Effect of Cu content on the corrosion of Al‐Si eutectic alloys in acidic solutions

Abstract

Purpose The purpose of this paper is to understand corrosion behavior of different Cu‐containing Al‐Si‐x% Cu alloys (x: 1 wt% Cu, 2 wt% Cu, 3 wt% Cu, 4 wt% Cu, and 5 wt% Cu) in 0.1 M HCl and 0.1 M H 2 SO 4 . Design/methodology/approach Potentiodynamic, chronoamperometric and impedance measurements were applied to specimens to obtain their electrochemical characteristics. For the long‐term analyses, hydrogen evolution with immersion time ( V ‐ t ) was measured. The corroded surfaces of the alloys were investigated using scanning electron microscopy (SEM) to understand the corrosion mechanism. Findings All experimental investigations showed that the corrosion resistance of alloys increased with increasing Cu content in the alloys. Research limitations/implications Cu‐containing aluminum alloys are age‐hardenable alloys. The corrosion behaviour of these alloys can be changed by heat treatment. Corrosion test results for the heat treated and aged alloys will be discussed in another study. Originality/value Al‐Si‐Cu alloys are widely used in the automobile industry and the corrosion behaviour of these alloys has a great importance on the service life of these materials. Understanding the effect of copper and the corrosion mechanism of these alloys will be helpful in predicting and prolonging the service life of these materials.