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.     

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.