<p>The corrosion behaviors of FeCoCrNiMn-(N,Si) and FeCoCrNiMn high-entropy alloys (HEAs) in 0.5&#xa0;M H₂SO₄ aqueous solution were investigated. Electrochemical measurements showed that FeCoCrNiMn-(N, Si) has a more negative initial passivation potential and a lower initial passivation current density compared to FeCoCrNiMn, which was related to the denser passive film with lower carrier concentration that formed on the surface of the FeCoCrNiMn-(N,Si). Corrosion pits on FeCoCrNiMn-(N,Si) were also fewer and smaller. Thus, FeCoCrNiMn-(N,Si) showed superior corrosion resistance to FeCoCrNiMn, which can be ascribed to the enrichment of N and Si in the form of NH₄⁺ and SiO₂ on the surface of the passive film, as well as the presence of Cr₂O₃. The enhanced corrosion resistance in H₂SO₄ solution of FeCoCrNiMn by N and Si alloying is due to the formation of SiO₂ with good corrosion resistance; the formation of NH₃, which contributes to the consumption of H⁺ that is beneficial for the nucleation and growth of passive films; and the improved protection performance of passive film by Cr₂O₃ transformed from Cr₂N.</p>