Mössbauer study of the black-glazed Jian bowl in the Song dynasty

Jian ware, also known as “Tenmoku,” is one of the famous black-glazed porcelains in China. It was highly coveted in the Song dynasty (960–1279 AD) and was also a tribute to the royal family. The black-glazed Jian wares are mainly made from iron-rich clay. In this study, black-glazed Jian bowl sherds excavated from the Song strata of Jian kiln sites were adopted as test samples. The iron phase and firing techniques of the black-glazed Jian bowl from the Song dynasty were analyzed and discussed through Mössbauer spectroscopy on the both of body and glaze, together with X-ray diffraction and scanning electron microscopy. According to the different iron content and the unique iron oxide phase reflected in the Mössbauer spectra, we analyzed the firing atmosphere, temperature, and other conditions of the ancient Jian bowl, as well as the difference of iron phase between the body and the glaze layer due to the collapse of the silicate framework. It provides new ideas for deciphering the firing technology and improving the synthesis of ancient black-glazed Jian wares.     

Imitation of ancient black-glazed Jian bowls (Yohen Tenmoku): Fabrication and characterization

Yohen Tenmoku is a kind of famous black glazed Jian bowls made in ancient China. Here, imitations of Oil Spot Yohen Tenmoku were sintered at about 1280 °C in a shuttle kiln with oxygen flow. Microstructure characteristics and chemical compositions were investigated by a combination of X-ray based and photon based characterization methods. The results showed that quartz and mullite were the main crystalline phases in the bowl bodies. At the glaze surface of the bowl, the highly reflective red iridescence and the silvery appearance of Oil Spot patterns were resulted from the precipitation of hematite (α-Fe₂O₃) crystals. A detailed study has revealed the partially ordered microstructure within one Oil Spot which produced the striking optical effects.     

Degradation mechanism of the Ru wares unearthed from the Qingliangsi site in Henan,China

The Ru kiln is a famous kiln that originated in the Northern Song Dynasty (960–1127 CE) in China. After nearly a thousand years of degradation, many ‘white spots’ have appeared on the Ru glazes, which have seriously damaged the visual aesthetic. Energy-dispersive X-ray fluorescence spectroscopy (EDXRF), X-ray diffraction analysis (XRD), optical microscopy (OM), scanning electron microscopy-energy dispersive spectrometry (SEM–EDS), Raman spectroscopy, and angle-resolved spectrum system were used to systematically investigate the composition, microstructure, and degradation morphology of the Ru ware. The degradation mechanism of the Ru glaze was investigated, showing that the heterogeneity of the glaze microstructure resulted in different degradation morphologies. The weakest part determined the overall corrosion resistance. Fine crackles of the glaze provided a fast path for corrosion. The special soil environment at the Qingliangsi site was a key influencing factor leading to the ubiquitous and severe degradation of the Ru wares. The microstructure degradation caused by chemical corrosion provided complex light-reflecting interfaces, leading to the formation of ‘white spots’ on the surface. Combined with the influence of exotic contaminants, the color and texture of the Ru glaze significantly changed, and the appearance quality seriously declined.     

用PIXE技术测定古代建窑‘供御’和‘进盏’瓷片的主量,痕量化学组成

首次应用质子激发Ｘ荧光分析（ＰＩＸＥ）技术对古代建窑‘供御’和‘进盏’款天目瓷的主量、痕量化学组份进行测定,应用模式识别方法将测量结果与古代吉州天目瓷、耀州天目瓷作比较。同时对建窑天目瓷胎和釉的均匀性进行了分析。为恢复和重现古代建窑天目瓷的各类产品奠定了基础     

Characterization of the rare oil spot glazed bowl excavated from the Xiao kiln site of north China

