SOLUTION FOR CLEANING AND PASSIVATING THE SURFACE OF STAINLESS STEEL ARTICLES AND A METHOD FOR CLEANING AND PASSIVATING USING SAID SOLUTION Russian patent published in 2025 - IPC C23F1/28 C23G1/08 C23C22/50 

FIELD: chemistry.

SUBSTANCE: group of inventions relates to chemical treatment of metals and includes a solution and a method for cleaning and passivating the surface of stainless steel articles. Solution for cleaning and passivation of stainless steel surface contains salts of ferrous and trivalent iron in ratio 40/60-10/90, nitrogen-containing compounds with oxidation state N^-1, in amount below their solubility limit in solution, organic acid in an amount providing pH of the solution of not more than 3.5, and surfactants in an amount of not more than 20 ml/l of the solution. Solution may contain hydrogen peroxide, orthophosphoric acid, hydroxylamine salts as nitrogen-containing compounds with oxidation state N^-1, citric acid or an acid from a group of mono- and dibasic carboxylic acids as an organic acid and mixture of 2-ethylhexanol alkoxylates or a mixture of polydimethylsiloxyethyl dimethicone derivatives and a distearate as a surfactant. Method of cleaning and passivation using said solution is characterized by simultaneous cleaning and passivation of the surface of the article with a solution flow rate of not less than 0.1 l/m² of the area of the treated surface.

EFFECT: cleaning of stainless steel surface from various contaminants and simultaneous surface passivation, reduction of processing time, number of technological operations and solution consumption.

9 cl, 5 tbl