INNER SURFACE VACUUM TREATMENT METHOD Russian patent published in 1995 - IPC

FIELD: ionic plasma treatment of constructional materials. SUBSTANCE: method involves providing coaxial arrangement of discharge electrodes, with article be treated, for example tube, being used as one electrode; initiating vacuum electric discharge between electrodes by creating potential gap and exposing inner surface of tube to discharge plasma. Potential difference is created between cathode-tube made from non-magnetic stainless steel and anode made from non-magnetic material with length at least equal to that of tube to be treated. Plasma treatment is effectuated upon superimposition of magnetic field crossed with electric field onto discharge zone. Discharge current density is maintained within the range of 15-20 mA/cm², nitrogen pressure within the range of 2-5 Pa and magnetic induction within the range of 10-20 μTl. EFFECT: increased corrosion stability. 1 dwg