Efflorescence on excavated pottery from the Han tomb in Dongnan Town, Shaanxi, China

Abstract

This poster presents the typical salt efflorescence on the glazed and grey pottery (Fig. 1) excavated from the Han tomb in the Banqiao Ditch and Hegou Erdui in Dongnan Town, Baoji, Shaanxi, China. The composition, crystalline structure, firing temperature, physical properties, micromorphology, and salt content in these pottery types, with and without salt efflorescence, were compared to investigate the interaction between the clay bodies and their glazing. Environmental conditions such as temperature, relative humidity, and hydrogeological conditions at the excavation site were analysed by a multivariate statistical method . It was found that 2‒5% soluble salts contained in the potteries such as Cl, NO3 , Na, and Ca were the main components of the efflorescence. The source of these soluble salts was mainly from the hydrogeological burial environment. Study of the phase equilibrium of the soluble salts Cl, NO3 , Na, and Ca and the kinetics of crystallisation of soluble salts interaction with laser diffractometry, scanning electron microscopy, atomic force microscopy, and thermal gravimetric analysis allowed the effect of soluble salts on the efflorescence from different pottery bodies to be studied quantitatively on the microscopic scale. The crystallisation stress and the expansion coefficient between the glaze and the pottery body caused by soluble salts were studied. The interaction between the soluble 本文以陝西寶雞東南鎮板橋溝和河溝二隊漢墓出土