Sn/Ni-8.0 at.%V (Ni-7.0 wt%V) couples are prepared and the interfacial reactions at 210 and 250°C are examined. In the early stage of reaction at 250°C, a T phase is formed as a result of fast diffusion of Sn into the Ni-8.0 at.%V substrate. With a longer reaction, the outer region of the T phase transforms to a Ni-depletion layer, which has not been observed previously. Both the T phase and the Ni-depletion layer are analyzed using transmission electronic microscopy. This newly found Ni-depletion layer is composed of Sn and nanosize "VSn2(V2Sn3)" particulates. The solid/solid reaction paths in the Sn/Ni-8.0 at.%V couples evolve from Sn/T/Ni-V, Sn/Ni3Sn4/T/Ni-V to Sn/Ni3Sn 4/VSn2(V2Sn3). During the liquid/solid reactions, the paths are liquid/T/Ni-V, liquid/liquid + Ni3Sn4/T/Ni-V, liquid/liquid + Ni3Sn4/liquid + VSn2(V2Sn 3)/T/Ni-V, and liquid/liquid + Ni3Sn4/liquid + VSn2(V 2Sn3).