采用等离子体源渗氮技术在304L奥氏体不锈钢表面制备高氮面心结构的γ_N相层，利用阳极极化曲线和电化学阻抗谱（EIS）研究γ_N相在pH=8.4硼酸缓冲溶液中的腐蚀行为。结果表明：γ_N相的阳极极化曲线呈现出自钝化-过钝化溶解过程，自腐蚀电位E_corr较原始不锈钢提高了75 mV，维钝电流密度J_p降低近一个数量级，耐蚀性能明显提高。与原始不锈钢钝化膜相比，γ_N相钝化膜的EIS容抗弧直径及|Z|值增大，相位角平台变宽，其电荷转移电阻R_ct增至1.064×10⁷ Ω·cm²，双电层电容C_dl降至65.4 μF/cm²，说明γ_N相钝化膜更致密，表现为近电容特性。随着浸泡时间增加，γ_N相钝化膜的R_ct稳定在10⁷ Ω·cm²量级，具有良好的稳定性。

A single high-nitrogen face-centered-cubic phase (γ_N) layer formed on the plasma source nitrided AISI 316 austenitic stainless steel. The electrochemical corrosion behavior of the γ_N phase in boric acid buffer solution with a pH 8.4 was studied by anodic polarization and electrochemical impedance spectroscopy (EIS). The results show that the anodic polarization curve of the γ_N phase presented a typical transition course from spontaneous passivation into passivation-transpassive dissolution process. Compared with the original stainless steel, the E_corr of the γ_N phase layer increased 75 mV, the passivation current density deduced one order magnitude. The EIS of the γ_N phase passive film had a larger diameter of capacitive arc, higher impedance modulus|Z|, and wider phase degree range, compares with the original stainless steel film. Correspondently, the interfacial charge transfer resistance R_ct of the γ_N phase passive film increased to 1.064×10⁷ Ω·cm² and calculated double layer capacitance C_dl decreased to 65.4 μF/cm². With the immersion time increased, the interfacial charge transfer resistance R_ct of the γ_N phase passive film was stable to a magnitude of 10⁷ Ω·cm². The high insulation of the γ_N phase passive film with higher compactness led to an improved corrosion resistance of the original stainless steel.