“Oil spot”, which is a famous decorating technique of black glazed porcelain in the Song Dynasty, is a representative handicraft of Jian bowls found in the Jian Kiln in southern China. An oil spot black glaze bowl was found in the Xiao Kiln in Anhui Province in a field investigation, which is the first time that this pattern of porcelain was found in this area. Various techniques were performed on this bowl and on another black glaze porcelain piece from the same archaeological layer, including optical microscopy, scan electron microscopy, XRF, Raman spectromicroscopy and XRD. The results show that its main chemical composition is similar to the black glazed porcelain from the Xiao kiln, and the chemical characteristics of the glaze are high Fe₂O₃ (5.14%) and CaO (7.26%) and low Al₂O₃ (11.85%) and the RO content is 0.83which is indicative of a calcium glaze and is close to the components of oil spot porcelains from Shanxi in northern China. The ferric oxide crystalline on the glaze surface indicates the phase transformation of γ-Fe₂O_3→ε-Fe₂O_3→α-Fe₂O₃ in the crystallization layer on the glaze surface and the anorthite crystalline at the junction between the body and the glaze. The vessel could be produced at a relatively high temperature in a specific oxidizing environment.     

湖田窑出土黑釉瓷的产地研究

景德镇湖田窑窑址的南宋、元地层出土了类吉州窑、类建窑以及自具特色的黑釉瓷片。本文通过研究它们胎釉的化学组成,并与吉州窑和建窑黑釉瓷的胎釉化学组成进行对应分析,认为湖田窑宋、元时期也生产自己的黑釉瓷。其南宋、元堆积层出土的黑釉瓷中有吉州窑和建窑的产品,为当时各窑烧制工艺相互交流的佐证。湖田窑生产的部分黑釉瓷模仿了吉州窑的选料标准,应该是学习吸收吉州窑烧造黑釉瓷工艺的结果,这类黑釉瓷可能是南宋时期生产的。而另一部分黑釉瓷使用了质量较差的瓷土作为制胎原料,可能是元代时生产的。     

景德镇明代仿天目瓷初考

研究了一片景德镇明朝成化时期仿天目瓷的样品,用显微镜进行观察,应用质子激发Ｘ荧光分析技术测定其主量,痕量化学组成,并与其它古代天目瓷加以比较。     

Angle dependence of Jian bowl color and its coloring mechanism

Jian bowl is generally known for its artistic appearance such as hare's fur and oil spots caused by the crystallization of iron oxides on the glaze surface. While very few Jian bowls have angle-dependent colors, scientific research on the topic is lacking owing to the scarcity of relevant samples. In this study, the angle-dependent colors of Jian bowls were systematically studied using various characterization techniques, such as angle-resolved reflectance spectra, X-ray diffraction, micro-Raman, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The angle dependence phenomenon of Jian bowl colors was classified into two types, and the coloring mechanisms were clarified. The first type of coloring mechanism is assumed to be coherent light scattering by an amorphous photonic structure formed during the firing process, which has weak angle dependence. The second type of coloring mechanism is thin-film interference, which has obvious angle dependence and is closely related to the corrosion process of Jian bowls in the burial environment.     

钧瓷的兴衰与发展

从大量的历史文献资料及古代钧窑遗址出土的许多钧瓷残片证明,我国宋代五大名瓷之一的钧窑源于唐代,研制于五代,成熟于北宋初期,兴盛于北宋中晚期。经历了由民窑到官窑,又民窑再官窑的发展阶段,开辟了我国陶瓷颜色釉的先河,为瓷器的装饰艺术提供了广阔的空间。     

Potential fingerprints for the usage of botanic ash in the glaze recipes of the Jizhou tea bowl

A glaze slip made from a mixture of porcelain clay and flux was melted at high temperatures to form an amorphous glaze layer on a ceramic body. All information about the raw materials and recipes of the glaze was lost in this process, leading to difficulties in the reconstruction of the ceramic-making process performed in ancient China. Herein, the refiring experiment was performed and the thermal dilatometer (DIL), X-ray diffractometer (XRD), X-ray fluorescence (XRF) and field emission scanning electron microscope (SEM) were utilized to investigate the crystallization behavior in the glazes of an underfired Jizhou tea bowl. The results showed that diopside, fluorapatite, and anorthite crystallized from the heterogeneous glaze slip, induced by the inhomogeneity of the raw materials and the incomplete mixing process, during the firing process in the glazes of the Jizhou tea bowl. All these crystals melted with increasing temperature, indicating the importance of the underfired samples in reconstructing the ancient ceramic-making technique. Diopside and fluorapatite could be potential fingerprints to identify the usage of botanic ash in the glaze recipes.     

