LaNbO_4 toughened NiO-Y2O_3 stabilized ZrO_2 composite for the anode support of planar solid oxide fuel cells

摘要

NiO-Y2O_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.