Temperature-dependent thermal properties of spark plasma sintered alumina

In this work, we report temperature-dependent thermal properties of alumina powder and bulk alumina consolidated by spark plasma sintering method. The properties were measured between room temperature and 250 °C using a thermal constants analyzer. Alumina powder had very low thermal properties due to the presence of large pores and absence of bonding between its particles. Fully dense alumina with a relative density of 99.6 % was obtained at a sintering temperature of 1400 °C and a holding time of 10 min. Thermal properties were found to mainly dependent on density. Thermal conductivity, thermal diffusivity, and specific heat of the fully dense alumina were 34.44 W/mK, 7.62 mm²s^-1, and 1.22 J/gK, respectively, at room temperature. Thermal conductivity and thermal diffusivity decreased while specific heat increased with the increase in temperature from room temperature to 250 °C.