METHOD OF COATING APPLICATION ON ALUMINIUM ALLOYS Russian patent published in 2015 - IPC C25D11/06 

FIELD: metallurgy.

SUBSTANCE: method includes application to the aluminium alloy of the oxidation coating by plasma electrolythic oxidation in water electrolyte upon alternating current application with effective density 5-60 A/dm². Additionally modifying treatment of the aluminium alloy surface is performed in water solution containing in g/l: nitric acid 450-500 and sodium fluoride 45-50, then plasma electrolythic oxidation under alternating current is performed, current is produced by sequences of anode and cathode pulses with time interval between them, at that each pulse width is 100-250 microsec, and duration of time interval is at least total width of anode and cathode pulses. Water electrolyte has the following composition in g/l: sodium tetraborate 10-water 20-50, sodium hydrate 1-4, sodium molybdate 0.5-2, boracic acid 5-15.

EFFECT: creation on high alloyed aluminium alloys of the uniform in terms of thickness wearproof oxide coating with increased protection properties, on which the surface layer of aluminium oxide either is absent, or has low thickness, reduced roughness and labour content per mechanical removal of the surface layer.

2 cl, 1 tbl, 5 ex