Phase-separated Tenmoku “Blue” glaze: Microstructure and coloring mechanism

Yohen Tenmoku, a masterpiece of Jian kiln with bright blue rendering effect under different incident light, is lack research as only three intact pieces exist in the world. Herein, this study was fortunate to work with Jianxing Sun to conduct technical characterization and material analysis of the imitation Yohen Tenmoku (Song). Black oil spots are composed of magnetite (10–25 µm) and Al doping in hematite (1–3 µm) precipitated on the glaze surface. Brilliant blue color a combination of the bright blue structural color resulting from the coherent scattering of amorphous photonic crystals composed of spherical phase separation structures of 130 nm and the coloring of iron ions produced in a weak reducing atmosphere by the addition of high iron glazes with composite alkali (CaO and MgO). Continuous refraction and reflection of the structural color between the blue glass phases gives the glaze a shiny and dazzling blue color.     

Study on the coloring mechanism of the Ru celadon glaze in the Northern Song Dynasty

The Ru kiln is one of the five most famous kilns in the Chinese Song Dynasty. To clarify the coloring mechanism of the Ru celadon glaze, the celadon samples from the Ru Guan kiln site of Qingliangsi were analyzed by spectrophotometer, X-ray fluorescence spectrum, Raman spectroscopy, scanning electron microscopy and X-ray photoelectron spectrum. The results indicated that the molar ratios of SiO₂/Al₂O₃ and CaO/(CaO + Al₂O₃) affected the formation of micro-bubbles, anorthite crystals and phase separated structures. A large number of bubbles and anorthite crystals formed special glossiness and opacifying effect in the Ru celadon glaze. And then, dense phase separation droplets in the amorphous region were in short-range order, but their diameters (31–46 nm) were too small to form visible structural colors on glaze surfaces. Only “opal effect” was formed by the light scattering, which added the aesthetic feeling for the Ru celadon. Besides, the phase separation droplets intensified the segregation of iron, and thus deepened the chemical color and made the Ru celadon glaze appear green-blue. Due to the neutral to alkaline soil at the Ru Guan kiln site, the water in the soil and its corrosion on the Ru celadon glaze resulted in the formation of Si–OH bond.     

Colouring mechanism and firing process of celadon from the Xiangzhou kiln in Anyang,China, from the 5th-7th century

The Xiangzhou kiln was the largest celadon kiln site in northern China from the Northern and Southern Dynasties to the Sui Dynasty (5th-7th centuries). In order to investigate the colouring mechanisms and firing process of two types of celadon (yellow-green and earthen-yellow glazes) from the Xiangzhou kiln, samples were tested and analysed using OM, ED-XRF, TD, SEM-EDS, LRS, XPS and UV-Vis-NIR. The study results show that most of the samples in the two enamels have different formulations. The celadon glaze of the Xiangzhou kiln contains a small amount of quartz, anorthite and other crystals. The yellow-green glaze is fired in a reducing atmosphere and the earthy yellow glaze is fired in an oxidising atmosphere. The colouring mechanism of the Xiangzhou kiln celadon is mainly dominated by the chemical colouring of ionic colouring and aided by structural colouring caused by the microstructure (bubbles, various crystals, fractal structures, etc.).     

试论宋代吉州窑黑釉茶盏的装饰艺术

在宋代的瓷窑中,吉州窑以烧制黑釉茶盏而闻名于世,黑釉茶盏的大量烧制与宋代斗茶的兴起密切相关。黑釉茶盏的装饰丰富多彩,有各种窑变釉装饰、剪纸贴花装饰、木叶纹装饰等,极富地方特色与民俗风情。     

从化学组成上区分宋代汝瓷与民窑钧瓷

应用质子激发Ｘ荧光分析技术测定了一组宋代汝瓷和一组宋代民窑钧瓷瓷片的化学组成及浓度，对汝瓷与民窑钧瓷的主量，次量化学组成和痕量化学组成进行了比较，应用模式识别方法加以研究，得到了区分宋代汝瓷和民窑钧瓷的可视分类图和数学判据。     

Firing process and colouring mechanism of black glaze and brown glaze porcelains from the Yuan and Ming dynasties from the Qingliang Temple kiln in Baofeng,Henan, China

