Densification of Binder Jet-printed Silicon Carbide Ceramics by Cyclic Post-Impregnation Without Cyclic Pyrolysis

The binder-jet forming technique, combined with a simplified phenolic resin impregnation process, was used to prepare high-performance silicon carbide ceramics. The carbon enhancement process was explored using a pre-mixed phenolic resin and cyclic impregnation, while cyclic pyrolysis was replaced by a baking process at 120ºC. The effects of different printing powders and impregnation cycles on the molding accuracy, density, residual silicon content, thermal conductivity, and mechanical properties of the samples were systematically investigated. The results showed that the printed density was 1.53 g/cm 3 , with a carbon density of 0.55 g/cm 3 . The phenolic resin impregnation treatment effectively filled the internal pores, further increasing the green body density to 1.71 g/cm 3 and the carbon density to 0.71 g/cm 3 . The density of the SiC ceramics obtained by the silicone infiltration process reached 2.93 g/cm 3 , the thermal conductivity was 151.8 W/(m · K), and the flexural strength was 241 ± 14.08 MPa. Overall, cyclic post-impregnation of phenolic resin without the pyrolysis process can effectively enhance the density and properties of binder-injected SiC ceramics.