Plasma arc apparatus for applying coatings by means of a consumable cathode

A plasma arc apparatus for applying coatings comprising:

• (a) a working anode chamber of a non-magnetic metal, made in the form of a pipe of a uniform cross-section having a predetermined axial length and intended for work to be disposed therein and to be subjected to a plasma spraying process;
• (b) an annular consumable cathode having a central opening for work to be installed therewithin in a working position within said working anode chamber and having a cross-sectional configuration, which substantially coincides with the cross-sectional configuration of said pipe which forms said chamber, said cathode being disposed within the latter in coaxial relationship therewith and having a lateral evaporation surface that faces said anode chamber and is of an axial length less than the axial length of the anode chamber;
• (c) a starting electrode serving to start an arc discharge;
• (d) a direct current source for feeding electrical power to form an arc between said anode and cathode, said direct current source being connected with said anode and cathode;
• (e) a pulsed current source for starting the arc, said pulsed current source being initially connected with said cathode and the starting electrode;
• (f) a magnetic system for diverting charged particles of plasma produced in said working anode chamber from the surface of the anode chamber towards the working being treated, said system being mounted on the outer side of said pipe forming said working anode chamber.