Corrosive wear of aluminium alloy in presence of phosphate

Abstract

The effect of phosphate on the tribocorrosion of aluminium D16T (AA 2024 equivalent) alloy in synthetic acid rain was studied. It was established that an extract of modified zinc phosphate increases the resistance of aluminium alloy to corrosion and mechanical wear, which is confirmed by the reductions in its polarisation current, friction coefficient against a ceramic counter body and erosion track dimensions. Electrochemical impedance results confirm the decrease in the corrosion rate of the rubbing surface of the aluminium alloy in the presence of phosphate. The charge transfer resistance of aluminium in the track area was found to be 1·65 times higher due to the formation of a conversion film in the phosphate containing solution. Precipitation of the phosphate film on the wear track area is accelerated due to the mechanical activation of aluminium alloy and its anodic polarisation at places of local destruction of oxide film.