The Energy Balance during Plasma Sintering

High heating rate during plasma sintering of metallic powders, mainly the supersolidus, can lead to better properties of the sintered material. In this work, powders with different thermal conductivities (Cu and Ni) were plasma sintered using both, planar discharge and hollow cathode discharge (HCD) configuration. The thermal evolution was studied using three thermocouples inserted inside the samples at different depths. Thermal gradient and the heating rate were measured as a function of the source power, discharge configuration, pressure and thermal conductivity of the material. We have observed that the thermal gradient changed greatly with the discharge configuration. The thermal difference between most profound and most shallow inserted thermocouple in Cu samples was around 30 °C for both planar and HCD discharge configuration. Ni samples and the planar configuration gave thermal difference of 70°C while for HCD configuration thermal difference went superior 140 °C. For this last case, heating rate of 300 °C/min was obtained.