Effect of Sodium Chromite on Oxygen in Sodium Analysis in a Stainless Steel System^★

In a non-isothermal flowing sodium/stainless steel system, iron, chromium, and nickel are dissolved from the high-temperature regions and deposited in the lower temperature regions because of supersaturation. Included in this process of mass transfer is the formation and decomposition of various transition metal and sodium double oxides. In addition, the formation of a double-oxide would also lower the oxygen activity in the sodium system if the double oxide is thermodynamically more stable than Na₂O. The main objective of this study is to assess the effect of double oxides, particularly sodium chromite (NaCrO₂), on the oxygen activity in a typical sodium/stainless steel system.