Electrothermal Simulation of the Production of Alumina by Spark Plasma Sintering

Abstract

Although the spark plasma sintering (SPS) method is a very advantageous technque in many aspects, the inability to clearly read the temperature formed on the material during sintering and heterogeneous temperature distributions are the biggest problems of this process. Therefore, it is a common situation that samples taken from different regions of the produced material have different densities and mechanical properties. In this study, the temperature distributions, current density and joule heating effect of the entire setup consisting of the alumina (Al2O3) sample to be sintered, inconel electrodes, graphite dies, punches and spacers, as well as the critical regions in this setup, are modeled by using finite element software. According to the results, the temperature is maximum at the centre of the Al2O3 sample and the temperature gradient along its radius is 22.4°C. The temperature difference between the inner wall of the hole which is opened in the graphite mold to measure the sintering temperature and the centre of the Al2O3 sample is around 40°C. In addition, during the SPS process, Al2O3 is not heated directly by the joule effect and the temperature gradient in the sample occurs due to mold surface radiation.