METHOD OF MAKING PROTECTIVE COATS ON SURFACES OF ARTICLES MADE FROM MAGNESIUM AND MAGNESIUM-BASED ALLOYS Russian patent published in 2005 - IPC

FIELD: electrochemical treatment of magnesium and magnesium-based alloys; making heat-resistant corrosion-protection coats.

SUBSTANCE: proposed method includes dipping the article in alkaline aqueous electrolyte containing fluoride followed by micro-plasma oxidation; for obtaining at least one phase layer of protective coat on surface, oxidation is performed in electrolyte containing 0.5 to 10 g/l of fluorides; oxidation is performed at electrolyte temperature of 10°C to 21°C and symmetric AC which spontaneously changes to asymmetric current. Minimum duration of oxidation is equal to time at which ratio of amplitude magnitudes of anode voltage to cathode voltage reaches 4-6.

EFFECT: enhanced corrosion resistance of protective coats; increased productivity at reduced power requirements; enhanced ecological safety; increased service life of electrolyte.

2 cl, 1 tbl, 2 ex