Biography
Biography: Eugenio Zapata-Solvas
Abstract
Electric current assisted sintering (ECAS) techniques, such as electrical discharge sintering (EDS) or resistive sintering (RS), have been intensively investigated for longer than 50 years. In this work, a novel system including an electrically isolated graphite die for Spark Plasma Sintering (SPS) is described, which allows the sintering of any refractory ceramic material in less than 1 minute starting from room temperature with heating rates higher than 2000ºC/min and an energy consumption up to 100 times lower than with SPS. The system alternates or combines direct resistive sintering (DRS) and indirect resistive sintering (IRS). Electrical isolation of the die has been achieved through the insertion of a film made of alumina fibers between the graphite die and the graphite punches, which are protected from the alumina fibers film by a graphite foil. This system localized the electric current directly through the sample (conductive materials) as in DRS and EDS, or through the thin graphite foil (non-conductive materials) as in IRS or RS and is the first system capable of being used under EDS or RS conditions independently, combining current concentration/localization phenomena. In addition, geometry elements of the graphite mold used for SPS, such as graphite mold wall thickness or graphite punch diameter, play an important role in the electric field magnitude during sintering. Furthermore, electric field for this novel geometry will be analyzed as well as tailorability of electric field in order to intensify the value of the electric field towards induced flash sintering in a SPS furnace.