Effect of Heat Treatment on Thermal Sprayed Protective Oxides for SOFC Metallic Interconnects
For metallic interconnects used for SOFC applications, several oxides such as LaMnO3 and LaCrO3-based perovskite oxides and (Mn,Co)3O4, (MCO), with spinel structure have been used to form protective layer for metallic interconnects. However, the temperature during thermal spraying may be high enough to change the crystal structure and conductivity of protective oxides. The heat treatment is believed to be an appropriate method to obtain adequate properties for protective oxide. Thus, the after-spray treatment will play an important role for metallic interconnects to obtain desired electrical properties. In this study, the high-temperature ferritic stainless steel Crofer 22H and nickel-chromium alloy Inconel 625 were first thermally sprayed with oxides with perovskite and spinel structures.
The objective of this work is to investigate the effect of after-spray treatment on the crystal structure and conductivity of the sprayed oxide. The crystal structure, morphology and electrical conduction of interconnect with sprayed oxide films will be examined by using XRD, FESEM and resistance measurement.