Study on the galvanic corrosion of aluminum alloy single bolted lap joints in simulated atmospheres

The corrosion behavior of galvanic couples covered by a 0.5 mm thick film using a homemade electrochemical measurement device has been researched in this work. The potential distribution and current density of lap joints (bare and coating damaged) in the thin layer electrolyte have been calculated using the boundary element method (BEM). The results show that the potential of 2A12 aluminum alloy plates as an anode shifted positively after lapping. The degree of anodic polarization and the corrosion rates reached the highest values in the regions around the bolts and then decreased on either side. The corrosion rate is closely related to the coating damage area; the smaller the damage area is, the larger the corrosion rate in the region of coating damage. The results of simulations conform to reality. The corrosion behavior of galvanic couples covered by a 0.5 mm thick film has been researched in this work. The potential distribution and current density of lap joints (bare and coating damaged) in the thin layer electrolyte have been calculated using BEM. The results show that the potential of 2A12 aluminum alloy plates as an anode shifted positively after lapping.