PROCEDURE FOR APPLICATION OF COATING Russian patent published in 2010 - IPC C25D11/08 C25D15/00 

FIELD: metallurgy.

SUBSTANCE: invention refers to electroplating. The procedure consists in micro-arc oxidation - MAO - during 60…90 min at density of current 25…35 A/dm². MAO is performed on surface of a part under pressure through a sprayer contacting a cathode. Oxygen is supplied at temperature 5…15°C and consumption rate 0.1…1.0 m³/min per m² of surface. Parts contacting the anode are imparted to progressive and rotary motions. Also MAO is carried out successively in four stages - first during 10 min in solution containing caustic potash (6…8 g/l) and boric acid (40…50 g/l), further during 15…20 min in solution containing caustic potash (6…8 g/l), boric acid (40…50 g/l), fine dispersed corundum 3…5 mcm (40…60 g/l) and chromium oxide (1…2 g/l), further during 25…30 min in solution containing caustic potash (6…8 g/l), boric acid (40…50 g/l), fine dispersed corundum 5…7 mcm (40…60 g/l), chromium oxide (1…2 g/l) and finally in solution containing caustic potash (6…8 g/l), boric acid (40…50 g/l), fine dispersed corundum 7…10 mcm (40…60 g/l), chromium oxide (1…2 g/l). During MAO there is used ultra sound of 20…25 kHz frequency. After MAO there is performed thermal treatment including conditioning within 5 minutes at temperature 430…450°C and pulse heating of 4…5 cycles each consisting of holding during 25…35 sec at temperature 750…800°C and cooling to temperature not exceeding 450°C.

EFFECT: increased thickness, hardness, breakdown voltage and electrical resistance of produced coating.

1 tbl, 5 dwg, 1 ex