Design of High Corrosion Resistant Ni Alloy Using Electronic State Calculation

Abstract

Ni alloys are used as the prominent industrial material for heat-resistance and corrosion-resistance. Out of them, Inconel has excellent properties for high-temperature heat-resistant equipment as an excellent material for equipment such as ultrahigh-temperature electric furnace and or boiler. However, Ni alloys used in various areas contain high-priced metals such as Ta, Nb, or Re and their use have been limited to industrial sector so far due to the price incompetence. In this study, the alloy Ni–28Cr–4Mo–2Ti was designed by electronic state calculation by replacing the expensive material of Ta and Nb in Inconel 625 with Ti. In order to compare the corrosion properties, they were intentionally corroded in a furnace at 500 °C for 3 months and potentiodynamic polarization method was used to check the corrosion rate. The validity of the results was also confirmed by using the values of atomic radius and electronegativity. As a result, it was confirmed that the newly designed alloy had superior corrosion resistance at higher temperature than Inconel 625.