Plasma nitriding is a widely used technology to enhance the surface performance and extend the service life of alloy parts.The current research mainly focuses on the influences of time,temperature,gas type and pressure parameters on nitriding behavior,while fewer studies have been conducted on the electric potential.This paper mainly reports the effect of the electric potential on nitriding behavior.Test conditions were set using cathodic,anodic and floating potentials in a plasma nitriding furnace.2Cr13 stainless steel was nitrided at 450 ℃ for 5 h in an NH3 atmosphere.The experimental results show that the nitriding treatment can be well performed under the different electric potentials,but differences exist in microstructures,morphologies and performance results of the modified layers.The thickness and hardness values of the nitrided layer are ranked as follows:cathodic ＞ anodic ＞ floating potential.The anodic nitrided surface has an obvious particle deposition layer composed of nitrides and oxides.Electrochemical and tribological experiments show that the corrosion resistance and wear resistance were significantly improved after a nitriding treatment using the three electric potentials.Moreover,the floating nitriding treatment resulted in the best tribological performance and corrosion resistance.