Proto-porcelain, a kind of high-fired lime-rich glazed ceramic, with maturing temperatures in excess of 1200 °C, began to appear in China during the Shang dynasty (c. 1700 to 1027 BC) and became more widespread during the subsequent Zhou dynasty (1027 to 221 BC). Since the 1950s, proto-porcelain has been unearthed from various tombs and sites across the country; most of them in mound tombs and kiln sites in the lower reaches of the Yangtze River. Bodies and glazes of 61 proto-porcelain sherds and 19 non proto-porcelain samples from Shang and Zhou periods production sites in Deqing, Zhejiang province were collected and later analysed by EPMA-WDS to understand the raw materials and to explore the mechanisms behind the formation of these glazes. The results indicate that the bodies of all samples were made from local raw material – porcelain stone. Wood ashes, high in lime and low in potash, were intentionally applied to the proto-porcelain samples, resulting in the formation of lime-rich glazes whose composition were determined by a temperature-controlled mechanism. In contrast, kiln fragments and furniture show a potash-rich fuel vapour glaze, which formed unintentionally during use of the kiln. The firing temperature for most of the proto-porcelain glazes is about the same as the maturing temperature for typical more recent lime glazes, showing that the potters were already at such an early time able to attain sufficiently high temperature in their kilns. The differences in firing temperature and composition underpin the suggestion that the Chinese lime-rich glazes are an independent invention. The glaze-forming process was later replicated in the lab to further test several possible parameters that would be necessary to control for the early potters when producing these glazes on a regular scale. The emergence of these earliest high-fired glazed ceramics has also been contextualised within north and south China during the Shang and Zhou dynasties. The environmental and technological constraints, economic and political organisations, together with religious and belief systems were also taken into consideration to better understand the impact of this innovation of the glazing and firing technology on the later development of Chinese ceramic production.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:625971 |
| Date | January 2012 |
| Creators | Yin, M. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1380281/ |
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