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

Abstract

Long-term dipping corrosion experiments on Incoloy 800H (800H) in molten eutectic MgCl2–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 MgCl2–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 MgCl2–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.

Keywords

• incoloy 800h
• mgcl2–kcl
• corrosion
• ni–fe–cr alloy
• ni crucible