Current distribution and neck growth during spark plasma sintering conductive powder

Abstract

The evolution of the sintering neck sizes was observed in experiments on the conductive powder particles, based on which a model that describes the distributions of the current density and the temperature increase in the spark plasma sintering (SPS) process was developed. The simulations show that the sintering neck with smaller size grows prior to the neck with larger size. The reason is that the current density at the smaller necks is higher than that at the larger necks, hence there is a higher temperature increase at the same sintering stage. As a consequence, the neck size distribution becomes homogeneous with the densification process. A unique 'self-adjusting' mechanism for the neck growth was proposed for the SPS process, which explains the advantageous features of SPS densification.