Fig. 7

OM and SEM images of sample No. 09, a and b polished cross-section; c–e a corroded region at different magnification, located near a crack at the glaze-body interface in (b), where P1, P2 and P3 in (d) are phase-separation region, short column-like anorthite crystals, and phosphorus-containing crystals, respectively; f the rectangle region in (e): the porous structure formed after the corrosion of glass phase; g and h a corroded area near a crack, where area A is the corroded area presenting as yellow, and area B shows the Mg-rich substances in the pores; i the rectangle region in (a), and the dashed arrow indicates the corrosion path in the glaze layer. f is a secondary electron SEM image and the others are backscattered electron SEM images. The marked positions (P1–P4) were examined by EDS and the results were listed in Table 6