Experimental Investigation of Electric Contact Resistance in Spark Plasma Sintering Tooling Setup

An experimental investigation on electric contact resistance in the tooling utilized in spark plasma sintering (SPS) is conducted. Two different SPS regimes are operated without the presence of processed powder to obtain the punch–punch (horizontal) and punch–die (vertical) contact resistance assessments separately. The processing temperature and applied pressure are considered to be the main factors that affect the contact resistance. These effects are analyzed by performing experiments at a maximum temperature of 1600°C with constant heating rate of 100°C/min. The applied pressure is ranging from 20 to 60 MPa and a 1 min holding time‐step is used to ensure stable measurements. It is shown that the contact resistance goes down as the temperature ramps up. An increase in the pressure leads to a decrease in the contact resistance. The mechanisms that cause these variations in the contact resistance are discussed. The dependence of assessed contact resistance of the utilized SPS system on the processing temperature and applied pressure is analytically described based on the regression analysis of the collected experimental data. A finite‐element simulation based on the obtained experimental results evidences that the electric contact resistance dominates the temperature evolution. The obtained results are of significant importance for modeling and optimization of SPS processes.