Transformation of axial vacuum-arc plasma flows into radial streams and their use in coating deposition

Radial filtered plasma flow formation in the annular gap between two oppositely directed rectilinear vacuum-arc erosion-plasma sources with magnetic focusing has been investigated. In both the opposing and aiding magnetic field configurations in the gap, the ion how density first increased to a certain maximum value (/spl sim/4 mA/cm/sup 2/ for Ti plasma) and then decreased with magnetic field strength, For this optimum condition the plasma losses during transformation of the axial flow into the radial flow were less than 20% in high vacuum. A uniform deposition rate of /spl sim/5 /spl mu/m/h (for droplet-free Al and Ti coatings) was achieved over the annular substrate surface of 1300 cm/sup 2/. (In case of conventional curvilinear filters this area is generally 10-20 cm/sup 2/).