The Strength of Vacuum-Free Diffusion Bonding Joints of Ni-Bi Alloys and ZrO2 Ceramic

Abstract

Ni-Bi alloys were selected to bond to ZrO2 ceramic by diffusion bonding at atmosphere for researching their bondability. The Ni-Bi alloys were Ni-xmass%Bi (x=0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) and ZrO2 ceramic was Z201N. The bonding was carried out at 973 K, 1037 K and 1173 K for 3.6 ks, 5.4 ks, 7.2 ks, 9.0 ks and10.8 ks under the pressure of 2 MPa, 4 MPa, 6 MPa, 8 MPa, 10 MPa and 12 MPa. The bonding strength was examined by the shear fracture test from room temperature to high temperature. The results indicate that pure nickel could be bonded to ZrO2. Adding bismuth into nickel alloy could obviously improved shear strength at room temperature. The optimum content of bismuth was 2%. The shear strength of vacuum-free diffusion bonding joint was higher than that of vacuum diffusion bonding joint. ZrO2/Ni-2Bi joint was bonded at 1173 K for 7.2 ks under 8 MPa, which shear strength was up to 22 MPa until the test temperature of 873 K.