利用腐蚀挂片试验与循环极化测试的方法，结合光学显微镜、扫描电子显微镜（SEM）、能谱仪（EDS）等测试手段研究了2205双相不锈钢在南海水下170 m海水中的腐蚀行为。结果表明：2205双相不锈钢在深海环境中发生了局部腐蚀；浸泡初期，不锈钢表面形成微生物保护膜，在微生物膜的保护下其耐蚀性能提高；随着浸泡时间的延长，微生物死亡、脱落，失去对金属基体的保护作用，导致不锈钢耐蚀性能下降；同时，残留的微生物膜与不锈钢基体间形成缝隙，在溶解氧与Cl^-作用下发生缝隙腐蚀，形成局部腐蚀坑。

The corrosion behavior of 2205 duplex stainless steel in the seawater under 170 m of South China Sea was studied by coupon corrosion testing and cyclic polarization testing in combination with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that localized corrosion occurred on the 2205 duplex stainless steel in deep-sea environment. At the initial stage of immersion, a microbial protective film was formed on the surface of the 2205 duplex stainless steel, and the corrosion resistance of the stainless steel improved under the protection of the microbial film. As the immersing time increased, microorganisms died and sloughed off, and then lost the protection for metal substrate, resulting in the decrease of corrosion resistance of the 2205 duplex stainless steel. A gap was formed between the residual microbial film and the stainless steel substrate, and crevice corrosion occurred under the action of dissolved oxygen and Cl^- to form localized corrosion pits.