Spark plasma sintering (SPS), alternatively pulsed electric current sintering (PECS), is a sintering technique utilising uniaxial force and a pulsed direct electrical current under low atmospheric pressure to manage high speed consolidation of the powder. This way of direct heating enables application of a high heating rate, improving densification over grain growth, it also maintains the intrinsic properties in fully dense products of nanopowders and facilitates diffusion mechanisms.
SPS is considered a rapid sintering method in which the heating power targets the contact points of the powder particles. This leads to a variety of appreciated sintering properties as less grain growth and suppressed powder decomposition. Depending on the powder, different advantageous effects at the contact points will arise.
SPS offers many advantages over conventional systems using hot press (HP), hot isostatic pressing (HIP) or atmospheric furnaces. In comparison to HP, HIP and atmospheric furnaces SPS offers ease of operations, precise control of sintering energy, high sintering speed, reproducibility, safety and reliability.
SPS is characterized by utilization of electric current which leads to rapid and efficient heating. Heating rate during SPS process depends on various factors, the construction of the sample ensemble, thermal and electric properties and the electric power provider. This in facts enable SPS to reach heating rates at astonishing 1000°C/min.
The SPS process is based on the electrical spark discharge phenomenon, a high energy, low voltage spark pulse current momentarily generates spark plasma in specific areas. SPS process temperatures vary from low to high temperatures (over 2500℃) and are generally lower than during conventional sintering. SPS enables a fast and steady process which allows vaporisation, melting and sintering completed in between 5-20 minutes.
Our supplier is involved in a public/private agreement with CINN, which allows us to exploit customized SPS. The customized SPS-station is equipped with special instruments which prevent temperature gradients in large sized components and facilitate inductive heating of materials that in other circumstances have a dielectric behaviour at room temperature.