A fluid-flow approach in oxidation evaluation of SUS 430 steels coated by Fe/Mn-modified MnCo for solid oxide fuel cell application

Abstract

The Fe/Mn-modified MneCo spinel oxides (MCO) are coated on SUS430 interconnect to protect against oxidation and chromium diffusion by wet spray followed by nitrate solution impregnation for intermediate-temperature solid oxide fuel cell (IT-SOFC) application. 1000 h oxidation tests at 800 C show that the FeMCO-coated sample have the minimum parabolic rate constant (9.02 10 7 mg 2 cm 4 s 1 ), which is lower than half of the uncoated sample. The area-specific resistance (ASR) of the FeMCO-coated sample is 6.41 mUcm at 800 C after 1000 h oxidation, which is much lower than the MCO sample (19.38 mU cm ) and the uncoated sample (186.84 mU cm 2 ). The samples microstructures are examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Based on a novel approach, the dimensionless fluid numbers are related to the high-temperature conductivity of coated interconnects, and the inward diffusion of oxygen is introduced as the limiting factor for oxide-scale growth of coated interconnects.