Effect of Graphene Nanosheets on Microstructure and Corrosion Resistance of ADC12 Alloy

The effect of graphene nanosheets (GNPs) on the microstructure and corrosion resistance of ADC12 alloy in HCl solution were researched by optical microscope, scanning electron microscope, energy-dispersive spectrometer, x-ray diffraction and electrochemical measurements. The microstructural evolution revealed that the addition of GNPs could significantly refine the α-Al, Si and β-Al5FeSi phases, thus optimizing the microstructure of ADC12 alloy. The results of electrochemical experiments demonstrated that the corrosion current density of ADC12-0.9 wt.% GNPs alloy (1.18 mA cm−2) was 62.7% lower than that of the matrix (3.17 mA cm−2), and the corrosion potential (− 534 mV) was 8.4% higher than that of ADC12 (− 579 mV). Moreover, the value of polarization resistance (70.74 Ω cm2) was highest when adding 0.9 wt.% GNPs, indicating the improved corrosion resistance. The results of immersion tests indicated that the corrosion rate of the ADC12-0.9 wt.% GNPs alloy (VM = 16.31 ± 0.81 mg cm−2 d−1) was 62.3% lower than that of the matrix (VM = 43.16 ± 1.69 mg cm−2 d−1). Moreover, the effect of GNPs on the micro-galvanic corrosion for ADC12 alloy was discussed.