Black glaze and brown glaze porcelains were an important part of ancient Chinese iron-based high temperature glazes. The excavation of black glaze and brown glaze porcelains from the Yuan and Ming dynasties at the Qingliang Temple kiln site in Baofeng, Henan, China, in 2014, enriched the firing history of this kiln site and history of Chinese ceramics. In this study, black glaze and brown glaze porcelain samples from the Qingliang Temple kiln site from the Yuan and Ming dynasties were selected and analysed via optical microscopy, laser Raman spectroscopy, focused ion beam scanning electron microscopy combined with EDS and energy dispersive X-ray fluorescence to determine their microscopic morphology, microzone composition, microstructure and chemical composition. Moreover, the main wavelength range of the brown glaze porcelain samples were measured by UV–Vis–NIR spectrophotometer systems. The main conclusions of this study are as follows. The brown glaze porcelain from the Yuan and Ming dynasties at the Qingliang Temple kiln site has two different colour layers, with the surface is brown and the bottom is black. The presence of a glass phase and α-Fe₂O₃ phase in the black glaze porcelain samples, and a rare ε-Fe₂O₃ phase in the brown glaze porcelain samples. The brown colour was a result of ε-Fe₂O₃ precipitation, whilst the black base layer also enhanced the brown-colouring effect. Different glaze formulations were used for brown glazed porcelain, some of which were similar to those used for black glaze porcelain and derived from the transformation of black glaze porcelain through different firing atmospheres and cooling rates. Although the formula of the brown glaze porcelain samples exhibited differences, the main wavelength difference was not large, was within the 645–682 nm range and belonged to the visible red region.     

寿州窑瓷器造型文化研究

江淮名窑寿州窑,创烧于我国南北朝时期,兴盛于隋唐,衰落于五代宋。在其悠长的发展历程里,寿州窑烧制了许许多多的陶瓷用品,大致可分为饮食器、盛储器、酒具、文具、寝具、玩具、建筑用瓷等,釉色崇尚黄、黑釉,造型浑厚饱满,古朴沉稳,姿态万千,多样的的造型符号传递了当时的社会文化背景、瓷器制作水平和审美文化,为深入研究中国古陶瓷文化提供了珍贵的资料,对当今的文创产品开发也大有裨益。     

Study on the phase-separated opaque glaze in ancient China from Qionglai kiln

Qionglai kiln is a famous folk kiln site in China. Six pieces of opaque green-glazed porcelain shards with mild gloss and jade-like feel fired in the Tang dynasty (618–907 A.D.), were adopted as test samples. The correlation among composition, microstructure, firing technique and glaze appearance has been investigated by means of energy-dispersive X-ray fluorescence, field emission electron microscopy, direct transmission electron microscopy, X-ray diffraction and refiring experiment. The study has demonstrated that the opaque green glazes from Qionglai kiln site are high-temperature calcia–magnesia–silicate glazes and typical of phase-separated glazes. The liquid–liquid immiscibility structure plays a key role for the artistic appearance of the glazes.     

Effect of phase separation on the Jian ware blue colored glaze with iron oxide

This study was aimed to explore the effect of phase separation on the Jian ware blue colored glaze with iron oxide. In order to analyze the forming cause of glaze patterns and their coloring mechanism, the phase, microstructure and chemical state of the samples were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectrum. The results indicated that the addition of calcium phosphate introduced highly-active Ca²⁺ and P⁵⁺ into the glaze. Since Ca²⁺ with high ionic potential had a greater ability to appeal O^2? than Si⁴⁺, the glaze melt was separated into calcium-rich phase and silicon-rich phase. The difference of viscosity caused the non-uniform distribution of quartz and glass phase, and then affected the distribution of iron ions in two phases, which formed glaze patterns. Adding P⁵⁺ that had a strong effect of reversed polarization on the Fe-O increased the contents of Fe²⁺ and Fe³⁺-O-Fe²⁺, and thus deepened the blue-green of glaze surface. In addition, it promoted the formation of worm-like phase-separated structures and the existence of structural color. Therefore, phase separation enriched not only patterns but also glaze colors of the Jian ware blue colored glaze.