Microstructure and mechanical properties of multilayer SiC nanofiber paper-reinforced SiC composites by the NITE method

In this work, stacked SiC fibers paper-reinforced SiC ceramic matrix composites (SiC nf /SiC CMCs) were prepared by nanoimpregnation and transient eutectic (NITE) process using ultra-long single-crystal SiC nanofibers. The effect of the SiC nf surface modification via boron nitride (BN) interphase deposition as well as the sintering additive (Al 2 O 3 –Y 2 O 3 ) content on the density, microstructure, and mechanical properties of SiC nf /SiC CMCs has been investigated systematically. The results revealed that the laminated SiC nf /SiC CMCs feature a significant saw-tooth-like curve on the load–displacement test, which indicates that the obtained laminated structure with the weak interlayer binding owning to the BN coating treatment possesses significant toughening to the SiC ceramics. Specifically, the SiC nf /SiC CMCs with the sintering additive content of 12 wt% revealed a fracture toughness of over 10 MPa m 1/2 after 60 min of BN interface deposition, which is 104.31% higher than that of the composites prepared without BN coating.