High-temperature corrosion model of Incoloy 800H alloy connected with Ni-201 in MgCl2–KCl heat transfer fluid

Abstract

Abstract Long-term dipping corrosion experiments on Incoloy 800H (800H) in molten eutectic MgCl 2 –KCl salt at 1,073 K with and without connection with Ni-201 alloy were carried out. While connecting with Ni-201 alloy, the corrosion rate of 800H was 4.47 ± 0.26 mg·cm −2 ·day −1 (10 −3.55±0.02 A·cm −2 ). However, the corrosion rate for the 800H that was not connected to the Ni-201 alloy was 3.00 ± 0.27 mg·cm −2 ·day −1 (10 −3.71±0.04 A·cm −2 ). Therefore, Ni-201 alloy accelerates the corrosion rate of 800H in the molten MgCl 2 –KCl salt while connecting to each other. In addition, based on the calculation of Gibbs energy of Ni–Fe–Cr alloy and exchange current density of 800H in MgCl 2 –KCl salt, a new Tafel model was developed to predict the corrosion rate of 800H alloys. The corrosion rate calculated by the new model is 10 −3.74 A·cm −2 , which agrees with the experimental data.