Effect of heat flux on metal corrosion in non-boiling media: testing system, heat transfer simulations, and corrosion study on Al alloy

Abstract

ABSTRACT A dual-circulation testing system was constructed to study the effect of heat flux density (q, −22.28 ∼ +22.54 kW m-2) on the corrosion of an Al–Cu–Mg–Mn alloy in 0.5 M H2SO4 at a constant metal surface temperature (50°C) under different controlling heat transfer states. Their heat transfer parameters were determined quantitatively by COMSOL simulation to keep them except q in constant, highlighting the influence of q on metal corrosion. Compared with the q = 0 condition, the positive heat flux (q > 0) improved the surface layer performance of the Al alloy to inhibit its anodic corrosion process, decreasing its corrosion current density (i corr) by 56% with increasing q to 22.54 kW m-2. While q < 0, the opposite effect occurred, increasing its i corr by 52% at q = −22.28 kW m-2. Heat flux also changed the corrosion reaction’s apparent effective activation energy (E a) and pre-factor, and E a played a dominating role in changing i corr.