METHOD OF PRODUCING COATINGS ON SURFACES OF DEEP THROUGH HOLES WITH STRAIGHT AND CURVED AXES IN ARTICLES FROM VALVE METAL ALLOYS Russian patent published in 2019 - IPC C25D11/00 

FIELD: chemistry.

SUBSTANCE: invention relates to the field of electroplating and can be used in mechanical engineering and related industries. Method involves electrochemical oxidation of surfaces of holes when acid or alkaline solutions of electrolytes pass through them without using special baths, only inside the holes themselves with formation on surfaces of dense coatings, mainly consisting of oxides of valve metal of articles, as well as subsequent filling of formed coatings with distilled boiling water and its vapor. Oxidation is performed after insertion into the holes of special counter electrodes in the form of flexible cables from corrosion-resistant steels, on which insulators inert relative to solutions are pressed along central through holes to exclude the possibility of contact of cables and articles. Filling of coatings is performed to reduce their porosity by boiling distilled water in plugged holes, filling half the holes.

EFFECT: method enables to obtain coatings in which thickness and operating properties in middle zones are not less than 75 % of thickness values and operational properties near external surfaces.

1 cl, 8 dwg, 2 tbl, 2 ex