Friction and wear performance of an aluminium alloy in artificial seawater

The corrosion wear behaviours of an aluminium alloy 2024Al flat specimen against a 440C stainless-steel counter ball specimen were evaluated in artificial seawater by using a ballon-flat configuration with 300 mu m amplitude at room temperature for 1 h. Reference experiments were also performed in distilled water. The worn surface of the specimen was observed using scanning electron microscopy. The three-dimensional morphology and wear volume loss were determined using a non-contact optical profilometer. Potentiodynamic anodic polarization was used to measure the corrosion behaviours of 2024Al before and after the corrosion wear test. The influences of the aqueous medium on the corrosion resistance, coefficient of friction, and wear loss were analysed. Results show that 2024Al exhibits a dominant pitting corrosion mechanism in seawater and corrosion is accelerated by wear. Seawater can reduce the friction coefficient, whereas the wear loss in seawater is higher than that in distilled water, which can be attributed to a higher Cl-percentage. This implies that the wear is accelerated by corrosion. There is a positive synergism between corrosion and wear for 2024Al sliding in seawater. The wear mechanism of 2024Al is dominant corrosion fatigue in seawater due to the distinct electrochemical reaction. The profile of wear concave gradually changes from 'V' shape into 'U' shape with the increase of load or frequency.