Characterization of Capillary Discharge Ejecta Onto Metal Substrates

An electrothermal (ET) capillary arc discharge is an effective source of high-density plasmas which can be used to evaluate high heat flux plasma impact on materials 1 . In this work, W and Mo samples were exposed to plasmas with densities between 10 19 and 10 23 m -3 , temperatures between 0.1 and 1 eV, and a mixed material composition from W/polycarbonate and Mo/polycarbonate liners. These plasma-impacted materials have been characterized using EDS, XPS, FIB, nanoindentation and refractometry in order to determine microstructure of the surface and bulk material, surface composition and sample wear behavior (strain behavior, surface roughness). The surface was confirmed to be primarily composed of metal-carbides on self-similar substrates, with trace amounts of other metals including copper from the cathode. Deposited materials showed good adhesion, with textured amorphous surfaces and grain sizes of about 50 nm. The penetration depth of ablated material and mechanical properties of the samples will be reported in detail, with early results suggesting nucleation is the primary mechanism behind surface structural organization during plasma deposition.