Neutron diffraction residual strain measurements of molybdenum carbide-based solid oxide fuel cell anode layers with metal oxides on Hastelloy X.
Faisal, Nadimul Haque
Prathuru, Anil Kumar
Katikaneni, Sai P.
Goosen, Mattheus F. A.
Zhang, Shu Yan
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FAISAL, N.H., AHMED, R., PRATHURU, A.K., KATIKANENI, S.P., GOOSEN, M.F.A. and ZHANG, S-Y. 2018. Neutron diffraction residual strain measurements of molybdenum carbide-based solid oxide fuel cell anode layers with metal oxides on Hastelloy X. Experimental mechanics [online], 58(4), pages 585-603. Available from: https://doi.org/10.1007/s11340-017-0298-7
Thermal spray deposition processes impart residual stress in layered Solid Oxide Fuel Cells (SOFC) materials and hence influence the durability and efficiency of the cell. The current study which is the first of its kind, reports results on using a neutron diffraction technique, to non-destructively evaluate the through thickness strain measurement in plasma sprayed (as-sprayed) anode layer coatings on Hastelloy®X substrate. Through thickness neutron diffraction residual strain measurements has been done on three different anode coatings (Mo-Mo2C/Al2O3, Mo-Mo2C/ZrO2 and Mo-Mo2C/TiO2) using the vertical scan mode. The three anode coatings (developed through optimized process parameters) investigated had porosities as high as 20%, with thicknesses between 200 æm to 300 æm deposited on 4.76 mm thick Hastelloy®X substrate discs of 20 mm diameter. The results show that the through thickness residual strain in all three anodes was different for different crystallographic planes but was on average it was tensile. Other measurements includes X-ray diffraction, nanoindentation and SEM microscopy. As the anode layer microstructures are complex (includes bi-layer alternate phases), non-destructive characterisation of residual strain, e.g. using neutron diffraction, provides a useful measure of through thickness strain profile without altering the stress field in the SOFC electrode assembly.