Fabrication and Characteristics of 8YSZ/Ni Functionally Graded Materials by Applying Spark Plasma Sintering Procedure

Functionally graded materials (FGM) in the form of layered structure consisting of yttria stabilized zirconia (YSZ) and nickel were fabricated by spark plasma sintering procedure. The relative density, linear shrinkage and Vickers hardness of each layer of graded materials were measured. The microstructure and the composition of these components were studied. The results obtained show that functionally graded materials produced by spark plasma sintering exhibited a low porosity level and consequently fully dense specimens. Also, the results demonstrate that the composition and microstructure of YSZ/Ni FGM have the expected gradient distribution. There are no macroscopic distinct interfaces in YSZ/Ni FGM due to the gradient change in components. This good continuity of microstructure can eliminate the disadvantage of traditional macroscopic interface in YSZ/Ni joint, and reflect the design idea of FGM. Vicker’s hardness of YSZ/Ni is lower than that of pure zirconia (YSZ) and increases by increasing the relative density of the layer of YSZ/Ni.