Microstructure and mechanical properties of PDA-CNTs@f-Ti₃C₂-reinforced SiC matrix composites

Poor fracture toughness is a major limitation of SiC ceramics, which greatly affects their application range. Herein, a novel strategy is proposed to enhance the fracture toughness of SiC ceramics by cross-linking carbon nanotubes (CNTs) coated with polydopamine (PDA) to Ti₃C₂ modified with 3-glycidyloxypropyltrime-thoxysilane (KH560) (PDA-CNTs@f-Ti₃C₂). Then, PDA-CNTs@f-Ti₃C₂ was added to SiC powder to prepare the final composite. The influence of PDA-CNTs@f-Ti₃C₂ addition on the microstructure and mechanical properties of the SiC composite is discussed. The results showed that, compared with CNTs and Ti₃C₂, the PDA-CNTs@f-Ti₃C₂ composites exhibited better dispersibility in water. The flexural strength was significantly enhanced (~89%) in the SiC composite containing 3 wt% PDA-CNTs@f-Ti₃C₂, from 228.99 MPa to 433.55 MPa. The fracture toughness of the SiC composite containing 3 wt% PDA-CNTs@f-Ti₃C₂ improved by 62%, from 3.97 MPa/m^1/2 to 6.44 MPa/m^1/2.