Microstructures of diffusion bonded SiC ceramics using Ti and Mo interlayers

Abstract SiC plates were diffusion bonded using metallic interlayers of Ti and Mo foils. For the joining, a uniaxial pressure of ∼7 MPa was applied at 1400 °C for 1 h in a vacuum. The interfacial microstructures along with their atomic compositions of the SiC/SiC joints were analyzed. For the Ti interlayer, Ti was converted into a Ti 3 SiC 2 phase owing to the diffusion of silicon and carbon from the SiC part. A crystallographic orientation relationship was found between the SiC and Ti 3 SiC 2 grains. At the middle of the Ti interlayer, a TiSi 2 phase also existed, forming a dual-phase region. For the Mo interlayer, the diffusion of silicon into Mo induced the formation of the Mo 5 Si 3 C phase at the SiC/Mo interface. An unreacted metallic phase was still observed in the middle of the Mo insert. The shear strengths of the joints were 67 MPa and 76 MPa for the Ti and Mo interlayers, respectively.