Electrochemical study of the pitting corrosion of aluminium and its alloys—I. Determination of critical pitting and protection potentials

Abstract The effects of different experimental parameters influencing the determination of critical pitting and protection potentials of aluminium and its alloys are discussed. The simplest mechanical sample preparation, 0.05 mol dm −3 NaCl 1 mol dm −3 Na 2 SO 4 test solution, CV polarization with 10-0.1 mV s −1 sweep rate are the suitable experimental conditions. The standard deviation of the characteristic potentials are different; it is less than 5 mV at protection potential and less than 20 mV in the case of pitting potential. The effect of intermetallic phase composition is investigated in a certain range.