Review on high-pressure spark plasma sintering and simulation of the impact of die/punch material combinations on the sample temperature homogeneity

This paper provides a thorough review on high-pressure spark plasma sintering (HP-SPS) experiments conducted to date, with a focus on different tooling materials and their impact on microstructural, mechanical and optical properties of the resulting materials. Any SPS experiment conducted with a pressure over 200 MPa was considered as “high-pressure”. This review was supported by a comprehensive finite-element modelling study of the temperature distribution in the sample and tool set-up as a function of the used geometries, tooling material combinations, temperature window and sample material properties. The effect of the electrical and thermal conductivities of the tool and sample material on the temperature gradients in some specific sample-tool material combinations was elucidated. Electrically and thermally conductive samples in combination with SiC tools showed the lowest temperature gradients during processing, whereas electrical insulators in combination with high pressure WC, steel or TZM tools with an inner graphite die showed the smallest temperature gradients over the sample.