Effects of salts and its mixing ratio on the corrosion behavior of 316 stainless steel exposed to a simulated salt-lake atmospheric environment

The effect of mixed salts and mixing ratio on the corrosion behavior of 316 stainless steel exposed to a simulated salt-lake atmosphere has been firstly investigated. 316 stainless steel was mainly analyzed by the evolution of surface morphologies, composition of corrosion products, statistics of pits depth and width and electrochemical measurements. The results indicated a layered double hydroxides (LDH) was detected in the corrosion products formed on 316 stainless steel surface under different salt deposition conditions, except under single NaCl deposition condition. When the mole fraction of NaCl was 0.75 in mixed MgCl2 - NaCl salts, the corrosion rate of 316 stainless steel was the fastest. The width of the pits formed on the surface of 316 stainless steel under mixed MgCl2 - NaCl salts deposition conditions was smaller than that under single MgCl2 deposition condition. The differences in corrosion rate and pit width size of 316 stainless steel under mixed MgCl2 - NaCl salts deposition conditions and single MgCl2 deposition condition were related to diffusion barrier provided by the neighboring NaCl crystals precipitated in thin liquid film during the humidification process and dehydration process.