The Improvement of Bonding Strength of W/Cu Joints via Nano-Treatment of the W Surface

Abstract

W/Cu joining is key for the fabrication of plasma-facing compounds of fusion reactors. In this work, W and Cu are joined through three steps: (1) hydrothermal treatment and reduction annealing (i.e., nano-treatment), (2) Cu plating and annealing in a pure H2 atmosphere, and (3) W/Cu bonding at 980 °C for 3 h. After nano-treatment, nanosheets structure can be found on the W substrate surface. The tensile strength of the W/Cu joint prepared via nano-treatment reaches as high as approximately 93 MPa, which increases by about 60% compared with the one without nano-treatment. The microhardness curves exhibited continuous variations along the W/Cu interface. The TEM images show that the W/Cu interface is compact without any cracks or voids. This work may also be applied for enhancing bonding strength in other immiscible materials.