備前焼表面の“火襷”の発色に及ぼすヘマタイトの影響

抄録

The formation of Hidasuki, a characteristic red-colored pattern on the surface of Bizen-yaki, was investigated from the viewpoints of its mineral composition and coloration. Hematite, corundum and quartz were found in Hidasuki. Corundum was formed regardless of the cooling rate after heat treatment of a mixture of Bizen-clay and 8 to 10wt% potassium chloride at 1300°C for 3h. Hematite was not formed when the mixture was quenched. However, the amount of hexagonal plate like hematite in the heated mixture increased with the lowering of the cooling rate, and the color of the heated mixture became more reddish with the increase of the amount of hematite. The same phase composition, coloration and morphology as those of Hidasuki were obtained when a mixture of Bizen-clay and 8 to 10wt% potassium chloride was heated at 1300°C for 3h followed by cooling at the rate of 0.2 to 0.5°C/min in air.