Properties and fracture processes of Si_3N_4/Si_3N_4 joint brazed using Cu-Zn-Ti filler alloy

摘要

Si_3N_4 ceramic was jointed to itself using a filler alloy of Cu-Zn-Ti at 1123-1323 K for 0.3-2.7 ks. Ti content in the Cu-Zn-Ti filler alloy was varied from 5 to 20 at. -percent. The effect of brazing parameters, such as brazing temperature, holding time and Ti content, on the mechanical properties and facture processes of the Si_3N_4/Si_3N_4 joint were investigated. The results indicated that the increased brazing temperature, holding time and Ti content increase the thickness of the inter/octal reaction zone in the Si_3N_4/filler alloy, and. the size and amount of the reaction phases in the filler alloy. Their increases lead to increasing shear strength of the joint. The fracture behaviour of the Si_3N_4/Si_3N_4 joint greatly depends on the microstructure of the joint. A suitable thick reaction zone with reaction phases yields the high strength of the Si_3N_4/Si_3N_4 joint.