Ferritic Stainless Steel Interconnect Silica Layer Reduction

The patent applies preliminary action by performing a pre-oxidation treatment during manufacturing to deliberately form and remove silica layers before the interconnect is put into service. This preliminary removal of silicon-rich surface layers prevents the formation of electrically resistive silica during subsequent fuel cell operation, thereby maintaining low contact resistivity while preserving the manufacturability benefits of ferritic stainless steel.

The patent converts the harmful effect of silicon migration into a beneficial outcome by utilizing the pre-oxidation treatment to deliberately form silica layers that are then removed. This process depletes silicon from the near-surface region, transforming the originally harmful silicon migration tendency into a controlled manufacturing step that prevents future silica formation and maintains electrical conductivity.

The patent merges the pre-oxidation treatment with existing manufacturing processes such as annealing or scale formation steps that are already part of the ferritic stainless steel production workflow. By combining the silicon-depleting pre-oxidation with these existing thermal processing steps, the patent reduces the need for additional separate processing operations while achieving the desired surface modification for low contact resistivity.