Direct Tungsten/Copper Bonding for Divertor Application

We carried out a fundamental investigation of uniaxial direct W-to-Cu bonding at relatively low temperatures in ambient air, which would potentially allow for simple preparation and maintenance divertor wall components. W/Cu bonds formed 500◦C with pressure 0.1 MPa, but the mechanical interfacial strength was about 1 significantly lower than state-of-the-art values around 1000◦C vacuum. Higher degree oxidation atomic interdiffusion were observed higher temperature, through x-ray photoelectron spectroscopy. The electrical conductivity across bonded interface, an indicator thermal conductance, measured to be presumably due oxidation.