Effect of additional elements in Ag-Cu based filler metal on brazing of aluminum nitride to metals.

Abstract

Brazing of aluminum nitride to copper was performed using Ag-Cu-Ti, Ag-Cu-Ti-Co and Ag-Cu-Ti-Nb brazing filler metals in an argon atmosphere. The reaction layer formed at the interface between AlN and braze layer in AlN-Cu joints was found to increase by increasing brazing time for all brazing filler metals used. In the case of the fillen metal Ag-Cu-Ti-Nb, a thinner reaction layer was formed in comparison with the cases of using other filler metals. Form an EPMA analysis, it was found that not only Ti, but also Nb were concentrated in this thin reaction layer. From XRD analysis, it was found that TiN lattice was distorted by Nb addition. Shear strengths were measured for AlN-W joints at room temperature. The joint brazed at 1 173 K for 0.3 ks using Ag-Cu-Ti filler metal showed a strength of 118 MPa. In the case of using Ag-Cu-Ti-Co filler metal, almost the same shear strength, 116 MPa, was obtained after brazing at 1 173 K for 0.6 ks. The joints brazed at 1 173 K for 0.3 ks using Ag-Cu-Ti-Nb filler metal exhibited the maximum shear strength 147 MPa. The shear strength of the joints was discussed in relation to the thickness of the reaction layer.