Generation of Noble and Refractory Metals Plasma Jets by Electrothermal Discharge for Surface Deposition Applications

Arc-dominated capillary discharges generate high-density plasmas from the ablation of the material of the inner lining sleeve, where ablation is determined by the radiant energy transport in such electrothermal (ET) plasma devices. Properties of sleeve material are an important factor on the generated plasma in ET devices. The 1-D time-dependent NC State University ET plasma code ETFLOW provides simulation of the capillary discharge and predicts the plasma parameters along the capillary axis. Of interest are the plasma parameters at the exit of the capillary which include temperature, pressure, velocity, heat flux and total ablated mass ejected from the source. The experimental discharge current was used in the code, and the plasma parameters at the source exit were calculated. Six materials were tested, namely, titanium, chromium, copper, silver, platinum, and gold. The code results show that the plasma temperature is between 2.4 and 2.57 eV for all tested materials. The lower heat of sublimation of gold and silver leads to increase the total ablated mass, density, electrical conductivity, and the exit pressure combined with reduction of the plasma bulk velocity. The gold has the highest ablated mass while titanium has the lowest values. The total ablated mass of copper material is about 168 mg, which is in a good agreement with previous experimental results.