Combustion synthesis of MoSi2 based composite and selective laser sintering thereof

Additive manufacturing is gaining increasing attention as it provides cost-effective and waste-less production of materials with multi-axis geometries. Selective laser sintering of ceramics is very challenging in terms of poor sinterability caused by low thermal shock resistance and insufficient electron conductivity blocking absorption of laser beam energy.Here, we present a novel strategy for manufacturing dense, hierarchically structured ceramics, particularly, MoSi₂-based composites by selective laser sintering. MoSi₂-Si composite powders were prepared by combustion synthesis technique, where the ceramic grains were covered with different amount of Si. MoSi₂-Si powder was consolidated by selective laser sintering reaching 92% of density. The hardness of the manufactured samples varied with the amount of Si and applied laser current from 7.7–11.4?GPa. The maximum value of the compressive strength was determined to be 636?MPa. The manufactured MoSi₂-Si was subjected to nitridation, which resulted in the growth of Si₃N₄ fibres on the surface and pores of the samples.