Pitting corrosion of aluminum in neutral chloride solutions under heat-transfer conditions

The effect of stirring the medium and heat-transferring on the pitting corrosion of a series of aluminum alloys in neutral chloride-containing solutions was studied under the controlled conditions of free or force convection and laminar or turbulent flow of the Liquid. Basic regularities of pitting initiation and growth were found as the functions of chloride concentration, Liquid flow velocity, temperature of the metallic wall, temperature of the liquid, and temperature drop within the wall layer. Essentially different effects of the aforesaid factors on pitting-corrosion of aluminum alloys and stainless steels were detected. The heat-transfer conditions were shown to have a significant effect on the characteristic pitting-corrosion potentials, as well as on the topography and morphology of pits. The presented data unambiguously testify that the corrosion behavior of metals and alloys cannot be reduced to the effect of only one of the aforementioned factors, but is a function of the whole set of electrochemical, hydrodynamical, heat- and mass-transfer phenomena.