宋元时期天蓝钧釉分相呈色机理的实验考古研究

Experimental Archaeological Study on Phase Separation and Coloring Mechanism of Sky Blue Jun Porcelain Glaze during the Song and Yuan Dynasties

使用实验考古的方法,以长石、石英、高岭土、方解石、滑石、骨灰、氧化铁等原料对宋元时期钧瓷天蓝釉进行工艺再现,并利用超景深显微镜、透射电子显微镜、扫描电子显微镜与色度仪对烧制样品进行综合分析,探讨配方SiO_(2)/Al_(2)O_(3)摩尔比与骨灰含量对钧釉面外观及显微结构造成的影响,以进一步明晰宋元钧釉的分相和呈色机理。结果表明,配方中不含骨灰且Fe_(2)O_(3)含量不变时,随着SiO_(2)/Al_(2)O_(3)摩尔比的升高,釉中逐渐形成分布密集的微小分相,造成较强漫散射,釉色由透明青绿向乳白色转变,但不会形成天蓝色,因而SiO_(2)/Al_(2)O_(3)摩尔比是形成钧釉乳白色的主要原因;随着骨灰含量逐渐升高,釉中微小分相逐渐长大成球形与连通蠕虫形,尺寸60 nm~140 nm,增强了结构色,釉色由青绿向天蓝色转变,与宋元天蓝色钧釉相近,因而骨灰是形成钧釉天蓝色的主要原因。

Experimental archaeological methods are used to reproduce the process of Jun porcelain sky blue glaze in the Song and Yuan dynasties with feldspar,quartz,kaolin,calcite,talc,bone ash,iron oxide and other raw materials,including ultra depth of field microscope,transmission electron microscope,scanning electron microscope and colorimeter,in order to comprehensively analyze the fired samples.The effects of SiO_(2)/Al_(2)O_(3) molar ratio and bone ashes content on appearance and microstructure of Jun porcelain glaze were explored,so as to further clarify the phase separation and color formation mechanism during the Song and Yuan dynasties.When bone ashes are absent and the Fe_(2)O_(3) content is constant,as the molar ratio of SiO_(2)/Al_(2)O_(3) gradually is increased,a densely distributed silicon rich micro phases was formed in the glaze,resulting in strong diffuse scattering.The glaze color was changed from transparent green to milky white,but sky blue is not formed.Therefore,the SiO_(2)/Al_(2)O_(3) molar ratio was the main reason for the formation of milky white Jun glaze.As the content of bone ashes is gradually increased,the tiny particles in the glaze gradually grow into spherical and connected worm type ones,with sizes of 60–140 nm,enhancing the structural color.The glaze color varied from green to sky blue,similar to the Song and Yuan Dynasty sky blue Jun porcelain glaze.Therefore,the presence of bone ashes is the main reason for the formation of Jun glaze sky blue.