RU2086712C1 - Electrolyte for depositing zinc-iron alloy - Google Patents

Abstract

FIELD: electrodeposition processes. SUBSTANCE: zinc-iron alloy is deposited onto worn surfaces of machine parts, in particular, hydraulic pump housings, cylinder block supports in internal combustion engines, gears, etc. Electrolyte contains, g/l: zinc sulfate, 250-300; iron chloride, 60-100; boric acid, 25; sodium fluoride, 10; and (C₆-C₁₂)-alkylammonium hydrochloride, 1-3. EFFECT: improved physico-mechanical characteristics of coating: adhesion strength, structure, and reduced dendrite formation. 1 tbl

Description

 The invention relates to electroplating, in particular to electrolytic deposition of a zinc-iron alloy in order to restore worn surfaces of machine parts, for example, hydraulic pump housings, seats for engine blocks, internal combustion, gearboxes, etc.

 Known electrolyte solutions for the deposition of zinc-iron alloys containing iron sulfate, zinc sulfate, aluminum sulfate, sodium sulfate and ascorbic acid. However, coatings obtained from these electrolyte compositions have insufficient microhardness and poor adhesion to the substrate. Electrolytes have a dispersing ability, are inefficient and are subject to oxidation and pollution. This is especially observed when applying them under non-stationary modes of electrodeposition of a zinc-iron alloy (wind-driven, flow-through deposition at various forms of current).

Closest to the invention is a known electrolyte solution for the deposition of zinc-iron alloy, containing in g / l:
Zinc sulfate 200-300
Iron sulfate 50-60
Aluminum sulfate 40-50
Sodium sulfate 50-60
Boric acid 20-30
Ascorbic acid 5-10
Sodium salt of naphthalene disulfonic acid 2-5
Coatings obtained from this electrolyte solution have an increased microhardness of 90-150 kg / mm ² .

 However, this electrolyte solution has a complex composition, it is difficult to adjust the composition in the process.

 Precipitation has a coarse-grained structure, low adhesion to the base and, when recovering parts from aluminum alloys, have a distinctive specific temperature coefficient of linear expansion. The electrolyte is prone to oxidation, dendride formation at elevated current densities and is inefficient under unsteady conditions of alloy deposition.

 The aim of the invention is to increase the physico-mechanical characteristics of the coating, the adhesion strength, improve the structure of the precipitate, the chemical resistance of the solution and reduce dendride formation.

The goal is achieved in that the electrolyte solution for the deposition of the zinc-iron alloy containing zinc sulfate, iron salt, boric acid, sodium salt and an organic additive is characterized in that in order to increase the physicomechanical characteristics of the coating, adhesion strength, and improve the precipitate structure, chemical resistance and reduce dendriroobrazovaniya solution in the electrolyte is introduced as iron chloride, iron salts as sodium fluoride, sodium salt, and as the organic additive primary alkylammonium hydrochloride (C ₆ -C ₁₂₎ with eduyuschem ratio, g / l:
Zinc Sulfate 250-300
Ferric Chloride 60-100
Boric acid 25
Sodium Fluoride 10
Alkylammonium primary hydrochloride (C ₆ -C ₁₂ ) 1-3.

Comparative analysis with the prototype allows us to conclude that the claimed composition of the electrolyte differs from the known introduction of new components, namely: iron chloride as iron chloride, sodium salt as sodium fluoride, as an organic additive primary alkylammonium hydrochloride (C ₆ -C ₁₂ ) .

Thus, the claimed technical solution meets the criterion of "novelty." Primary alkyl ammonium salts are introduced into the electrolyte solution, using the well-known technical reagent ANP-2, used in ore flotation as a collector, with the general formula R-NH ₂ NCl, where R = C ₆ H ₁₃ -C ₁₂ H ₂₅ ( primary alkylammonium hydrochloride, mixture of substances).

 The proposed composition of the electrolyte solution differs from the known one in that it is simpler in content, productive and meets the technological process when restoring parts under non-stationary conditions (flowing, on various forms of current). Coatings are smooth, dense with a fine-grained structure, with increased wear and corrosion resistance.

 Thus, this electrolyte solution allows us to conclude that the proposed solution meets the criterion of "significant differences".

 A solid alloy of zinc ion substitution is precipitated by iron ions, which ensures the physicomechanical characteristics of the precipitate, which are identical to the characteristics of the base of the aluminum alloy AK-4, AL-9, from which machine parts are made.

The recovery process of worn parts from aluminum alloys is recommended to be carried out at a temperature of 20-30 ^o C, cathodic current density of 40-60 A / dm ² and an electrolyte solution flow rate of 6 μm ³ / s. The speed of rotation of the cathode 30 rpm

 For experimental verification of the claimed composition were prepared 12 mixtures of ingredients, 3 of which showed optimal results (see table).

 The use of the invention will improve the physico-mechanical characteristics of the coating: adhesion, sediment structure, chemical resistance of the solution and reduce dendrite formation.

Claims (1)

An electrolyte for the deposition of zinc-iron alloy containing zinc sulfate, iron salt, boric acid, sodium salt and an organic additive, characterized in that it contains iron chloride as an iron salt, sodium fluoride as a sodium salt, and primary as an organic additive alkylammonium hydrochloride (C ₆ C _{1 2} ) in the following ratio of components, g / l:
Zinc sulfate 250 300
Ferric Chloride 60 100
Boric acid 25
Sodium Fluoride 10
Alkylammonium primary hydrochloride (C ₆ C _{1 2} ) 1 - 3d

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