Reaction Sintering of Carbon Fiber Reinforced Silicon Carbide Composite by Gel-Casting Method with Water Soluble Epoxy Resin as Gel Former

Abstract

Reaction-bonding sintering silicon carbide (RB-SiC) toughened by 10vol% short carbon fibers were produced by Gel-casting method using water soluble epoxy as gel former and then reaction sintering at 1750°C under vacuum atmosphere for 2 h . SEM showed that short carbon fibers could disperse uniformly in the preforms and sintered carbon fiber reinforced silicon carbide composites (Cf/SiC). The mechanical test results showed that the strength decrease from 286 MPa for RB-SiC to 231 MPa for Cf/SiC, however, the fracture toughness of Cf/SiC increased from 3.65 MPa m1/2 to 5.28 MPa m1/2 compared with RB-SiC. The strength decrease of the Cf/SiC should be ascribed to the chemical reaction between the addition of short fibers and matrix, and the increase of the fracture toughness could be attributed to fiber debonding, fiber pull-out and crack deflection .