从工艺技术论越窑青釉瓷兴衰

DISCUSSION ON RISE AND DECLINE FOR YUE GREEN WARE FROM TECHNOLOGY

考古学家一般认为东汉至两晋为越窑的创始和发展时期 ,唐至北宋为鼎盛时期 ,南宋后即停烧。其产品风格虽因时而异 ,但还是一脉相承。可见越窑青釉瓷在长达近千年的烧制过程中历经创始、发展、鼎盛和衰落的全过程。越窑青釉瓷的兴衰固然和当时的政治、经济及其它因素有关 ,但它的工艺技术也应在它的兴衰全过程中起着非常重要的作用。本文即是在对各地历代越窑出土的瓷片科学技术研究的基础上 ,从它的工艺技术角度讨论它的兴衰。越窑青釉瓷所用的原料始终没有多大变化 ,其中Fe2 O3和TiO2 的含量都比较高 ,致使胎呈不同程度的灰白色 ,釉呈青中带黄或灰的色调。更由于釉中含有较高的CaO ,较低的K2 O和Na2 O ,遂使它只能是薄层的玻璃釉 ,无法取得莹润如玉的效果。越窑青釉瓷的烧成温度则变化较大 ,低者只有 10 5 0℃ ,而高者可达 13 10℃。在刚兴起的东汉由于所用龙窑较小 ,其长度只有10m左右 ,其烧成温度可达 13 0 0℃ ,而到了宋代 ,由于龙窑的长度已增加到 5 0m左右 ,致使他的烧成温度只保持在 110 0℃左右。这样的烧成温度对越窑青釉瓷产生了不利的影响。

It is generally believed that the production of Yue ware began and developed in the Eastern Han and the Two Jin Dynasties,flourished in the Tang Dynasty and the Northern Song Dynasty,stopped after the Southern Song Dynasty.Its sytles of products were different in different times,but they could be traced to the same origin.It is obvious that Yue ware went through its beginning,development,flourish and decline in one thousand years production history. Although the rise and decline of Yue ware production was related to politics,economy and other factors at that time,its technology should play a very important role in the process of the rise and decline.According to the research on the sherds excavated in various production places of Yue ware in successive dynasties,its rise and decline were discussed from its scientific and technological viewpoint in this paper. There didn't exist great change in raw material for Yue ware throughout its production process.The contents of Fe 2O 3 and TiO 2 were highter.As a result bodies presented grayish white to varying degrees and glazes presented green with yellow or gray tinct.Furthermore the content of CaO was higher and those of K 2O and Na 2O were lower,there only existed thin glass glaze.Such glaze could not have jade-like appearance effect. The firing temperatures of Yue ware varied from the low temperature 1050℃ to the high temperature 1310℃.In the Eastern Han Dynasty the newly-originated dragon kilns were small.They were only about 10 meters long.The firing temperatures could be as high as 1300℃.But in the Song Dynasty the length of the dragon kilns were raised to 50 meters or so.Its firing temperature could only maintain 1100℃.Such firing temperature exerted an unfavorable influence on Yue ware. The chemical compositions for the bodies and glazes of Yue ware and its firing process as well as the rise of other famous wares in the Song Dynasty played very important role in whole process of the rise and decline of Yue ware.