Corrosion Wear Behavior of Al-Bronzes in 3.5% NaCl Solution

The corrosion wear behaviors of two aluminum bronzes, Cu-14Al-X and QAl9-4, in 3.5% NaCl solution were investigated on a pin-on-block reciprocating tester. It was found that the wear loss of the bronzes in 3.5% NaCl solution was lower than that in water and in air, i.e., it exhibited "negative" synergy between corrosion and wear. To understand the corrosion wear mechanism of the bronzes, the corrosion rate and polarization curves of Cu-14Al-X and QAl9-4 in 3.5% NaCl solution were determined. The worn surfaces of the specimens were examined, and the wear tracks were measured using scanning electron microscopy. The corrosion patinas formed on the specimen surfaces were studied with x-ray photoelectron spectroscopy and electron probe microanalysis. The corrosive solution was shown to play an important role in cooling of the specimen surfaces during the wear, thus preventing the specimen's surface hardness from being reducing, induced by frictional heat during the sliding wear. On the other hand, the bronzes suffered from dealloying corrosion; a noble copper subsurface and patina formed on the specimen surface in the corrosive solution, which had a passive function for further corrosion. The noble copper subsurface experienced strain hardening during the corrosion wear, resulting in an increase of the surface hardness and thus an increase in wear resistance.