The first phase of this work evaluates the viscosity of WC–Co pastes.
The experiments conducted by Bouvard [15] show that the viscosity of
these mixtures exponentially increases with the density under isothermal
conditions, but it dramatically decreases during the conventional
sintering cycle. The need to evaluate this parameter is critical to characterize
the mixture in the extrusion process. In fact, in order to allow the
mixture to maintain a high viscosity and a plasticity degree suitable for
the forming step, it is necessary to add reduced binder (Co) amounts
[16] in the WC–Co compound. The viscosity evaluation is carried out
for different values of shear rate, by means of a testing fixture designed
and manufactured for these experiments