Abstract: The conventional and nanometer-sized powders prepared by powder metallurgy (PM) and mechanical alloying (MA) were pressed into PM, MA Co-20Fe-20Cr and PM, MA Co-20Fe-30Cr bulk alloys using vacuum hot-pressing technology. The corrosion behavior of these alloys in 0.5 mol/L NaCl solution and the influence of nano crystallization and Cr content were investigated by electrochemical testing technology. The results show that under the experimental conditions, the corrosion current densities of the two nanometer alloys decreased by 5.066 9 μA/cm² and 1.670 3 μA/cm², and the charge transfer resistances increased by 29 675 Ω/cm² and 30 947 Ω/cm², respectively, compared with their conventional-sized counterparts. Nano crystallization can improve the corrosion properties of the alloys. Moreover, the corrosion current densities of the two Co-20Fe-30Cr alloys decreased by 3.5811 μA/cm² and 0.184 5 μA/cm², and the charge transfer resistances increased by 10 633 Ω/cm² and 11 905 Ω/cm², respectively, compared with those of the corresponding Co-20Fe-20Cr alloys. A 10% increase in Cr content improves corrosion performance.