Direct Hot Pressing (SPS/FAST)
Direct hot pressing is from its basics a well approved and known technology, but the past decades were dominated by devices operated at temperatures of max. 1,400° C and mainly used for the consolidation of wear resistant inserts for cutting wheels, drill bits or in grinding discs.
SPS (Spark Plasma Sintering) or FAST (Field Assisted Sintering) machines are other commercial names for this technology, typically further developed for hot pressing temperatures up to 2,400° C and even above. The big advantage are the rapid heating rates and the short processing cycles. This does not only lead to cost effective production, but also to interesting effects studied in fine grained microstructure and corresponding properties of the consolidated materials.
Therefore this technique can be effectively used for the consolidation of materials usually difficult to sinter. The technology is especially of advantage for high temperature materials especially if fully dense or fine grained microstructures in combination with an excellent performance are required.
Direct hot pressing is characterised by a high heating/cooling rate (up to 400 K/min) and therefore offers a very attractive process for economic fabrication of high performance materials.
Typical Process Parameters:
Heating rate: 100 - 200 K/min (max 400 K/min)
Cooling rate: 100 - 200 K/min
Max. temperature: 2,400° C
Mech. pressure: 30MPa
Atmospheres: Vac, Ar, N2, forming gas
Sample max. 300mmx300mm
Typical cycle: < 1 hrs