About the technology
Spark Plasma Sintering (SPS) or Field Assisted Sintering Technology (FAST) is a sintering technique utilizing uniaxial force and a pulsed (on-off) direct electrical current (DC) or alternating current (AC) under low atmospheric pressure or inert gas to perform high speed consolidation of powders. This direct way of heating allows very high heating and cooling rates, enhancing densification compared to grain growth promoting diffusion mechanisms, allowing to maintain the intrinsic properties of e.g. nanopowders in their fully dense products.
It is regarded as a rapid sintering method in which the heating power is not only distributed homogeneously over the volume of the powder compact in a macroscopic scale, but moreover dissipated exactly at those locations in the microscopic scale where energy is required for the sintering process, namely at the contact points of the powder particles. This fact results in a favourable sintering behaviour with less grain growth and suppressed powder decomposition. Depending on the type of the powder, additional advantageous effects at the contact points are assumed by a couple of authors.