Reduction of temperature gradient and carbon contamination in electric current assisted sintering (ECAS/SPS) using a saw-tooth heating schedule

A novel approach for the reduction of temperature gradients and carbon contamination of transparent ceramics prepared via electric current assisted sintering (ECAS) is proposed and successfully demonstrated in the case of transparent spinel ceramics. A so-called saw-tooth heating schedule was applied to attain more homogeneous densification, hereby lowering the level of carbon contamination. An important feature of this saw-tooth heating schedule is that the average heating rate can be retained. The approach is a general one that can be used for other ceramics as well.