AN INVESTIGATION INTO THE RELATIONSHIP BETWEEN THE RAW MATERIALS USED IN THE PRODUCTION OF CHINESE PORCELAIN AND STONEWARE BODIES AND THE RESULTING MICROSTRUCTURES

摘要

The microstructures of porcelain and stoneware bodies from north and south China, spanning the period fromthe Tang to the Ming dynasty (7th–17th centuries AD), were examined in polished sections in a scanning electron microscope (SEM) after etching the sections with hydrofluoric acid (HF). Mullite, present as fine, mainly elongated crystals, is the dominant crystalline phase observed. The bulk chemical compositions of the bodies are determined by energy-dispersive spectrometry in the SEM, and the relative amounts of mullite and quartz present in the different ceramics are estimated from X-ray diffraction measurements. Mullite formed from areas of kaolinitic clay, mica particles and feldspar particles is distinguished through a combination of the arrangement of the mullite crystals, and the associated SiO_2/Al_2O_3 wt% concentration ratios. It is shown that very different microstructures are observed in ceramic bodies produced using kaolinitic clay from north China (Ding porcelain and Jun stoneware), porcelain stone from south China (qingbai and underglaze blue porcelain and Longquan stoneware), and stoneware clays from south China (Yue and Guan stonewares). Therefore, SEM examination of HF-etched, polished sections of the bodies of high-refractory ceramics has considerable potential for investigating the raw materials used in their production.