Spark plasma sintering (SPS), also known as field assisted sintering technique (FAST)[1] or pulsed electric current sintering (PECS), is a sintering technique.
The main characteristic of SPS is that the pulsed DC current directly passes through the graphite die, as well as the powder compact, in case of conductive samples. Therefore, the heat is generated internally, in contrast to the conventional hot pressing, where the heat is provided by external heating elements. This facilitates a very high heating or cooling rate (up to 1000 K/min), hence the sintering process generally is very fast (within a few minutes). The general speed of the process ensures it has the potential of densifying powders with nanosize or nanostructure while avoiding coarsening which accompanies standard densification routes. Whether plasma is generated has not been confirmed yet, especially when non-conductive ceramic powders are compacted. It has, however, been experimentally verified that densification is enhanced by the use of a current or field.