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

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 disintegration and interlocking of the SiC grains. The final porosity of the Si/SiC-parts is below 1%. Their mechanical and thermal properties (as density, bending strength, Young's modulus, thermal conductivity, thermal expansion coeff i-cient) 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 example, can be generated.