Wet powder spraying - A versatile and highly effective technique for the application of spinel-type protective coatings on SOC interconnects

Chromia-forming metallic interconnects used for solid oxide cells require protective coatings to prevent chro-mium poisoning of other cell components. This study focuses on Mn1.0Co1.9Fe0.1O4-coated Crofer 22 H in-terconnects fabricated by wet powder spraying, which is a versatile, cost-effective, and scalable coating technique. The investigation and fine-tuning of relevant parameters along the process chain provide a funda-mental understanding of their impact on coating quality and thermomechanical stability. The correlation with cross-sectional analysis and area-specific contact resistance (ASR) measurements supports the parameter eval-uation. Mid-term thermal testing demonstrates excellent chromium retention, as well as chemical and me-chanical stability of the protective layer on real component interconnect substrates. With an ASR below 10 m omega cm2 after 1000 h at 800 degrees C, wet powder spraying represents a viable alternative to established but more expensive processes.