Fig. 10: SEM images of corrosion features in bubbles.

a Open indentation formed by the connection of several circular pits. The area in the box shows multiple micro-cracks on the inner walls of the pits (Supplementary Fig. 3); b A pore on the bottom surface; c Box 1 shows a severely corroded annular pit; Box 2 shows the area where the residual glaze in the annular pit is partially connected to the surrounding glaze surface; d Cross section of an annular pit.