ELECTRICAL AND MECHANICAL PERFORMANCE OF ZIRCONIA-NICKEL FUNCTIONALLY GRADED MATERIALS

In the present work, six-layered (Zirconia/Nickel) functionally graded materials were fabricated via powder metallurgy technique (PMT). The microstructure, fracture surface and the elemental analysis of the prepared components were studied, and their linear shrinkage, electrical conductivity, fracture toughness and Vickers hardness were evaluated. The results show that the linear shrinkage of the non-graded composites was reduced with the nickel content. The electrical conductivity of the YSZ/Ni was strongly depended on its nickel content. The electrical conductivity as a function of nickel content had a typical ‘S’ shape curve. Vickers’s hardness of YSZ/Ni was lower than that of pure ceramic YSZ and was reduced by decreasing the density of the layer of YSZ/Ni FGM, which was attributed to the pores in intermediate layers in the FGM after sintering stage. Also, the fracture toughness obtained by the non-graded composite increases with an increase in nickel content from 0 % to 50% Ni. The functionally graded materials exhibited a high fracture toughness (31 MPa m1/2) compared to the non-graded composite.