• 보존과학연구
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• s.14
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• pp.1-34
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• 1993

1. Metallurgical Properties of Iron artifacts excavated from Yangju-Mountain fortress were studied for the scientific conservation and metallurgical history of ancient Iron artifacts.2. Iron artifacts form Yangju-Mountain fortress were found to be the products of having well-established Carburizing and remelting technique in that period.3. These artifacts seem to be manufactured from very pure ores, because very pure ferrite structure and low impurity.4. Especially evidence of very suitable carburizing technic well-established and usealloying method of Fe-C system on purpose were found.5. Cast iron artifacts were found to be eutectic composition (4.31%) having lowestmelting point in Fe-C system.

• Journal of Conservation Science
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• v.18 s.18
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• pp.33-50
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• 2006

Around Yeongsan river basin, there are Yeongkwang Gundong, Muan Inpyeong Tombs, Muu Gusan-ri Tombs and Hampyeong Guksan remain from which a lot of iron artifacts were excavated. Among them, 6 iron artifacts were chosen, and their microstructures were analyzed. As a result, Iron artifacts were produced sponge iron by the low temperature reduction process and a part of microstructure have the possibility that steel made by decarburizing. And also, by tempering the parts which need high strength, the iron artifacts had high strength and by distributing the weakness of the tempered structure to the nearby untempered parts, their breaking was prevented and they had the durability. These skills were used then. Especially these skills were found to be used in the 2nd century by high skilled people because an iron axe excavated at Yeongkwang Gundong of 2nd century by the historical record showed that the skill was used. Also microstructures were found to show the possibility that the iron technology was inherited to the late 5th century. When producing iron artifacts made of sponge iron containing small amount of carbon, that was made by the production process repeating molding, carburizing, heat treatment and hammering.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1619-1625
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• 2021

This paper demonstrates the possible nondestructive analysis of iron artifacts' metallurgical characteristics using neutron imaging. Ancient kingdoms of the Korean Peninsula used a direct smelting process for ore smelting and iron bloom production; however, the use of iron blooms was difficult because of their low strength and purity. For reinforcement, iron ingots were produced through refining and forge welding, which then underwent various processes to create different iron goods. To demonstrate the potential analysis using neutron imaging, while ensuring artifacts' safety, a sand iron ingot (SI-I) produced using ancient traditional iron making techniques and a sand iron knife (SI-K) made of SI-I were selected. SI-I was cut into 9 cm², whereas the entirety of SI-K was preserved for analysis. SI-I was found to have an average grain size of 3 ㎛, with observed α-Fe (ferrite) and pearlite with a body-centered cubic (BCC) lattice structure. SI-K had a grain size of 1-3 ㎛, α-Ferrite on its backside, and martensite with a body-centered tetragonal (BCT) structure on its blade. Results show that the sample's metallurgical characteristics can be identified through neutron imaging only, without losing any part of the valuable artifacts, indicating applicability to cultural artifacts requiring complete preservation.

• 보존과학연구
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• s.22
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• pp.115-132
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• 2001

No. 3 Tomb of Bogam-ri, in Naju City, Chollanam-do Province, was a site excavated and inspected from 1996 to 1998 and had a various grave forms, including jar-coffins, stone-chambers and stone-cists. Although most of the metal artifacts excavated from it were severely corroded, we could implement microstructure investigation by collecting samples from the iron axes, iron coffin-nails and iron clamps in which the metal parts were remained. The metal structures were inspected by using metallographic microscope and SEM, and fine components analysis was implemented by ICP. To examine the hardness differences in accordance with the structure distribution, we measured the hardness by structures with Vickers hardness testing machine. As a result of the metal structure inspection, most of them were pure iron, ferrite, and also pearlite, cementite and widmannstaten structures were displayed. We could confirm carbonization was formed on the surface of the iron axes-B, iron coffin-nails-B, and iron clamps-A. There was no carbonization in the rest of the artifacts, and it is not certain that whether the carbonized parts were peeled off through extreme corrosion or they were not carbonized when they were made. In the particular part of a blade, the quality of the material was strengthened through processing. Due to the processing re-grain was caused and fine grain particles were formed. As a result of the ICP component analysis, there were no addition atoms because pure irons were used as materials. In the mean time, No. 17 jar-coffin where the iron axes-A are excavated, is chronologically ordered as from the late-fourth century to the mid-fifth century, and No. 1 and No. 2 stone chambers, where the rest of the artifacts were excavated, as the early-sixth century. It was difficult to relate the periodic differences with the manufacture technique artifacts which we inspected because there were no distinct characteristics of the manufacture technique of the metal structures and it is impossible to conclude the artifacts and sites are at the same period although their periods are different.

