Selection and Testing of High Current Contact Materials for Tokamak Devices

Materials for potential use in tokamak first wall high current connectors were selected and tested under conditions that might be encountered in tokamak devices. Disk-shaped specimens of promising metal mixtures were subjected to current densities approaching 23 kA/cm² (150 kA/in²) in 8 ms pulses, closing pressures ranging from .07 to 2.1 MPa (10 to 300 psi), and a vacuum of 1.3 × 10⁻¹ Pa (10⁻³ Torr). Contact welding occurred at moderate to low pressure and moderate currents. The resulting welds were very weak, failing at 18–31 N (4–7 lb) in shear.