A Novel Thermomechanical Processing Route to Fabricate ODS Ferritic Stainless Steel Interconnects and Their Oxidation Behavior

Oxide dispersion-strengthened AISI 430 alloy was fabricated using a novel thermomechanical processing route for potential application as interconnect in solid oxide fuel cells. The process can be termed as reverse friction deposition wherein the final product is formed by curling up as a seamless tube on the surface of the parent rod which is used as a consumable tool in a friction stir welding machine. The oxide dispersion alloy is obtained by incorporating 8mol% yttria-stabilized zirconia powder in drilled holes in the rod. The number and spatial distribution of holes were optimized for a sound product and uniform distribution of the particles. The oxidation behavior of the formed tube was remarkably different from that of the parent rod. The dispersion of zirconia particles on the outer surface of the tube retards Cr diffusion owing to their grain boundary pinning effect which also refines the Fe2O3 crystal size. (Cr, Mn)O-4 spinel, which is known to be electrically conductive, formed in the inner surface of the tube. The tube thus can be used as an interconnect in tubular solid oxide fuel cells and potentially prevent Cr poisoning of the cathode.Graphical Abstract [GRAPHICS] .