Fig. 7.

a BSE overview image, b, c Na-distribution maps of long (left) and short (right) crack, d), e K-distribution maps of long (left) and short (right) crack, f, g contour maps for K-mole fraction; the irregularly shaped thin lines are the contours obtained from quantitative element maps, the heavy solid lines are calculated from a 2D diffusion model; the data are from the 12 day experiment