Effect of the current pulse pattern during heating in a spark plasma sintering device: Experimental and numerical modeling approaches

The operating features of the current generator during Spark Plasma Sintering (SPS) process are carefully studied thanks to the use of a specific instrumentation. It is shown that the current pulse pattern characteristics identified here for a Dr. Sinter 825 apparatus are transposable to other Dr. Sinter devices whatever their electrical powers. Particularly, thanks to the highlighting of the characteristic logarithmic decrease of the ratio of rms to average electrical values, it is possible, for users of SPS devices, to determine the imposed rms intensity from the average intensity measured by the galvanometer of the apparatus without additional electrical instrumentation. Moreover, as shown by a numerical approach, the delivered rms intensity directly correlated to the pulse pattern characteristics is a key parameter that controls the heating process induced by the Joule effect. Hence, a reliable numerical model is established with an accurate assessment of the heating rate and of the thermal gradients.