Electrochemical Characteristics in Micro Area of ZL102 Aluminum Alloy in 3% NaCl Solution

Using scanning electrochemical microscopy (SECM), the corrosion behavior of ZL102 aluminum alloy in 3% NaCl (mass fraction) solution was investigated. The corrosion morphology was observed by optical microscopy and scanning electron microscopy (SEM), and the inclusions and corrosion products were analyzed by energy dispersive spectroscopy (EDS). The results show that the micro cell formed between intermetallic compound and matrix of ZL102 aluminum alloy. The potential of intermetallic compound was higher than that of the matrix, which resulted in the matrix preferential dissolution in 3% NaCl solution. The activity of aluminum alloy surface was not stable during the corrosion process because the smaller intermetallic compounds were easy to fall off due to the dissolution of surrounding matrix, and precipitated in other regions, and only the matrix around larger intermetallic compounds continuously dissolved, leading to pitting ultimately.