Coupling SHS and SPS Processes

Abstract

The consolidation of refractory ceramic powders at relatively milder conditions with respect to conventional methods represents an important target to achieve. Based on results recently reported in the literature, it is possible to state that the combination of the Self-propagating High-temperature Synthesis (SHS) with the Spark Plasma Sintering (SPS) technologies provides a useful contribution in this direction. Specifically, the two-steps processing route consisting in the synthesis of the ceramic powders by SHS and their subsequent densification by SPS is successfully utilized to obtain various dense MB2-based materials (M= Zr, Hf, Ta). In this regard, an important role is played by the SHS process, particularly for the synthesis of composite powders. Indeed, stronger interfaces are established among the different phases formed in-situ, so that diffusion phenomena are promoted during SPS. Additional benefits are produced by the use of the latter technology, due to the direct passage of the electric current through the powders undergoing sintering and the die containing them.