Fig. 5: Characterization of Type I slags after corrosion testing.

a–e Slice and view scanning electron microscopy (SEM) images after successive plasma focus ion beam milling of a pitted Type I slag. All insets are higher magnification images of the regions marked with red circles. Each inset highlights specific feature: b A discontinuity of the slag where the NaCl solution was able to penetrate the metal, c Solidification cells after metal dissolution, d The edge of the lag that delaminated. e A metal inclusion in the slag that dissolved due to the solution. f Scanning transmission electron microscopy (STEM) high angle annular dark field and g STEM energy dispersive X-ray spectroscopy maps of a crack tip in a corroded Type I slag that did not pit.