This study systematically analyzed the chemical composition, phase, firing temperature and atmosphere of Han Dynasty lead glazed pottery unearthed from the Yangguanzhai Site, China, through X-ray fluorescence spectrometer (XRF), X-ray diffractometer (XRD), Raman spectrometer (Raman), thermal expansion meter, X-ray photoelectron spectrometer (XPS), etc., and explored its raw material composition and firing process. The results show that the chemical composition and phase of all sample bodies are similar to those of the clay in the burial area of the Yangguanzhai site, so the raw materials used for making the bodies are all local clay. The glaze colors are divided into three types, i.e., yellow, green and yellow-green. The yellow glaze mainly uses Fe₂O₃ provided by the clay for making the body as a coloring agent, while the green glaze mainly uses CuO provided by bronze as a coloring agent. The content of Fe₂O₃ and CuO in the yellow-green glaze is between the two. Because the melting point of clay is higher than that of bronze, yellow glaze needs to increase lead-rich raw materials and reduce silicon-rich raw materials to lower the melting temperature of the glaze, resulting in yellow glaze showing the characteristic of "high lead and low silicon", while green glaze is the opposite, with yellow-green glaze lying between the two. Although there are differences in the types of colorants and glaze formulas, the samples of the three glaze colors are all fired in an oxidizing atmosphere at the firing temperatures controlled at 850-950 ℃.

In this study, we analyzed the chemical composition and phase composition of the body and glaze in 29 samples to investigate their raw materials and firing techniques by XRF, XRD, Raman spectroscopy, and other techniques.

Based on the colorimetric parameter analysis of glaze samples, they can be categorized into three types, i.e., yellow, green, and yellow-green. The saturation (C*) of yellow and yellow-green glazes exhibits a significant variation, while green glazes show a greater consistency. This variation is correlated to the types and concentrations of colorants in the glazes. The body color is uniform and stable, with coloration primarily influenced by saturation. All the body samples are colored with Fe₂O₃ and TiO₂, exhibiting the similar chemical compositions and phase characteristics. This indicates that the body material likely originates from the same type of common, easily fusible clay, presumably sourced from the Yangguanzhai site. The chemical composition of the glaze layers reveals that yellow glazes have the lowest SiO₂ content and the highest PbO content, while green glazes exhibit the opposite pattern. This may be related to coloration requirements and the fluxing effect of PbO. The coloring agents originate from bronze, and the glaze materials incorporate clay from the body production process as an iron source. The XRD patterns and Raman spectra further confirm the presence of quartz, feldspar, mica, and hematite phases in both body and glaze. The XPS analysis reveals Fe³⁺ as the predominant iron species. Combined with thermal expansion measurements indicating firing temperatures at 850-950 ℃, these results collectively confirm the samples are fired in an oxidizing atmosphere.

The lead-glazed pottery bodies of the Han Dynasty could be brick red in color, with Fe₂O₃ and TiO₂ as colorants. Their chemical composition and phase were highly consistent with the clay of the site, and the components of the bodies with different glaze colors were similar. They had the characteristics of common fusing clay, indicating that the raw materials for making the bodies were taken from the local soil and fired locally. The lead glazed pottery of the Han Dynasty haf three glaze colors, i.e., yellow, green and yellowish-green. The yellow glaze mainly usef Fe₂O₃ as the main colorant, while the green glaze mainly used CuO. The content of Fe₂O₃ and CuO in the yellowish-green glaze was between the two. Since the correlation of Fe₂O₃-TiO₂ in the body and glaze was consistent, and hematite appeared in both glazes, indicating that the clay used for making the body was used as the iron source during glaze production. There could be a positive correlation between CuO and SnO₂ in the glaze, indicating that CuO originated from bronze. Because the melting point of clay was higher than that of bronze, the required PbO content was also higher. Therefore, yellow glaze showed the characteristics of low silicon and high lead, and was prone to "silver glaze" diseases. However, the correlation between SiO₂ and Al₂O₃ in the body and glaze was inconsistent, indicating that silicon-rich raw materials such as quartz sand were added to the glaze. The lead-glazed pottery of the Han Dynasty was all fired in an oxidizing atmosphere, with the firing temperature controlled at 850-950 ℃. The analysis showed that although there were differences in glaze colors, the similar process conditions were adopted for the firing temperature and atmosphere.