Figure 14 illustrates the XPS analysis of the cation fraction of the as-cast, as-built, and ABH-973-48 samples during passivation. The corrosion properties of alloys are not significantly affected by passive film constituents, as the composition of the passive film did not significantly influence the surface of both the as-cast and as-built samples. It is well known that composition and microstructure differences are primary factors affecting their corrosion performance (Fig. 3a and Fig. 5a). Moreover, grain size has also been found to influence corrosion properties, as depicted in Fig. 5g. The as-built sample contains more metallurgical defects such as gas pores and cracks, making it more susceptible to localized corrosion because corrosion ions accumulate at defect sites, leading to severe corrosion. Conversely, the uniformly dispersed composition in the as-cast sample initiates low-grade grain-boundary corrosion more rapidly, as illustrated in Fig. 3a. High content of Cr, Al, and O in Fig. 14 indicates that prolonged annealing treatment has improved the alloy’s corrosion properties. This improvement further facilitated formation of a passive film composed of Cr2O3 and Al2O3, resulting in enhanced corrosion resistance.
