Figure 5

Coherent/incoherent Fe₂Ni₂N/FeNiN phase interfaces with ledgewise growth features. (a–c) ABF-STEM images and (d–f) the corresponding combined (Fe, Ni, and N) elements distribution mapping of the nitrided FeNi NPs. (g–i) High-resolution ABF-STEM images focusing on the detailed microstructure of the FeNiN/Fe₂Ni₂N interfaces. The observed areas are indicated by the dashed squares marked in the corresponding element distribution maps (d–f). The high-index/irrational OR developed at the FeNiN/Fe₂Ni₂N coherent (h)/incoherent (g,i) interfaces were indicated by the dashed line and one representative high-index orientation relationship present in (i) is schematised in (j). (k,l) ABF-STEM images of nitrided FeNi NPs with terraces/ledges demonstrating the ledgewise growth motion of the FeNiN/Fe₂Ni₂N phase interface in (a) and (c), respectively.