Laser additive manufacturing and homogeneous densification of complicated shape SiC ceramic parts

To improve the density of SiC ceramic components with complicated shape built by laser sintering (LS), cold isostatic pressing (CIP) and reaction sintering (RS) were incorporated into the process. In the process of LS/CIP/RS, Phenol formaldehyde resin (PF)-SiC composite powder was prepared by mechanical mixing and cold coating methods, with an optimized content of PF at 18 wt%. For the purpose of obtaining improved density of the sintered body after final reaction sintering, carbon black was added into the initial mixed powder. The material preparation, LS forming and densification steps were optimized throughout the whole fabrication process. The final sintered SiC bodies with the bending strength of 292 similar to 348 MPa and the density of 2.94-2.98 g cm(-3) were prepared using the PF coated SiC-C composite powder and the LS / CIP / RS process. The study further showed a positive and practical approach to fabricate SiC ceramic parts with complicated shape using additive manufacturing technology.