Self-diffusion in cr₂o₃III. Chromium and oxygen grain-boundary diffusion in polycrystals

Nickel-plating for active metal dissolution resistance in molten fluoride salts

“…11) that an interlayer of Cr 2 O 3 between the substrate alloy and the Ni-plating could dramatically reduce interdiffusion of Cr, Fe, and Ni between the substrate and the Ni-plating [6]. The literature indicates that diffusion rates of Cr and Fe in Cr 2 O 3 are about four orders of magnitude lower than the Cr diffusion rates observed in the Ni-plating [34,35]. This observation provides an avenue for a solution to mitigating corrosion of high Cr alloys in molten fluoride salts.…”

Low Valence Cation Doping of Bulk Cr2O3: Charge Compensation and Oxygen Vacancy Formation

“…29,45 More recent studies have however indicated that oxygen diffusion is more facile, in particular along grain boundaries, thus indicating that structural defects as well as doping in Cr 2 O 3 can improve its oxygen mobility. [46][47][48] The introduction of holes through incorporating a LV dopant will lead to spontaneous formation of oxygen vacancies to compensate the lower oxidation state of the dopant compared to the host. [49][50][51][52] The resulting absence of oxygen in the lattice after the release of oxygen can be experimentally observed, as the vacancy cannot be annealed in the presence of oxygen.…”

Oxygen reduction on strontium-doped LaMnO3 cathodes in the absence and presence of an iron–chromium alloy interconnect

“…It is well-known that chromium oxide is a very poor conductor of oxygen ions. The oxygen self-diffusion coefficient in Cr 2 O 3 single crystals is ∼10 −18 cm 2 s −1 at 1100 • C [42] and in Cr 2 O 3 polycrystals is ∼10 −13 cm 2 s −1 at 1100 • C [43], i.e., significantly lower than 10 −8 to 10 −7 cm 2 s −2 at 900 • C reported for YSZ electrolytes [44,45]. Therefore, the migration of oxygen ions into the electrolyte will be dominated by the diffusion of oxygen through the solid Cr 2 O 3 and (Cr,Mn) 3 O 4 deposit layer, and will cause a significant increase in electrode resistance to the migration of oxygen ions into the YSZ electrolyte.…”