Studies on the Thermal Properties of Japanese Old Potteries (I)

In these studies, about twenty samples of Japanese old potteries of various ages, such as Jomon, Yayoi and Sueki, were physically and chemically investigated. The results of studies are summarized as follows (1) The chemical compositions except water contents can not be characteristic of the ages. (2) The potteries of the Jomon and Yayoi ages contain clay minerals which remain under low temperature, while those of the Sueki have mullite and crystobalite which occur at high temperature. (3) The differential thermal analysis shows that thepotteries of the Jomon and Yayoi ages were produced under low temperature and those of the Sueki were produced under comparatively high temperature. (4) The thermobalance indicates the considerable loss of quantity of the potteries of the Jomon and Yayoi ages between 100゜C and 300゜C. Thepotteries of the Sueki did not degrade their weights by heating until 1100゜C. (5) On the basis of the above-mentioned results, the writer considers that the potteries of the Jomon and Yayoi were fired between 600゜C and 700゜C, and those of the Sueki were heated between 900゜C and 1100゜C