Study of effect of particle size on densification of copper during spark plasma sintering

The effect of particle size on the densification mechanism of as atomised copper powder during spark plasma sintering was investigated. In the temperature range 600-700°C and pressure range 20-30 MPa, consolidation of the powders is given by rearrangement, deformation, neck formation and minimal growth. Deformation and neck formation are enhanced by an increase in the particle size, since the current flow in the contact areas increases with the particle size. The actual pressure in the contact area, instead, does not change with the particle size. The extremely high and localised temperature on the contact points between particles leads to melting, giving rise to neck formation. The high temperature decreases towards the centre of the particle, allowing thermal softening and increasing the deformability of the particle core. © 2012 Institute of Materials, Minerals and Mining.