Electric field in SPS: geometry and pulsed current effects

Electrical heating of the graphite die and punch assembly is a unique feature of the spark plasma sintering (SPS) process. The high currents needed to heat the die, despite its low resistance, can produce an electric field across the ceramic specimens that may be enough to induce field assisted sintering. Despite the large number of publications of SPS, the electric field intensity has not been accounted in previous investigations. A FEM model is employed to quantify the magnitude of electric field applied during sintering across zirconia sample. We show that the electric field depends most critically on the ratio of the outer and inner diameter of the die. We also report that the intensity of the electric field across the sintering sample is significantly affected by duty cycle of the pulsed current.