• Journal of Conservation Science
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• 제36권4호
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• pp.296-305
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• 2020

Konbaung Dynasty was the last unified dynasty that ruled Myanmar from 18^th to 19^th century. During this time Buddhist art flourished in Myanmar due to the interest of the rulers toward their traditional culture. Metal decorative artifacts in the 18^th century are classified into structures and Buddha statues. They are further subdivided into gilt-bronze and bronze objects, depending on their material component. Three-dimensional gilt-bronze decorative artifacts were cast with a brass alloy of Cu-Zn-Sn-Pb and their surfaces were gilded with extremely thin gold leaves (less than 1 ㎛ in thickness). The gilded layer approximately comprised 10 wt% silver in addition to the main element, gold. The lack of Hg in the gilded layer, indicated that the amalgam gilding technique was not applied. The analysis results indicated that the lacquered gilding technique was applied to the objects. Bronze decorative artifacts without gilding were cast with materials containing Cu-Sn-Pb. The bronze pavilions and bronze Buddha staues were crafted using the same alloy of high-tin bronze, which approximately contained 20 wt% Sn. No heat treatment was applied to reduce the brittleness of the objects after they were cast with a large amount of Sn. The most significant difference between the gilt-bronze and bronze decorative artifacts lie in their elemental compositions. The gilt-bronze decorative artifacts with their gilded surface were manufactured using brass containing zinc, while the unplated bronze decorative artifacts were composed of bronze containing tin. Artifacts of the same type and size are classified differently depending on the materials utilized in the surface treatment such as gilding.

• Journal of Conservation Science
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• 제26권2호
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• pp.109-120
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• 2010

Four gilded bronze objects and a gilded silver object were examined for elemental diffusion between the gilding layer and the mating matrix. The gilded bronzes consist of three objects from three different historical periods, the Korean Three Kingdoms period, the Koryo and the Choseon periods and one from an unknown period. The gilded silver was from the Koryo period. The amalgam process seems to have been the major technique employed for all of them in gilding. The occurrence of substantial diffusion was observed in all but the anonymous object, particularly in the Choseon artifact where evidence was found that the diffusion phenomenon was intentionally utilized in gilding. The gold content in the gilded bronzes decreases gradually from surface to interior while the copper content increases to the interior, making it difficult to locate the boundary between the gilding layer and the matrix. This gradual change in composition must have resulted from elemental diffusion at elevated temperatures. The oxygen content negligible in the gilding layer precludes the possibility of corrosion being responsible for the varying composition. It is observed that non-uniform diffusion caused variation of colors in the surface of gilded bronzes. The change of colors induced by diffusion, which is always accompanied by the unique surface morphology and chemical compositions, is distinguished from the color change by corrosion. In the gilded silver object, diffusion of mercury was observed along with that of gold and silver.

• Journal of Conservation Science
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• 제35권3호
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• pp.187-196
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• 2019

Bronzes excavated from a Gulsansa temple site in Gangneung were investigated in order to study the production of technology and provenance in this area. The bronze artifacts were discovered to consist of copper-tin or copper-tin-lead alloys using chemical analysis(EDS and EPMA). The excavated bronzes were manufactured using a casting or hammering process, and a bronze belt was gilded with gold foil. The provenance of 25 bronzes was studied using lead isotope analysis(TIMS and LA-MC-ICPMS). The results reveal the use of raw materials found near the excavated site. The object of this study was to investigate the manufacturing techniques and provenance in Gangneung without the need for a lot of data. Our results will contribute to the study of Gulsansa and bronze artifacts in Goryo(12-13th century).

• Journal of Conservation Science
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• 제27권1호
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• pp.1-11
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• 2011

For the silver artifacts in the Koryo Dynasty excavated from Neungnae-ri Ganghwa island, the metallographic section analysis and hardness and chemical analysis were conducted. After making samples in the similar ratio of the composition concentration, the changes of the microstructure were checked according to the working method and temperature. The results show that those silver artifacts are Au-Cu alloys with 2 to 6 % of Cu. From the results it is judged that Cu was artificially alloyed with them to keep the proper hardness and identified that they were gilded by the amalgamation process seeing that mercury was included at the guilt layer. Also the porous texture on the surface of them could be formed at over $400^{\circ}C$, therefore, it is assumed the hot working or heat treatment at over $400^{\circ}C$ were performed. In silver artifacts made by the relief and repousse, they have the similar composition analysis to other 7 artifacts but the hardness is lower than pure silver. Consequently from differences in the hardness, it can be inferred that the low hardness of silver artifacts is concerned with manufacturing techniques.

