Effect of chloride ion concentration on corrosion process of selective laser melted AlSi10Mg with different heat treatments studied by electrochemical noise

Abstract

The effect of chloride ion concentration on corrosion behavior of selective laser melted (SLMed) AlSi10Mg with different heat treatment (300 °C and 400 °C) was in-situ investigated by electrochemical noise (EN) technique and corrosion morphology observation. The EN signals were analyzed by noise resistance (Rn) analysis, wavelet analysis and recurrence quantification analysis (RQA). It was found that the corrosion rates of as-building and heat treated at 300 °C samples are close at the corrosion early stage when exposed to 0.1 M NaCl, while the corrosion resistance of the sample heat treated at 300 °C is lower than that of as-building sample during the whole test period when exposed to 1 M NaCl. Corrosion resistance of the sample heat treated at 400 °C is lowest in the two NaCl solutions. The relationship between the microstructures and the corrosion mechanisms is discussed. The main contribution of present study is to provide an alternative EN technique to in-situ study the corrosion behavior of SLMed AlSi10Mg and obtain some useful information, which is different from that obtained by traditional polarization curve and electrochemical impedance spectroscopy.