NPE’s unidirectional LAFAD™ sources use a rectangular plasma duct chamber with two rectangular coils installed on opposite sides. Two cathodic arc sources with rectangular or circular (billet) targets are installed in the side walls of the plasma duct chamber, surrounded by rectangular focusing and deflecting coils.
A quasi-flat deflecting magnetic field configuration significantly reduces plasma losses in the direction close to the plasma duct walls, allowing for the dual metal vapor plasma jets to propagate freely along the magnetic field lines to reach remote parts of the deposition chamber. This results in a dramatic increase in output arc current, which can exceed more than 10 amperes for an input current of 300 amperes for two incorporated cathodic arc sources. At the same time, the ionization rate of gaseous plasma components within the magnetized arc plasma column can reach more than 30%. As a result, the deposition rate of LAFAD™ sources has found to be almost the same, or even greater, than that of direct (not-filtered) cathodic arc sources, without sacrificing the benefits of filtration.
LAFAD™ features a unique filtration system, with macroparticles and neutral atoms emitted from the cathode target being captured by baffles installed along plasma duct walls not occupied by vapor plasma sources. This results in practically macro-particle free coatings over large areas, ranging from about 250 mm in width to heights on the order of 300 mm to 3 m or more, with typical target utilization rates for as high as 80-90% for cylindrical (billet) targets, and up to 40% for planar or rotary primary cathodic arc sources with large rectangular or tublar targets.
In addition, the vacuum arc cathode is also a theoretically unlimited electron emitter, thereby providing an efficient source of high-density electron current. In this mode, it facilitates the generation of a uniform, high-density plasma cloud in the coating deposition chamber. This results in a "plasma-immersion" environment, which provides ideal conditions for plasma ion etching, ion nitriding, low energy ion implantation, plasma-assisted chemical vapor deposition, and multilayer filtered arc PVD coatings, all in a single vacuum cycle.
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