Residual stresses in the atmospheric plasma sprayed NiO/LDC anode of the metallic supported solid oxide fuel cells

In the spraying process, residual stresses are unavoidably developed in coatings due to the differences in thermal expansion coefficients, and cooling conditions between the coating and the substrate. A significant residual stress may lead to micro-cracks in the film or cause the film to peel off the substrate. Therefore, in this work, the biaxial residual stress states of a SOFC anode with various spraying conditions by using the “sin2ψ” technique of the XRD method were studied. The results show that the NiO/LDC coating on the porous Ni substrate with high temperature displayed the lowest compressive residual stress. The compressive residual stress in the NiO/LDC anode decreases with the increase of the Ni substrate temperature during the plasma spraying. In addition, the coating thickness didn't show the obvious effect on the residual stress. Moreover, the compressive stress will promote the tendency of coatings to debond or curve all the cell components.

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► NiO/LDC on the Ni substrate with higher temperature displayed lower compressive residual stress.
► Compressive residual stress in anode is decreased with the increase of substrate temperature.
► Compressive stress will promote the tendency of coating to debond or curve all the cell components.