënigk

Schanzel

Hazra

2010

Zentralblatt Für Veterinärmedizin Reihe B

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Zusammenfassung An 50 Küken wurde die Wirksamkeit von Coyden 25 (Dow Chemical Company) in Dosen von 80 mg, 100 mg und 125 mg/kg Futter auf die experimentelle Infektion mit Eimeria tenella2) geprüft. Als Prüfmethode verwendeten wir die Ermittlung der in den Blinddärmen vorhandenen Blutmenge. Die Messung des Blutes erfolgte durch Markierung der Erythrozyten mit Fe59, das allen Küken im Alter von 14 Tagen intraperitoneal verabreicht wurde. Die Dosis je Tier betrug etwa 1 μCi Fe59‐zitrat. Im Alter von 3 Wochen erfolgte die Infektion der Küken mit Ausnahme einer Kontrollgruppe mit je 20 000 E. tenella‐Oocysten. Fünf Tage später töteten wir die Tiere. Gemessen wurde die Aktivität der Blutprobe und der Blinddärme von jedem Küken. Die Aktivität der Caeca wurde auf die Aktivitàt von 1 g Blut umgerechnet, so daß das in den Blinddärmen vorhandene Blut quantitativ bestimmt werden konnte. Die Zugabe von 125 mg Coyden 25 zu 1 kg Fertigfutter erwies sich als voll wirksam, die niedrigere Dosis jedoch als nicht zuverlässig. Summary Demonstration of the coccidiostatic effectiveness of Coyden 25® on Eimeria tenella by quantitative determination of the blood content in the caecum with the help of red cells labelled with Fe59 Using 50 chicks, the effectiveness of Coyden 25 (Dow Chemical Company) at levels of 80, 100 and 125 mg./kg. of food was studied in experimental infection with Eimeria tenella. The method consisted in determining the amount of blood present in the caeca, measured by labeling with Fe59 which had been injected intraperitoneally in all the chicks when 14 days old, the dose per chick being about 1 μ, Ci Fe59 citrate. At the age of three weeks all the chicks except the control group were infected with 20,000 oocysts of E. tenella and the birds were killed five days later when the activity in the blood and the caeca was measured in each chick. The activity in the caecum was expressed per gramme of blood so that the amount of blood in the caece could be quantitatively determined. A dosage of 125 mg. Coyden 25 per kg. of prepared food was proved to be fully effective, while the smaller doses were not completely effective. Résumé Test de l'activité coccidiostatique du Coyden 25® sur Eimeria tenella par détermination quantitative du sang présent dans les caecums à l'aide d'érythrocytes marqués au Fe59 On teste l'activité du Coyden 25 (Dow Chemical Company) à des doses de 80 mg, 100 mg et 125 mg/kg d'aliments sur une infection expérimentale par Eimeria tenella. La méthode consiste à déterminer la quantité du sang présente dans les caecums. La mesure du sang se fait par marquage des érythrocytes au Fe59, que l'on administre par voie intrapéritonéale à tous les poussins âgés de 14 jours. La dose par animal est de env. 1 μgCi de citrate de Fe59. A l'âge de 3 semaines, on procède à l'infection de tous les poussins, à l'exception d'un groupe témoin, avec 20 000 oocystes d'E. tenella par poussin. Cinq jours plus tard, on sacrifie les oiseaux. On mesure l'activité du prélèvement sanguin et des caecums de chaque poussin. L'activité...

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Technical Notes

Cited by 4 publications

References 0 publications

Case Histories of Ancient Silver Embrittlement

Case Histories of Ancient Silver Embrittlement

Significance of Discontinuous Precipitation of Copper in Ancient Silver

Prüfung der coccidiostatischen Wirksamkeit von Coyden 25®1 auf Eimeria tenella durch quantitative Bestimmung der Blutmenge in den Blinddärmen mit Hilfe Fe59-markierter Erythrozyten

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