Polarization Curve Measurement in High Purity Water at Elevated Temperatures

A polarization technique in high purity water at elevated temperature was studied for corrosion research on boiling water reactor (BWR) materials. A potentiostat with a dynamic potential drop (IR drop) compensator was evaluated in high-resistance solution that simulated high-purity water systems at both room temperature and 290 C. Potentiodynamical polarization curves in the systems were successfully obtained, in which potential scan rate was kept constant by eliminating the IR drop between working and reference electrodes. Using the technique, polarization curves were measured on AISI 304 stainless steel (SS) in high-purity water at elevated temperatures and on different materials in 290 C high-purity water. The curves obtained in high-purity water were different from those obtained in a widely used electrolyte of Na₂SO₄ solution.