Effects of carbon content on microstructure and mechanical properties of SiC ceramics fabricated by SLS/RMI composite process

Abstract Selective Laser Sinering (SLS) and Reactive Melting Infiltration (RMI) were combined to fabricate complicated SiC ceramics with high performance in the research. The influence of carbon content on green parts’ mechanical properties was studied. Then, the effect of carbon density on the microstructure of SiC was studied. The results showed that the density of sintered body increased first and then decreased with the increase of carbon black content. Due to the increase of carbon density, the siliconizing property of carbonated preforms is also improved by impregnating asphalt. When the carbon density was 0.6612 g/cm3, sintered density reached 2.899 g/cm3. But the flexural strength reached peak value of 190.19 ± 1.89 MPa as the carbon density decreased to 0.5542 g/cm3. Therefore, this research lays a foundation for laser sintering to fabricate high performance and complex structure SiC ceramics by regulating carbon content.