Pitting and galvanic corrosion behavior of stainless steel with weld in wet-dry environment containing Cl^-

Cui Lin1,2), Xiaogang Li2,3), and Chaofang Dong2) 1) School of Material Science and Technology, Nanchang Hangkong University, Nanchang 330063, China 2) Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China 3) State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China

摘 要：Accelerated corrosion test of stainless steel with weld was carried out to investigate the corrosion behavior under the wet-dry cyclic condition in the atmosphere containing Cl?. In the surface morphology, corrosion products were analyzed by metal- lographic observation, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the damage to stainless steel with weld in the atmosphere containing Cl? is due to localized corrosion, especially pitting and galvanic corrosion. Weld acts as the anode, whereas matrix acts as the cathode in the corrosion process. The pitting corrosion, including the nucleation and growth of a stable pit, is promoted by the presence of wet-dry cycles, especially during the drying stage. Pits centralizing in weld are found to be grouped together like colonies, with a number of smaller pits surrounding a larger pit. The composition of the corro- sion products is Fe2O3, Cr2O3, Fe3O4, NiCrO4, etc.

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