<p>This study investigated the high-temperature oxidation resistance of various nickel-based coatings applied to several common boiler steels (T22, SA516, T11, T91, and Gr A1). The research utilized a wire arc spray technique to apply three distinct coating compositions: Ni-20Cr, Ni-5Al, and Ni-Cr-Ti. The primary objective was to evaluate how these coatings, as well as the bare steels, perform under cyclic air oxidation at 900&#xa0;°C for 50 cycles. Before the oxidation tests, the coatings were thoroughly characterized for their microstructure, elemental composition, porosity, and hardness. The results demonstrated that all three coatings significantly improved the oxidation resistance of the steels compared to their uncoated counterparts. The Ni-20Cr coating proved to be the most effective, particularly on SA516 and Gr A1 steels, where it yielded the lowest parabolic rate constant (Kp) and minimal weight gain. Specifically, on SA516 steel, the Kp was reduced drastically from 3107 × 10⁻¹⁰&#xa0;g²/cm⁴/s to a mere 4.5 × 10⁻¹⁰&#xa0;g²/cm⁴/s.</p><p>However, the performance varied with the substrate. The Ni-5Al and Ni-Cr-Ti coatings showed promising results on T91 steel but exhibited cracking and spallation on the T22 substrate, highlighting the critical role of substrate–coating interactions. The study’s novelty lies in its comprehensive, direct comparison of multiple coating compositions on a wide range of commercially relevant steels under identical test conditions. This approach provides a unique and valuable dataset for guiding material selection in high-temperature boiler environments, where such detailed comparative information has been previously unavailable. The findings offer crucial insights into optimizing protective coatings for demanding industrial applications.</p>