High-Temperature, Aqueous-Phase Diffusion of NaCl through Simulated Deposits of Corrosion Products

Aqueous-phase effective diffusion coefficients were measured for sodium chloride in simulated porous corrosion products using a modified diaphragm cell technique at temperatures from 25°C to 280°C. The effect of the pore structure on the measured diffusion coefficient was determined from the bulk diffusion coefficient at the experimental temperature. A tortuosity factor was calculated for each corrosion product as a function of temperature. The tortuosity factor was used with a bulk diffusion coefficient and porosity to estimate the transport rate of a solute specie in corrosion products at elevated temperatures and pressure.