Simulation of Contact Resistances Influence on Temperature Distribution during SPS Experiments

The behavior of the Spark Plasma Sintering/Synthesis (SPS) apparatus, which represents an effective tool for sintering/synthesizing advanced materials, is simulated in this work. A step-by-step heuristic procedure is proposed since several, concomitant physico-chemical phenomena, for example heat transfer and generation, electric current transport, and stress-strain mechanics along with chemical transformation and sintering, take place during SPS processes. In this work we consider the SPS behavior of specific sample configurations characterized by the absence of powders. This approach permits to determine the electric and thermal resistances experimentally evidenced in the horizontal contacts between stainless steel electrodes and graphite spacers as functions of temperature and applied mechanical load. Horizontal contact resistances between graphite elements are experimentally found to be negligible and, accordingly, they are not modeled. Model reliability is tested by comparing numerical simulations with experimental data obtained at operating conditions far from those adopted during fitting procedure of unknown parameters. The proposed model can be successfully compared from a quantitative point of view to the measured temperature, voltage once rms current, geometry are taken into account.