Si₃N₄ ceramics brazing with composite soldering materials

Brazing of Si₃N₄ ceramics was achieved with composite soldering materials of Ag-Cu-Ti and TiN.SEM microstructures of joints showed that there was no reaction between TiN particulates and Ag-Cu eutectic matrix,but the interface between them was tight.The TiN particulates are generally homogeneous in the weld which is analogous to metal matrix composites.The diffusion ability of Ti is enhanced due to the strong capillary actions between the TiN particulates and the liquid Ag-Cu matrix alloy,which enables Ti to diffuse sufficiently to the interfaces between the brazing materials and the substrates,on which dense and solid reaction layers are formed.Shear results of joints show that joint strength can be increased obviously in a certain range with composite soldering materials.