Effect of holding time on the self-joining of silicon nitride

Reliable Si3N4/Si3N4 joints were obtained using CuPdTi as filler alloy. The effect of holding time on interfacial microstructure and bonding strength of the joints was investigated. All the joints consist of continuous reaction layer (fine-grain TiN), discontinuous reaction layer (coarse-grain TiN), Cu-based solid solution and reaction products. Prolonged exposure to the elevated temperature causes the thickness of the discontinuous reaction layer to increase, due to the coarsening of TiN grains. And the amount of PdSi phase increases instead of TiSi phase. With the increase of holding time, the bonding strength of the joints decreases. The formation of a reaction layer with a suitable thickness promotes the improvement of bonding strength of joints.