Generation of surface texture on 2A50 aluminum alloy with electrochemical micromachining for tribological application

Aluminum alloy, as a lightweight structural material, has broad applications in aerospace, automotive, and military industries. However, its poor wear resistance limits its application in friction pairs of products. To improve the tribological performance of aluminum alloy, preparing surface texture like micro-pit array with electrochemical micromachining to reduce friction and wear is a promising strategy. Research on the electrochemical dissolution behavior of 2A50 aluminum alloy is critical to generate micro-pit array with high machining precision. However, the electrochemical dissolution behavior of 2A50 has not been thoroughly researched. This study focused on the electrochemical dissolution behavior of 2A50 in NaNO₃ and NaCl solutions under different conditions. Various methods were employed to investigate the electrochemical dissolution characteristics of 2A50 aluminum alloy, such as open circuit potential, potentiodynamic polarization curves, Tafel polarization curves, and electrochemical impedance spectroscopy. The results indicate that using a 10 wt%, 20 °C NaNO₃ solution as the electrolyte can enhance the machining accuracy of the micro-pit array by electrochemical micromachining. Ultimately, through-mask electrochemical micromachining was utilized to generate a micro-pit array on the surface of 2A50 aluminum alloy. The average diameter and depth of the micro-pit array are 111.4 μm and 11.9 μm, with ranges of 3.7 μm and 4.2 μm, and standard deviations of 0.8 μm and 1.2 μm, respectively. The friction test results indicate that the micro-pit array can effectively improve the wear resistance of 2A50 aluminum alloy.