Development of plasma sprayed molybdenum carbide-based anode layers with various metal oxides for SOFC

Air plasma sprayed (APS) coatings provide an ability to deposit a range of novel fuel cell materials at competitive costs. This work develops three separate types of composite anodes (Mo-Mo2C/Al2O3, Mo-Mo2C/ZrO2, Mo-Mo2C/TiO2) using a combination of APS process parameters on Hastelloy ® X for application in intermediate temperature proton conducting solid oxide fuel cells. Commercially available carbide of molybdenum powder catalyst (Mo-Mo2C) and three metal oxides (Al2O3, ZrO2, TiO2) were used to prepare three separate composite feedstock powders to fabricate three different anodes. Each of the modified composition anode feedstock powders included a stoichiometric weight ratio of 0.8:0.2. The coatings were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, nanoindentation and conductivity. We report herein that three optimized anode layers of thicknesses between 200 to 300 μm and porosity as high as 20% for Mo-Mo2C/Al2O3 (250 μm thick) and Mo-Mo2C/TiO2 (300 μm thick) and 17% for MoMo2C/ZrO2 (220 μm thick), controllable by a selection of the APS process parameters with no addition of sacrificial pore-forming material. The nanohardness results indicate the upper