Microstructure and Mechanical Properties of the Joint between Si3N4 and Mo Brazed by Near‐Eutectic Ag–Cu–In–Ti Filler Alloy

The joining of Si3N4 and Mo using Ag–Cu–In–Ti active filler alloy with the brazing temperature ranging from 720 to 860 °C for 10 min is investigated in this article. The correlation between the joint strength and the microstructures of the brazed joints is discussed. In the results, it is shown that the activity of Ti is different at different temperatures, and thus the degree of diffusion of Ti to the interface is different. The activity of Ti gradually increases as the brazing temperature increases, and more Ti atoms diffuse into both sides of the base materials, resulting in a progressively thicker TiN + Ti5Si3 reaction layer on the Si3N4 ceramic side. Between 720 and 860 °C, the shear strength of the joint first increases and then decreases with brazing temperature. The maximum shear strength (223 MPa) is obtained at 830 °C.