Corrosion at Metal InterfacesA Study of Corrosion Rate and Solution Properties, Including Electrical Conductance, Viscosity, and Density

Abstract

In this paper, we attempt to correlate the rate of corrosion at the metal surface with bulk solution properties such as electrical conductance, viscosity, and density. The premise is that the process solution environment within the pipe or refinery equipment controls the severity of the corrosion at the metal surface. Furthermore, the migration of a protonated amine to the metal surface (instead of a proton in acid solutions) is the rate-determining step. For this study, the corrosion rate and solution properties of a single neutralizer salt (DEA·HCl) plus ammonium chloride, were examined more closely at fixed temperature, pressure, and composition. The metallurgy was restricted to carbon steel. Metal coupons of the same geometry and size were used to collect corrosion rate data in a nonflowing static environment. Under such conditions, the experimental data support the hypothesis that the corrosion rate at the metal surface is strongly influenced by the diffusion of the protonated amine. Diffusion, like ...