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

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<middle dot>cm(-2)<middle dot>day(-1) (10(-3.55 +/- 0.02) A<middle dot>cm(-2)). However, the corrosion rate for the 800H that was not connected to the Ni-201 alloy was 3.00 +/- 0.27 mg<middle dot>cm(-2)<middle dot>day(-1) (10(-3.71 +/- 0.04) A<middle dot>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<middle dot>cm(-2), which agrees with the experimental data.