The special feature of the GPS process is a sequence of dewaxing at low pressure, sintering at normal pressure and -after a status is reached with only closed pores being present in the material - sintering at a high pressure, which results in a further densification and faster elimination of the remaining pores. Therefore materials produced in the GPS technology show in general mechanical properties (hardness, strength, Weibull-modulus, fracture toughness) which are superior to those of pore-free materials produced by the conventional sintering method.
The devices are particularly suitable for sintering such types of ceramics or metals, which tend to decomposition at elevated temperatures or which do not sinter to high densities in standard sintering operations. This process has not the limitations with respect to the shape of the manufactured parts as in hot pressing and it is also an advantageous alternative to the more costly HIP-process.
The laboratory-type GPS plant is optionally equipped with an integrated dilatometer, which monitors shrinkage and shrinkage rate during the course of the sintering process. The obtained measured data are used for the process control.
Available volume: 1 dm³ to 500 dm³ at 2200°C / 10 MPa (N2 or Ar atmosphere)
GPS plants are used for the production of:
Sintered silicon nitride and sialon with excellent mechanical properties (e.g. cutting tools, turbocharger rotors, engine components)
Silicon carbide (mechanically heavy strained parts in corrosive environments etc.)
Super alloys (mechanically strained parts in high-temperature applications)
Hard metals, especially cemented carbides with low content of Cobalt and for high-quality grades with optimum mechanical properties.
Composite materials in general
A very promising application of this technique is the production of serial parts made of SSN for the automobile industry.