METHOD OF PRODUCING COATINGS ON SURFACES OF THROUGH HOLES IN PRODUCTS FROM VALVE METAL ALLOYS Russian patent published in 2018 - IPC C25D11/02 

FIELD: technological processes.

SUBSTANCE: invention relates to the field of electroplating, in particular to the anodization and microarc oxidation of the surfaces of through holes of products from valve metal alloys, and can be used in engineering. Method includes electrochemical oxidation in acidic or alkaline solutions with a duration of 30–100 minutes when solutions are fed into openings, wherein oxidation is carried out inside the apertures themselves, axes of which are installed vertically and after half the processing time they reset the products with a rotation of 180° in the vertical plane, while in the holes are fixed with respect to the counter electrodes, stainless steel rods, in which the cross-sectional shape corresponds to the shape of the cross-sections of the holes, and the cross-sectional dimensions of the rods are 4–10 mm smaller than the corresponding cross-sectional dimensions of the holes, and under pressure from the bottom upwards, solutions are supplied into the gaps between the surfaces of the holes and rods during the laminar flow of solutions, maintaining their flow in the interval 0.2–5.0 l/min per 1 dm² area of the treated surfaces.

EFFECT: production of oxide coatings on the surfaces of through holes having thickness and performance characteristics in the middle zones of the holes is not less than 85 %, respectively, of the thickness values and performance properties near the external surfaces of products, without the use of electrochemical oxidation baths.

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