Evaluation of inkjet-printed spinel coatings on standard and surface nitrided ferritic stainless steels for interconnect application in solid oxide fuel cell devices

Abstract

Inkjet printing technology was employed for the application of protective layer coatings in SOFC metallic interconnects. Aqueous-based spinel coatings were inkjet-printed on standard and surface nitrided K41 ferritic stainless-steel substrates. Inkjet-printed substrates were exposed to high-temperature oxidation and Area Specific Resistance (ASR) tests for 1000 h at 700 °C in air with 3% volume humidity, simulating SOFC cathode environment. Performance of inkjet printed coatings and effect of nitriding stainless-steel substrates were evaluated based on chromium migration/retention and Area Specific Resistance. Sol-gel infiltration was introduced to develop a scaffold layer over the porous microstructure. With the ASR reduced to a level ∼60 mΩ cm2 and chromium concentration in the getter (cathode) material below 1 atomic%, close to the detection threshold, the protective layers produced via inkjet printing present a promising solution for SOFC interconnector applications.