Tribocorrosion behavior of aluminum alloys in 3.5 wt% NaCl solution
Jin Du, Linlan Hu, Meng Chen, Jian Sun, Qinghua Song, Jinkun Xiao
Abstract
The tribocorrosion behaviors of 2024-T4, 5052-H112, 6061-T6 and 7075-T6 aluminum alloys were investigated in 3.5 wt% NaCl solution under open circuit potential (OCP) and −1.5V Ag/AgCl conditions, as well as compared with dry sliding. The phases of the aluminum alloys were evaluated by X-ray diffraction. The morphology and passivation products of the worn surface were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy methods. Tribocorrosion tests were performed using a reciprocating ball-on-flat tribometer equipped with a three-electrode cell system. Results indicate that the tribocorrosion process involves dual interactions of electrochemical and mechanical forces. Friction exacerbates the corrosion tendency of all aluminum alloys. The E corr, I corr values of 2024-T4 in potentiodynamic polarization test are −1.09 V Ag/AgCl and 30.92 μA/cm 2 , showing the best corrosion resistance during the tribocorrosion tests. The wear rates of 7075-T6 under dry sliding, OCP and −1.5 V Ag/AgCl are 2.11 × 10 −3 , 1.09 × 10 −3 and 0.56 × 10 −3 mm 3 /N·m, demonstrating the best wear resistance. The dry sliding and tribocorrosion mechanisms of aluminum alloys were also discussed.