Fig. 1. (a) Fe-Al binary phase diagram [29]; (b) Variation of △Gθ of Fe-Al IMCs with different temperatures [10].

Fig. 2. (a) Cross-sectional SEM image of as-coated steel; (b) magnified micrograph of dotted rectangular region in (a), adapted from Ref [28].

Fig. 3. Existence forms of FeAl3 after immersion in liquid aluminum [24].

Fig. 4. Schematic of the formation of hot dip aluminized coating layer on steel [36].

Fig. 5. Schematic formation of three-layer structures with Al coating on steel [42].

Fig. 6. Schematic diagram on growth of Fe-Al interfacial layer.

Fig. 7. Dependence of Fe2Al5 thickness on time: (a) average thickness of Fe2Al5 and (b) maximum thickness of Fe2Al5 [24].

Fig. 8. (a) Variation of the FeAl3 layer thickness with time at 800 ℃, adapted from Ref. [17]; (b) variation of the FeAl3 layer average thickness with t1/2 at 800 ℃, adapted from Ref [18].

Fig. 9. Schematic of the interfacial reaction between ferrous alloy and Al melts [10]: (a) t = 0, ferrous alloy and Al melts just contacted with each other; (b) t = t1 (t1 > 0), at interface I, ferrous alloy has reacted with Al atoms diffusing through the layer to form FeaAlb; at interface II, FeaAlb has dissolved into the Al melts.

Fig. 10. Matrix thickness loss of ferrous alloys vs. corrosion time [10].

Fig. 11. Microstructure of the interface of hot-dip-aluminized carbon steel, adapted from Ref [7].

Fig. 12. SEM images of the cast iron immersed in the aluminum melts at 750 ℃ for 24 h, adapted from Ref. [10]: (a) flake graphite in HT150; (b) spheroidal graphite in QT500; (c) black precipitates of Al4C3.

Fig. 13. SEM micrographs of FeCrB alloys [77].

Fig. 14. Cross-sectional interfacial morphology of Fe-Cr-B cast steel immersed in molten aluminum for 8 h [81].

Fig. 15. (a) SEM image of corrosion interface formed in the novel ferrous alloy after 0.5 h in the dynamic Al melts at 750 ℃ [84]; (b) carbides and nano-ceramic particles dispersed in the matrix.

Fig. 16. Schematic of the erosion-corrosion mechanisms of novel FeCrB alloys in Al melts [84].

Fig. 17. Schematic diagram of corrosion along the grain boundary by molten Al [44].