In-situ formed SiC whisker strengthening of silicon carbide reticulated porous ceramics based on 3D printed lattices template

The SiC reticulated porous ceramics (RPCs) fabricated via sponge replica method usually showed a poor thermal shock resistance due to their randomly distributed skeleton structure and hollow struts. The present work reports a simple approach to prepare SiC RPCs with 3D lattices structure using the replica of printed resin, followed by pre-heated in coke bed and vacuum infiltration. The increased Si content and flake graphite addition promoted the formation of SiC whiskers network structure on the surface and matrix of SiC preform after pre-heated at 1400 degrees C. As SiC preforms were applied by vacuum infiltration and sintering, the three-layer struts included dense coating, SiC skeleton layer and filling layer were generated. Furthermore, in-situ SiC whiskers eliminated the coating cracks, also optimized the microstructure of the SiC matrix, thereby enhancing the thermal shock resistance and strength of SiC RCPs, whose strength increased from 0.36 MPa to 1.53 MPa, also the residual strength retention rate increased from 0 % to 75.2 % after three cycles of water- quenching.