Compositional and structural characterization of npFe⁰ regions in SSW rims. (a) HAADF image of the 5 hr sample. (b) Fe concentration map (see Section 2.2.3) of the 5 hr sample in the same region as (a). (c) Fe/Ti ratio map (see Section 2.2.3) of the 5 hr sample in the same region as (a). (d)–(f) Same as (c), but for the 12 hr sample. (g) High-resolution HAADF image of npFe⁰ in the 5 hr sample with d-spacing corresponding to the {110} family of planes in α-Fe. Inset: fast Fourier transform of the crystalline npFe⁰ region.