Anodic behavior of silicon-containing aluminum alloys in NaCl electrolyte

Abstract

The electrochemical and corrosion characteristics of silicon-modified aluminum alloy were investigated in a NaCl environment using a potentiostatic method in a potentiodynamic regime. The rate of potential change during the sweep was 2 mV/s. The obtained dependences of the free corrosion potential on time for the initial aluminum and silicon-containing alloys demonstrate its shift towards more positive values, which indicates an increase in the material's resistance to corrosion. It has been established that an increase in the silicon content in the alloy leads to a positive shift in the potentials of free corrosion, repassivation, and the onset of pitting failure. At the same time, an increase in the concentration of chloride ions in the NaCl solution causes the opposite effect – the electrochemical potential of aluminum alloys with silicon shifts to the negative region. This is accompanied by an increase in the rate of corrosion processes, regardless of the alloy composition, which confirms the aggressive effect of chlorides on aluminum materials. The addition of silicon in various concentrations increases the corrosion resistance of A6 grade aluminum alloy, providing an improvement of 8-10% compared to the starting material.