Abstract:Electrochemical tests were undertaken to determine the optimum conditions in seawater for corrosion protection of friction stir-welded 5083-O Al alloy. Polarization trend observations show that the limiting potential that avoids the effects of hydrogen embrittlement is −1.6 V, corresponding to the crossover point between concentration polarization and activation polarization. However, the optimum protection potential is between −1.5 and −0.7 V since the current density at these values is low in the potentiostatic tests. When a galvanic cell is formed in the seawater, the welds exhibit electrochemically stable trends. Welded parts in galvanic tests with various area ratios are stable and have excellent anticorrosion characteristics.

Key words: 5083-O Al alloy; electrochemical test; polarization; hydrogen embrittlement; optimum protection potential