Contact resistances in spark plasma sintering: From in-situ and ex-situ determinations to an extended model for the scale up of the process

摘要

tHeating in spark plasma sintering is a key point of this manufacturing process that requires advancedsimulation to predict the thermal gradients present during the process and adjust them. Electric andthermal contact resistances have a prominent role in these gradients. Their determination is difficult asthey vary with pressure and temperature. A calibration method is used to determine all of the contactresistances present within tools of different sizes. Ex situ measurements were also performed to validatethe results of the in-situ calibrations. An extended predictive and scalable contacts model was developedand reveals the great importance and diversity of the contact resistances responsible for the generalheating of the column and high thermal gradients between the parts. The ex/in situ comparison highlightsa high lateral thermal contact resistance and the presence of a possible phenomenon of electric currentfacilitation across the lateral interface for the high temperatures.