SELECTIVE ETCHER OF MULTI-COMPOSITE ELECTROLYTIC COATINGS BASED ON TIN AND LEAD Russian patent published in 2019 - IPC C23F1/30 C23F1/44 

FIELD: technological processes.

SUBSTANCE: invention relates to chemical treatment of metals, in particular to liquid chemical removal of multicomponent tin and lead based galvanic coatings from dissimilar metals, and can be used in machine building, automotive industry and other industries and in agriculture. Selective etchant of galvanic coatings based on tin and lead contains, g/l: nitric acid 354÷450, iron nitrate (III) 120÷180, sodium chloride 1.0÷4.0, copper corrosion inhibitor 2.0÷4.0, copper corrosion inhibitor solvent 12.0÷24, etching catalyst 0.9÷12.0, steel corrosion inhibitor 0.1÷10.0, boron fluoride copper (II) 0.1÷10.0, copper nitrate 0.01÷0.07, sodium nitrate 4.0÷10.0, potassium fluoride 4.0÷12.0. As copper corrosion inhibitor, it contains at least one substance selected from a group comprising cyclohexylamine benzoate, octadecylamine, cyclohexylamine chromate. Copper corrosion inhibitor solvent contains at least one substance selected from a group comprising acetone, benzene and toluene. As a catalyst of the etching process, it contains at least one substance selected from a group comprising hydrazine sulphate, hydrazine chloride, hydrazine hydrate, and the steel corrosion inhibitor contains at least one substance selected from a group comprising syntanol ALM-20, synthanol ALM-10, substance 4-nonylphenol.

EFFECT: technical result is higher selectivity and rate of etching of multicomponent galvanic coatings based on tin and lead.

1 cl, 2 tbl, 1 ex