• Journal of the Korean institute of surface engineering
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• v.40 no.1
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• pp.44-56
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• 2007

Excavated archaeological iron artifacts are usually conducted the conservation treatment for removal of chloride ions in the corrosion products. However, some iron artifacts are corroded again even after the conservation treatment due to unremoved chloride ions. Therefore, it is important to prevent desalinized artifacts from the occurrence of corrosion after the treatment. In this paper, we investigated the characteristics of corrosion products on salinized iron artifacts and evaluated the variety of desalination methods such as autoclave, intensive washing and NaOH. It was also found that ${\beta}-FeOOH$ (Akaganeite) played an important role on the occurrence of corrosion and the treatment for removal of chloride ions. The extents of desalination were compared between the desalination methods. Results showed that the autoclave method represented the highest efficiency for desalination while the intensive washing method was the lowest.

• 보존과학연구
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• s.24
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• pp.187-213
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• 2003

Sungseonsa Temple site in Chungju city in Chungcheongbuk-doProvince is written in "Goryeosa" as a building for Queen Sinmyeongsunseong, the mother of Gwangjong in AD 954 in Goryeo Dynasty. The museum in Chungcheong University takes charge of the excavation for 3 times from 2000 to 2002 and identified that its construction was carried out till Joseon Dynasty. Among the iron artifacts from the first excavation such as a weeding hoe, a hand knife, a lock, two nails and a plow which had conservation treatments, the sample was collected. Its micro-structure and method of manufacture were investigated. Excavation report for those artifacts has not published yet, therefore, the date of each artifacts is not clearly confirmed. The samples were collected from each part of the objects and then embedded in epoxy resin and etched with nitric acid. The examination of its microstructure is carried out under the microscope and the hardness values were measured by Vickers hardness tester. From the results, some artifacts show different manufacture method sin the each parts. The forming processes of the iron weeding hoe and the iron sickle are similar but the blade of iron weeding hoe was strengthened by carbonization whereas the blade of the iron sickle was done by quenching. The hand knife and the nails were produced through almost same methods and shows similar microstructures. The hand knife seems to be made by repeated beating and folding in low temperature resulting in fine crystallization, but the nail shows large crystallization due to processes in high temperature. Lock is made of white cast iron, that does not show any heat treatment.

• 보존과학연구
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• s.13
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• pp.37-58
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• 1992

Iron artifacts from Busǒ Sansǒng inffered to late Baikjae periodwere studied on the aspects of metallugy. These materials were the largest size ever since excavated. From the analytical results these artifacts were found to be pureiron system without impurities or hypo-eutectoid steel system in below 0.3% in carbon contents. From the content of phosphorus in the range of 0.03∼0.05% as aim purity it was shown that charcoal were used for making these iron artifacts from sponge iron not fusion method. By observing metallugical structure it was found that iron artifacts was manufactured by repetitive folding and hammering forging method and some by heating method for adding carbon with cool water. This method were to improve the quality of the soften steel to harden one. In addition to those above repetitive hammering method eliminated the nonferrous materials such as slag inclusion and remained relatively pure ferrite.

