Microstructure and mechanical properties of ZrB2–SiC ultrahigh temperature ceramic composite joint using TiZrNiCu filler metal

ZrB2–SiC ceramic composite was brazed by using TiZrNiCu active filler metal. The microstructure and interfacial phenomena of the joints were analysed by means of SEM, energy dispersive X-ray spectroscopy and X-ray diffraction. The joining effect was evaluated by shear strength. The results showed that the reaction products of the ZrB2–SiC ceramic composite joint were TiC, ZrC, Ti5Si3, Zr2Si, Zr(s,s) and (Ti, Zr)2 (Ni, Cu), and the microstructure was separately ZrB2–SiC/Zr(s,s)/Ti5Si3+Zr2Si+TiC+ZrC+(Ti,Zr)2(Ni,Cu)/Zr(s,s)/ZrB2–SiC. A conceptual interface evolution model was established to explain the interface evolution mechanism. The maximum shear strength of the brazed joints was 143·5 MPa at the brazing temperature T of 920°C and the holding time t of 10 min.