PROCEDURE FOR APPLICATION OF WEAR RESISTANT COATING ON ALUMINIUM AND ITS ALLOYS Russian patent published in 2011 - IPC C25D11/12 C25D11/24 

FIELD: metallurgy.

SUBSTANCE: procedure consists in anodic coating in two stages in solution of silicate or aluminate of alkali metal at alternate current of 5-150 A/dm² density. According to the procedure at the first stage there is used solution of silicate or aluminate of alkali metal with concentration of 20-150 g/l in combination with fluorsilicate sodium of 2-20 g/l concentration. An item is conditioned in this solution for 20-40 min. At the second stage there is used alkaline solution os silicate or aluminate with concentration 2-10 g/l and concentration of alkali 0.5-4.0 g/l with conditioning for 1.5-2 hours. Also, upon anodic coating an item is treated with 50-65 % solution of hydrofluoric acid at temperature 30-60°C during 5-30 minutes. Further, it is washed in water and mechanically treated.

EFFECT: raised wear resistance, reliability and service life of coating at simultaneous intensification of process for fabrication of ceramic layer of coating with specified roughness.

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