Processing and characterization of WC-10Ni/-7Ni-3Cr based yttria stabilized zirconia spark plasma sintered composites

The mechanical properties and wet sliding wear behavior of spark plasma sintered WC based composites consolidated using 10Ni/7Ni-3Cr (metallic binders) and varied wt.% (15 and 20%) zirconia stabilized with yttria (ceramic binder) as mixed binder additives were investigated. Relative density measurement, SEM analysis, hardness and Palmquist toughness characterization were used to assess the properties of the produced composites. The results show that the use of mixtures of 10Ni, 7Ni-3Cr and yttria stabilized zirconia binder additives for the consolidation of the WC based composites yielded relative densities above 94%. Significant drop in hardness values was observed in the sintered composites with the addition of 15 and 20% zirconia. But the Palmquist toughness improved with the addition of zirconia for both composite grades. The fracture toughness for the WC-10Ni based yttria stabilized zirconia composites appeared to be invariant to the addition of zirconia while the WC-7Ni-3Cr composite grades showed a slight improvement in the fracture toughness with an increase in the zirconia content. The fracture toughness of the WC-10Ni based yttria stabilized zirconia composites was slightly superior to that of the WC-7Ni-3Cr based yttria stabilized zirconia composites. The addition of zirconia resulted in a significant reduction of the coefficient of friction of the WC-10Ni based yttria stabilized zirconia composites but resulted in the increase of the coefficient of friction of the WC-7Ni-3Cr based yttria stabilized zirconia composites.