• Journal of Conservation Science
• /
• v.22
• /
• pp.43-60
• /
• 2008

This study is investigated the characteristics and the comparison on blackware and whiteware at Gilmyeong-ri kilns, located Poncheon-si, Geonggi province at AD 19c using scientific analysis. It is measured by scientific analysis classified as microstructure observation, physical methods which involved chromaticity, specific gravity, absorption ratio and porosity, and chemical analysis of components of body and glaze. As a result, a particle and a pore of body surface appeared differently by the degree of vitrification. In glaze, Blackware have better on good vitrification than whiteware in the microstructure observation. The physical characteristics of chromaticity, specific gravity, absorption ratio and porosity differed according to degree of vitrification rather than porcelain types. In composition, body of blackware have higher ratio of $Fe_2O_3$ and $TiO_2$ than of whiteware. Also glaze of blackware have higher ratio of $Fe_2O_3$ and $TiO_2$, and lower ratio of $SiO_2$ and $Al_2O_3$ than whiteware. Especially, blackware have higher ratio in the composition of CaO and $P_2O_5$ by which ash is used or not.

• Journal of Conservation Science
• /
• v.32 no.4
• /
• pp.549-560
• /
• 2016

The purpose of this study is to identify the material characteristics of blackwares excavated from the Bonggok kiln site in Jinan-gun, Jeollabuk-do Province, South Korea, by scientific analyses and a reproduction experiment. Scientific analyses were conducted to determine the physical properties, chemical composition and for microscopic observation of blackwares. A reproduction experiment was also conducted by producing ceramic samples with black glaze, red ocher and limestone, and then cross sections of the samples were observed. The analysis results showed that all the excavated blackwares have similar properties such as chromaticity, specific gravity, absorption factor and porosity, but there is a difference depending on the crystallization of the ceramics. Thermal analysis showed that the exothermic peak was observed at about $1200^{\circ}C$, and crystal structure analysis indicated the presence of mullite. Hence, it can be concluded that the firing temperature of the excavated blackwares was around $1100-1200^{\circ}C$. Moreover, the glaze present on these blackwares has about 22% higher $Fe_2O_3$ content than those excavated from other places; however, the former has lower CaO content. For the reproduction experiment, samples were made using limestone as a flux and red ocher as a glaze. The results show that the cross section of the glaze layer of the reproduced sample have iron crystals with dendritic structures, similar to those present in the excavated black-wares. It is assumed that such iron crystals were formed during the process of melting and solidification of the iron oxide present in the blackwares.

• Journal of Conservation Science
• /
• v.36 no.5
• /
• pp.393-404
• /
• 2020

We observed changes in the properties of the glaze layer according to the content of iron oxide and inferred the composition, content, and environment of the materials used in the past during the production process of black ware. First, experiments were conducted using different ratios of iron oxide, feldspar, calcite, and ash at different temperatures and firing environments; the characteristics of glaze were classified into five groups in the oxidation environment. Different properties were identified in the reducing environment above 1200℃. The crystal identified in the experiment was similar to the glaze characteristics in the excavated black ware. The crystal phase appeared in four groups: band shape, circular, arborescent phase, and needle crystal, depending on the change in the content of iron oxide. However, the difference in crystals did not appear significantly at high temperatures. In addition, crystals of glaze were divided into two groups depending on the component ratio. The presence or absence of feldspar is thought to affect crystallinity and amorphous iron oxide and the changes in the glaze layer changed substantially depending on the amount of iron oxide. In particular, it was confirmed that the aspects of iron oxide in the oxidation and reduction environments were different and, therefore, crystallization due to the firing environment also affected the optical characteristics.

• Journal of Conservation Science
• /
• v.36 no.2
• /
• pp.112-122
• /
• 2020

The purpose of this study was to find out the correlation through comparative analysis of used materials and manufacturing techniques such as firing characteristics for sherds excavated from celadon kiln site in Punggil-ri, Jangheung. The color difference of the sherds was very wide, and even in the microstructure of the cross section of the glaze layer and the body layer, the celadons, whitewares, blackware, and stonewares could not be characterized because they did not show distinct differences from each other. As a result of estimating the firing temperature through the analysis of constituent minerals and thermal analysis, most of them were estimated to have been fired at 1000℃, but some were fired at high temperatures above 1200℃. It was difficult to clearly distinguish between celadon and whiteware even in the major compositional content of bodies. In the statistical analysis, glaze could be classified three group according to the type of sherds, but the bodies of celadons, whitewares, and blackware classified into one similar group. It is considered that it is not more likely differences in raw materials but some ingredients were removed or added during the purification process. Conclusionally, in this kiln site was found through scientific analysis that there were technical attempts to produce various ceramics, and that the manufacturing techniques and materials of ceramics were in an early stage that was not stabilized.