METHOD OF PRODUCING PROTECTIVE ANTICORROSION COATINGS ON ALUMINUM ALLOYS WITH WELDED SEAMS Russian patent published in 2019 - IPC C25D11/04 C25D11/18 

FIELD: technological processes.

SUBSTANCE: invention relates to methods of obtaining protective anticorrosion coatings on articles, structures and structures with welded joints made of aluminum alloys, mainly structural, which are intended for operation under unfavorable conditions under the influence of aggressive media: at high humidity, for example, in the atmosphere of sea fog, in corrosion-active aqueous solutions. Method involves electrochemical treatment of alloy surface at voltage providing flow of plasma microdischarges at electrode-electrolyte interface, in electrolyte containing potassium tartrate C₄H₄K₂O₆⋅0.5H₂O and sodium fluoride NaF, followed by applying onto the treated surface a layer of ultrafine polytetrafluoroethylene UPTFE from its suspension in isopropanol and heat treatment of the obtained composite coating, wherein electrochemical treatment is carried out in galvanostatic mode with current density of 0.3–0.6 A/cm² for 1–3 min in electrolyte, which contains, g/l: potassium tartrate C₄H₄K₂O₆⋅0.5H₂O 10–15 and sodium fluoride NaF 0.5–1.0, note here that application of UPTFE layer is carried out by single dipping for 10–20 seconds into dispersion containing 160.0–200.0 g/l of UPTFE in isopropanol with 6.0–8.0 g/l of non-ionic surfactant with wetting agent function.

EFFECT: improved anticorrosive properties and durability of protective coatings on alloys of aluminum with welded seams, obtained simultaneously for entire surface, including surface of said seams, due to minimization of factors causing change of structure of weld and its equal strength with material of base alloy, with simultaneous reduction of costs and energy consumption for method implementation.

1 cl, 3 dwg, 4 ex