Corrosion Behavior of Metallic Materials in Organic Media Containing Hydrogen Chloride

An investigation has been performed into the general corrosion behavior of metallic materials in acid containing organic solutions. Media effects were investigated and found to considerably affect the dissolution process of metals. The metals and solvents used in this study were: Metals—Zn, Fe, Al, Cr-Ni steel; solvents—methanol, ethanol, 1-propanol, 1-butanol, acetone, ethyl acetate, diethyl ether, 1, 4-dioxane, vinylidene chloride, benzene (water as comparison). The solutions were acidified with HCl. Corrosion in acidic organic media can be much greater than in water. To evaluate corrosion conditions, it is necessary to know the physical-chemical properties of the medium. In the case of zinc, the dominant influence is the viscosity, which can be satisfactorily described by the function V_corr = k (1/kinemat.visc.). The rate determining step is, most probably, the transport of oxidant. In systems with iron, aluminum, and Cr-Ni steel, there is notable influence of electrolytic conductivity. The conductivity of about 10⁻³ S/cm represents a threshold value, above which the corrosion rate increases rapidly.