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Prototyping of complex-shaped parts and tools of Si/SiC-ceramics by selective laser sintering

Herstellung kompliziert geformter Prototypen von Bauteilen und Werkzeugen aus Si/SiC-Keramiken mittels selektivem Laser-Sintern
: Löschau, W.; Lenk, R.; Scharek, S.; Teichgräber, M.

CIMTEC '98. Proceedings
Florenz, 1998
CIMTEC, World Ceramics Congress & Forum on New Materials <1998, Florenz>
Conference Paper
Fraunhofer IWS ()
Bauteil; infiltration; laser; Rapid Prototyping; selektives laser-Sintern; Si/SiC-Keramik; Strukturkeramik; Werkzeuge laser

Also in the case of structural ceramics, technical prototypes of parts and tools are to consist of materials and to show properties close to those of the series products. Results are presented on generating very complex parts with undercuts and internal voids by layer-wise selective laser sintering of pure SiC-powder without additives. The sintered parts are then infiltrated with Si in vacuum without distortions. The sintering process is brought about by the transient formation of different Si-base phases and by partial crushing and dissolution of the SiC grains. The final porosity of the Si/SiC-parts is below 1 per cent. Their mechanical and thermal properties (as density, bending strength, Young's modulus, thermal conductivity, thermal expansion coefficient) can be controlled via Si-content. They are slightly below those of conventional Si/SiC-ceramics.It is expected that by means of this technique, rigid light-weight mirrors and wear and temperature resistant dies and tools, for exa mple, can be generated.