Effect of surface state of SiC fibers on their interfacial properties

SiC/SiC composites fabricated using the MI process have been successfully utilized in aero engines, demonstrating the reliability of this method. The MI process involves a resin-wetting step that influences the bond strength between the fiber or interfacial layer and the resin matrix, impacting the performance of the resulting composite materials. This paper analyzes the surface state, tensile strength, and interfacial properties of various SiC fibers (sized, desized, and with a BN interface layer) using multiple surface interface testing methods. The findings indicate that sizing treatment enhances the surface energy of SiC fibers, thereby improving the interfacial bonding strength with the resin. Both the single-fiber fracture test(SFFT) and microdroplet debonding test(MDT) can reflect the trends in interfacial strength, with MDT experiments revealing an interfacial shear strength of 85.1 MPa between fiber and resin.