| 5383 aluminum alloy has been widely used in ocean engineering, because of its excellent mechanical properties.However domestic researchers mastered less systematic data of the material’s corrosion behavior in marine environment, so there is an urgent need to carry out the related research work. This paper adopts the electrochemical polarization curve and electrochemical noise (EN), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) to study the corrosion behavior of 5383 aluminum alloy in simulated seawater, drawn the following conclusions:(1) No matter where 5383 aluminum alloy is whether static seawater or flowing seawater, its corrosion resistant performance showed gradual decline with the prolonging of corrosion time, but the corrosion resistant performance relatively different at different stages.(2) The corrosion resistant performance in flowing seawater of 5383 aluminum alloy will be better than that of the same phase in static seawater with the extension of corrosion time, and the control step of corrosion process was cathodic process.(3) The corrosion behavior of 5383 aluminum alloy in the static seawater can be divided into four distinct stages:a) at the primal stage, there existed two obvious capacitive reactance characteristics in the high frequency and low frequency range of the EIS. Reaction resistance Rt, passivation membrane resistance Rp decreased gradually, and the electric double layer capacitance Cdl showed a trend of increasing with the prolong of corrosion time. These indicated a large number of aggressive ions (Cl-) in simulated seawater attacking on electrode surface and giving rise to active points dissolve and causing pitting corrosion; b) at the second stage, capacitive reactance arcs in the high frequency were greater than in low frequency. Rt, Rp, increased gradually, Cdl showed a trend of decreasing, these showed that the corrosion products forming a incomplete protective film and this protective film played a certain protective effect on the substrate; c) at the transition period, the low frequency capacitive reactance arc blurred gradually, Rt, Cdl varied, showed that corrosion product film in dynamic change; d) at the later stage, EIS, Rt, and Cdl kept stable.(4) The corrosion behavior of 5383 aluminum alloy in the flowing simulated seawater also can be divided into four distinct stages:a) at the primal stage, it has the similar corrosion behavior with static seawater, but shorter duration, showed the degree of corrosion on the 5383 aluminum alloy was more serious in flowing simulated seawater; b) at the second stage, there existed obvious capacitive reactance characteristics in the high frequency range of EIS and the inductive reactance characteristics blurred in the low frequency range of EIS, Rt, Rp varied, showed that flowing simulated seawater accelerating the formation and dissolution of corrosion product film; c) at the transition period, there existed obvious capacitive reactance characteristics in the high frequency range of EIS and the capacitive reactance characteristics blurred in the low frequency range of EIS, Rt varied and Rp increased gradually, showed that flowing simulated seawater contributing to the formation of corrosion product film; d) at the later stage, there existed two obvious capacitive reactance characteristics in the high frequency and low frequency range of the EIS, corrosion potential stable basically, Rt and Rp were increasing gradually with the time extension, showed that surface corrosion products of 5383 aluminum alloy accumulating gradually and played a protective effect on matrix, compared with static seawater the corrosion resistant performance of 5383 aluminum alloy was better at this stage. |
