关键词: 碳化硅复合陶瓷;SiC纳米线;反应烧结

Abstract: The composite of reaction bonded silicon carbide reinforced by SiC nanowires was prepared.At 1550 ℃,the effect of SiC nanowires on the structure and mechanical properties of the materials was studied by X ray diffraction,universal testing machine,density tester and scanning electron microscope (SEM).The results show that compared with the materials without silicon carbide nanowires,the flexural strength and fracture toughness of the composite ceramics with SiC nanowires are improved remarkably,the flexural strength is up to 320 MPa improved by 52％ (12wt％ SiC nanowires),fracture toughness is up to 4.5 MPa · m1/2 increased by 40.6％ (15wt％ SiC nanowire);the SiC nanowires can still maintain the original bamboo-like structure under high sintering temperature;with the addition of SiC nanowires,SiC nanowires pull-outs occure on the fracture surface.Excessive nanowires reduce the density of materials and limited the mechanical properties of the material when the nanowires fraction increases due to the bridging effect of nanowires.The enhancement mechanism of SiCnf/SiC is also discussed.

Key words: silicon carbide composite ceramic;SiC nanowire;reaction bonded