Pulse analysis and electric contact measurements in spark plasma sintering

• Shape of the pulse sequence depends on the electric power required to heat the SPS tools.
• The strong role of the electric contact (EC) between the parts of the SPS device is evidenced.
• Dœhlert experimental design is used to determine the EC behavior with pressure and temperature

In order to model the current density distribution and the temperature changes of the tools used during a spark-plasma-sintering (SPS) cycle, the variation of the power delivered by an SPS machine and the graphite-Papyex®-graphite electrical contacts were studied experimentally. The electric device was also characterized; in particular current pulse characteristics and their behavior with time were studied in various conditions of temperature, pulses sequences, materials and total electric power dissipated. It is well known that the performance of an electric contact is dependent on the applied pressure and the temperature. First, by varying the pressure during the SPS cycle the effect of the electric contacts is clearly seen. Secondly, in order to determine the behavior of such contacts experimentally over a pressure range of 10–50 MPa and temperatures of 50–800 °C, a Dœhlert experimental design was used.