• Journal of Conservation Science
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• 제28권1호
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• pp.29-37
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• 2012

This study discusses a mercury amalgam gilding technique and examines how the color, surface and section of the gilt layer changes as the condition of heat treatment with mercury amalgam gilt object is changed. Some previous studies have mentioned reasons for various colors on gilt bronze artifacts depending on gilding manufacture and environment. However, reason for reddish color with gold on the artifacts' surface brought on high temperature corrosion has yet to be discussed and analyzed. A methodology was found in representing the mercury amalgam gilding technique and heat treatment test. According to the result of the heat treatment test, in the conditions of higher temperature and longer time, the oxidized layer on the gilt layer was distributed more widely and in the part when the oxide layer was eliminated, the gilt layer with a reddish color was observed. Moreover, in the surface observation of the specimen on which yellow and reddish colors were agitated, the changing aspects of its surface condition differed by colors. When investigated the section, it was observed that the void density and size became larger. After a test, the surface components changed; the temperature of heat treatment increased, component ratio of Hg and Au decreased gradually but component ratio of Cu increased. In regard to the gilt layer, as the time was longer and the temperature became higher for the heat treatment, the component ratio of Au and Cu by layers tended to change in inverse proportion. It is concluded that gilding techniques and the burial environment can make a difference in the surface color of the gilt layer on the gilt bronze artifacts, the high temperature corrosion that occurs by heat after they are manufactured is also one of the factors that affects their surface color.

• Korean Journal of Heritage: History & Science
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• 제54권1호
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• pp.4-17
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• 2021

This study analyzed 19 samples of harness fittings and pendants, which were excavated in Tomb No. 15 in Songhyeon-dong, Changnyeong. Harness fittings and pendants are used for ostentation, rather than practicality, and were excavated from ancient tombs in Gaya culture. So, they are considered artifacts that compare the production techniques and raw materials. This study aimed to examine the production techniques and provenience studies of Bihwa Gaya, which is estimated to be from the 5th to 6th centuries. According to the research, harness fittings were made of pure copper and were gilded with Au·Ag alloys on their surfaces. Hg was detected together and plated with a mercury amalgam method. As a result of the pendant (fish scales-pattern, oval and fish-tail shape), analysis showed that Fe in the background metal, Cu in the middle layer, and Au and Ag on the surface were the main components. The method of adhesion between Cu and Au·Ag gilded layers are plated by a mercury amalgamation method. So, it was identified by the gilt-iron·gold·bronze technique. Since the pendant (heart shaped) is found to be the main component of Fe in the background metal and Ag in the surface layer, the metal was made gilt-iron·silver technique. The background metal and gilding were additionally fixed using a rivet. The raw materials of 3 harnesses excavated from Changnyeong are plotted in zone 2 in the southern Korean Peninsula. And 16 harnesses were plotted in Chinese copper ore by Mabuchi Hishao in the Chinese Peninsula.

• Conservation Science in Museum
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• 제21권
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• pp.53-66
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• 2019

This study describes the processes undertaken for the conservation treatment of metal artifacts excavated in Hasong-ri, Yeongwol, Gangwon-do and the results of the related surface composition analysis. X-ray fluorescence analysis (XRF) was applied to analyze the surface composition of a small gilt-bronze wind chime, two clappers, and a small gourd-shaped bronze bottle. The gourd-shaped bronze bottle was investigated using radiography to examine its internal structure. The wind chime and clappers were excavated from the same location. A gilt layer was identified on the wind chime, but surface corrosion made it difficult to identify any such layers on the clappers. The element analysis revealed that the wind chime was made of bronze in a Cu-Sn-Pb ternary system and was gilt-plated using mercury amalgam. The clappers were made from copper with a small amount of gold detected, but did not show any evidence of mercury. Since a thick corrosion layer was affixed to the surface of each clapper, it was impossible to identify the surface composition and determine if the clappers had been gilded. It is possible that the gold detected from the clappers was a foreign substance or had detached from the giltbronze wind chime buried alongside them. The small gourd-shaped bronze bottle was investigated through surface element analysis and radiography to verify if it was a type of silver bottle used as currency during the Goryeo dynasty. The radiography photography identified that a small hole in the middle of the base had been stopped up. The general surface analysis did not detect silver, which suggests that the bottle was made of bronze instead and was not one of the silver bottles used as a means of currency.