LaNbO4 toughened NiO–Y2O3 stabilized ZrO2 composite for the anode support of planar solid oxide fuel cells

NiO–Y 2 O 3 stabilized ZrO 2 (YSZ) composite is the state-of-the-art material for the anode support of planar solid oxide fuel cells (SOFCs). To improve its fracture toughness ( K C ), lanthanum orthoniobate LaNbO 4 is synthesized by the method of solid state reaction and added to the mixture of YSZ and NiO at the weight ratio of 47:53. The content of LaNbO 4 in the composite is in the range between 5 and 30 wt%. The microstructure of the composites is examined by scanning electron microscopy (SEM); and the chemical compatibility among the components is evaluated by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Vickers hardness test is performed for estimating the K C of the composites. The results indicate that the K C increases with the addition of LaNbO 4 in the composites; and the toughening effect is associated with the grain-refinement in the composite and the domain switch in the monoclinic LaNbO 4 .