Calculation of thermal fields in a graphite mold during spark-plasma sintering of non-conductive materials

Abstract

The research provides modeling of spark-plasma sintering process of aluminum oxide, specifically the distribution of temperature fields over the sample volume and mold at various stages of heating. Calculation was based on the experimental data on the measurement of temperature on the surface of the mold, inside the mold cavity and in its various internal parts including punches (diameter of 15 mm), in the absence of insulation felt. Experiments established that the main source of heat emission at temperatures less than 1300°C to 1400 °C is contact resistance at the borders of the punches and the matrix molds. Then heat emission zone moves towards the punches. Based on the received data, the temperature and electric parameters were selected for the materials used for the press mold, providing a good agreement between the observed and calculated distribution patterns at different temperatures. Obtained parameters were used in calculations of temperature fields in the press molds with insulation felt and for the press molds with diameter of 15 mm and 10 mm for the production of tablets as well as glazing beads.