Abstract: Pressureless-sintered (PLS) SiC was bonded to SiC through Nb foil interlayer by vaccum diffusion method.At the initial stage of reaction,a hexagonal Nb₂C phase and a hexagonal Nb₅Si₃Cx phase occured on the Nb side and on the SiC side,respectively.With the increase in bonding time,a cubic NbC phase and a hexagonal NbSi₂ phase appeared at the interface.The experimental results showed that shear strengrh of the joint,which was bonded at 1790 K for 36ks,was up to 187 MPa at room temperature and more than 150 MPa at the test tempeature of 973 K.