Transient liquid phase process in Ni-B joining

Abstract

With the use of the diffusion bonding system of Ni/B/Ni, the liquid layer at the Ni/B interface was studied. In the previous report we suggested that the intermediate layer of pure B which has a high diffusivity in Ni and a high melting temperature can reduce the bonding time of the TLP (Transient Liquid Phase) process. In the present study the Ni/B/Ni specimen was bonded at temperatures of 1433-1473 K in vacuum. As a result, a liquid metal in the bonding zone was formed by mixing the diffused atoms of the intermediate layer of solid state with the base metal. For this procedure incubation time of 25 s was required. The initial width and the maximum width of the liquid layer were 3.5 and 9 times, respectively, wider than the thickness of the intermediate layer. With a similar bonding procedure, pure carbon (C) can be used also as an intermediate layer.