Processing and thermal properties of SrTiO3/Ti3AlC2 ceramic nanocomposites

Modulating the thermal conductivity has been a pragmatic approach for the development of high-performance thermoelectric material and thereby a step forward towards commercialization. Despite some efforts, the reduction in thermal conductivity of SrTiO3 ceramic has not been fully realized. In this work, Ti3AlC2 in 3, and 7 vol% were uniformly incorporated in SrTiO3 through nanostructured powder processing. The pristine SrTiO3 and composites powders were consolidated by the spark plasma sintering at 1200 degrees C under uniaxial pressure of 50 MPa. Thermal properties of the bulk samples were evaluated from room temperature to 750 K through laser flash analysis. The thermal conductivity of SrTiO3 based composites decreases substantially with the addition of nanostructured Ti3AlC2 from the pristine SrTiO3 bulk sample. The reduction in thermal conductivity of 7 vol% composites is more than 30% at room temperature and even higher at elevated temperatures from the SrTiO3. The interface thermal resistance was estimated which indicates a dominant role in diminishing the thermal conductivities of the composites. The results suggest that the addition of Ti3AlC2 as a second phase and nano structuring through ball milling has significantly altered the phonon scattering mechanisms through multiple factors and thereby contributed to reducing effective thermal conductivities of the composites. This, work provide a scalable and economical route for the development of high-performance thermoelectric material.