Corrosion Resistance and Electrochemical Corrosion Characteristics of Stainless Steel for Seawater Desalination Evaporator

Abstract

In order to explore the corrosion resistance of super stainless steels used in low temperature multiple seawater desalination device, S32205 duplex stainless steel and the super duplex stainless steel S32750 were tested by salt spray, alternate-immersion and full immersion tests and were studied by weight loss method. Electrochemical parameters characterizing corrosion resistance of stainless steel were obtained by measuring the potentiodynamic polarization and electrochemical impedance of the stainless steel. The results show that two kinds of stainless steels perform good corrosion resistance, the super duplex stainless steel S32750 has less pitting trace than S32205 duplex stainless steel. With the increase of temperature and concentration, the results the pitting potential decreases, the passivation current density and pitting sensitivity increases. The electrochemical impedance decreases with the increase of temperature and concentration. Compared with S32205 duplex stainless steel, the super duplex stainless steel S32750 has better corrosion resistance.