Selecting Technological Sandwich for Vacuum Diffusion Welding of Compact Cutter

In order to solve the key problem in the vacuum diffusion welding technology bonding compact cutter used for polycrystalline diamond compact bits and hard alloy, a test for selecting technological sandwich is conducted. The result shows that the shear strength of the bonding seam by using the cold-rolled Ni foil as sandwich is higher than the shear strength by using the Cu foil under the same conditions;the relationship between the thickness of sandwich Ni and the shear strength of the bonding seam is obtained under the testing bonding parameters; with the help of the electron microscopy, the diffusion process of elements on the interface is investigated,the result shows that when using 45 μm cold-rolled Ni foil as sandwich and if only the diffusion distance of the element Ni exceeds 11 μm, high quality bonding seam that the shear strength equals 485 MPa can be obtained.