• 보존과학연구
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• s.19
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• pp.109-132
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• 1998

According to excavation of Imdang site, these sites were excavated place to a various of sites from Early lron period to the Koryo Kingdom. Artifacts to be conserved were excavated from A, D and E district. Metal artifacts were excavated from D and E district and lacquer ware artifacts were excavated from Adistrict. Metal artifacts including lacquer ware iron sword, imitative bronze mirror, Osujen and bronze artifact with letter and so on. Bronze artifacts were covered with soil and rust and performed consolidation after passivation treatment with Benzotriazole solution. Also, iron artifacts performed desalting treatment with 0.1M sesquicarbonate solution. After desalinization, adhesive of these artifacts were processed with Araldite(rapid type) after consolidation with20%∼30% NAD-10 solution. Lacquer ware artifacts remained fragments of lacquer to be all corroded and soiled. Therefore these artifacts retained its original form. Fragments of lacquer joined with Caparol 1%∼3% solution and the soil of relics coated with PSNY 3%∼6% solution. There were many kinds of lacquer were. Lacquer ware artifacts presumed to a string instrument that provide important clues for lacquer ware research. As for lacquer fragments inquire, paints grain size were $2∼5\mum$ and conformed to vanished three times.

• Journal of Conservation Science
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• v.29 no.4
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• pp.297-309
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• 2013

Iron objects become corroded at fast speed from the moment when they are excavated, so it is needed to control corrosion through processes of conservation treatment. However, re-corrosion mostly takes place in excavate iron objects, although they have already gone through the process of conservation treatment, and it is more difficult to carry out the second conservation treatment of re-corroded excavated iron objects than the first conservation treatment, and it requires a longer period of time to treat them as well. In this study, aims to discover factors of re-corrosion by scientifically analyzing corrosion products generated during the process of storage after the process of conservation treatment. The finished on conservation treatment of the iron artifacts, which were unearthed from three ancient site in Gyeongju by using the same conservation method between 2002 and 2009, re-corrosion condition observed on the packaging-iron artifacts. Focused on 9 target forged iron artifacts among them, this study analyzed the physical changes by mass measurement, naked-eye and microscopic observations and the chemical changes by SEM-EDS, XRD, IC and ICP analysis. The results show that the yellowish brown corrosion products formed on the facing surface of part dropped from the artifacts had different associated forms but acicular shape. In addition, the acicular shape became clearer as the color changed from red to yellowish brown. According to the process when the conservation treatment was completed, the mass of the artifacts increased in proportion to the corrosion products and the chloride ion ($Cl^-$) concentration had a tendency to increase relatively. ${\beta}$-FeOOH (akaganeite) was confirmed in the XRD analysis for the corrosion products of all the collected samples. As a result of ICP analysis, $Na^+$ and $Ca^{2+}$ components were confirmed.

• Conservation and Restoration of Cultural Heritage
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• v.1 no.1
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• pp.9-22
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• 2012

The most widely excavated iron artifacts used as weapons or farm tools from central southern regions of Korea were subjects of non-metallic inclusion analysis through metallographic examination, microhardness measurement, and scanning electron microscopy with energy dispersive X-ray spectroscopy. Through metallographic interpretation and study of the analyzed results, the steel manufacturing and iron smelting using heat processing in the iron artifacts excavated from the central southern region of the ancient Korean peninsula was studied, and the analysis of the non-metallic inclusions mixed within the metallic structures was interpreted as the ternary phase diagram of the oxide to infer the type of iron ores for the iron products and the temperature of the furnace used to smelt them. Most of the ancient forged iron artifacts showed $Al_2O_3/SiO_2$ with high $SiO_2$ contents and relatively low $Al_2O_3$ contents for iron ore, indicating t hat for $Al_2O_3$ below 5%, it is presumed that magnetic iron ores were reduced to bloom iron (sponge iron) with direct-reduction process for production. The temperature for extraction of wustite for $Al_2O_3$ below 1% was found to be $1,020{\sim}1,050^{\circ}C$. Considering the oxide ternary constitutional diagram of glassy inclusions, the steel-manufacturing temperature was presumed to have been near $1,150{\sim}1,280^{\circ}C$ in most cases, and minimum melting temperature of casting iron part excavated in Daeseong-ri. Gyeonggi was near $1,400^{\circ}C$, and it is thought that hypoeutectic cast iron of about 2.3% carbon was casted and fragility of cast iron was improved by decarburizing in solid state.