Ferritic stainless steels are the most promising low-cost interconnect material for solid oxide fuel cells. The performances of two prospective interconnect alloys, 430 and 441, differ in dual atmosphere exposures, in which the alloy is exposed to hydrogen on one side and air on the other. The two alloys are similar in composition, with the same chromium content, but alloy 441 contains small amounts of niobium and titanium. The differences in behavior are typically attributed to the niobium addition, so in this work a diffusion treatment was used to introduce niobium into alloy 430, and the oxidation behavior of the niobium-doped alloy 430 were compared with those of undoped alloy 430 and alloy 441.