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Effects of Rice Straw on the Color and Microstructure of Bizen, a Traditional Japanese Stoneware, as a Function of Oxygen Partial Pressure
Author(s) -
Kusano Yoshihiro,
Doi Akira,
Fukuhara Minoru,
Nakanishi Makoto,
Fujii Tatsuo,
Takada Jun,
Ikeda Yasunori,
Takano Mikio,
Henrist Catherine,
Cloots Rudi,
Rulmont André,
Ausloos Marcel
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.03125.x
Subject(s) - pellet , microstructure , pellets , oxygen , hematite , partial pressure , materials science , chemistry , rice straw , nitrogen , metallurgy , mineralogy , straw , composite material , inorganic chemistry , organic chemistry
The effects of oxygen partial pressure during thermal treatment on the color and microstructure of Bizen, a traditional Japanese stoneware, were studied through model experiments using clay pellets covered lightly with rice straw as a coloring assistant. When heated in flowing nitrogen, the model pellet turned blackish owing to the formation of α‐Fe particles coated with graphite. However, schreibersite (Fe 3 P), which is also blackish, was formed specifically on the pellet surface in direct contact with the straw. The rice straw seems to have generated a strongly reducing atmosphere, strong enough for the metallization to α‐Fe, and also to have provided phosphorus through contact. When oxygen content in the surrounding gas atmosphere was raised to N 2 /O 2 =99/1, the pellet surface turned yellowish brown because the main coloring material was Fe 3+ ‐containing mullite. At oxygen contents of N 2 /O 2 =98/2 or more, the formation of hematite (α‐Fe 2 O 3 ) pushed the color to deep red.