A Study of the Effect of Velocity on Corrosion of Galvanic Couples in Seawater Using a Circling-Foil Apparatus.

摘要

A unique apparatus has been developed to study velocity effects on corrosion processes, and has been used initially to expose single metals and galvanic couples of some common marine structural materials in synthetic seawater electrolyte, under controlled hydrodynamic conditions at various relative velocities. The sample-holder in the apparatus has a standard foil profile, with a turbulence trip wire at the leading edge. Direct determinations of turbulence intensity, boundary layer thickness, and surface shear stress were made at various velocities, enabling correlations of hydrodynamic models with electrochemical data and other observations of corrosion behavior. The effects of velocity and potential distribution on average corrosion rates, and on the mode and distribution of corrosive attack and corrosion products, have been studied. (Author)