<p>NiAl coatings were applied to the surfaces of FeCoNi superalloy and stainless steel substrates using atmospheric plasma spraying (APS) technology. The corrosion characteristics of the thermally sprayed NiAl coatings were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical tests, including open-circuit potential measurements, potentiodynamic polarization curves, and galvanic corrosion experiments. The galvanic corrosion behavior of the NiAl coatings when paired with FeCoNi superalloy and stainless steel substrates was also investigated. The results indicated that the NiAl coatings exhibited a porous, continuous microstructure, with aluminum oxidation during spraying forming Al₂O₂. Potentiodynamic polarization tests revealed that the NiAl–stainless steel system had a relatively lower corrosion potential. Furthermore, galvanic corrosion experiments demonstrated that the average galvanic current density of the NiAl–FeCoNi couple (21 μA/cm2) was lower than that of the NiAl–stainless steel couple (26 μA/cm2). A four-level Daubechies wavelet transform (db4) analysis of the galvanic current signals showed that the D-series crystal energy of the NiAl–FeCoNi couple was lower, indicating weaker electrochemical reactivity. The corrosion evolution of the NiAl coatings was significantly influenced by their porous structure and the dynamic dissolution behavior of the surface oxide film. The NiAl–FeCoNi galvanic system exhibited superior resistance to galvanic corrosion due to its lower electrochemical activity.</p>