RU2280109C1 - Electrolyte for applying composition type nickel base electrochemical coatings - Google Patents

Abstract

FIELD: electrolytic metallurgy.

SUBSTANCE: electrolyte contains, g/l: nickel sulfate, 220; nickel chloride, 45; sodium or potassium acetate, 30; fullerene C₆₀, 0.025 - 0.050. Sliding friction coefficient of coatings applied with use of such electrolyte is lowered by 1.5 - 3 times.

EFFECT: lowered sliding friction coefficient of coatings.

1 tbl

Description

The invention relates to the field of electroplating and is intended to produce composite electrochemical coatings based on nickel.

With the development of electroplating, composite coatings that are applied from suspension electrolytes, i.e. electrolytes modified by the addition of finely divided powders or microfibers, when the particles of the dispersed phase are deposited by metal during electrodeposition, fixing on the surface of the product in a metal matrix.

Composite coatings are obtained in cases where it is envisaged to modify the surface of metal products to give them new properties (increase corrosion resistance, reduce friction and wear, increase hardness, etc.). Known electrolyte for the deposition of wear-resistant composite coatings, having the following composition, g / l: Nickel or cobalt sulfate 230-320; nickel or cobalt chloride 30-60; silicon carbide or alumina 25-85; molybdenum disulfide 4-20 (USSR author's certificate No. 1805697, IPC C 25 D 15/00, claimed on 05/14/1990 // Inventions. - 1995. - No. 29. - S.325). The disadvantage of this electrolyte is the high content of particles of the dispersed phase, which creates difficulties in the deposition of the coating, there are problems with the uniformity of the precipitate in thickness, the coating has a tendency to delamination.

Known electrolyte, allowing to obtain coatings of higher quality. It has the following composition, g / l: nickel chloride or cobalt chloride or iron chloride 300; boric acid 40; amorphous boron 10-40; ultrafine carbon condensate 2-140. Carbon condensate has the following composition, wt.%: Carbine 2-5; graphite 1-15; non-crystalline carbon 3-50; diamond - the rest (RF Patent No. 2026892, IPC C 25 D 15/00, filed 05.06.1990 // Inventions. - 1995. - No. 2. - P.150). However, the use of this electrolyte is limited by the high cost and scarcity of its constituent components, such as carbine and diamond. Obtaining the latter in a dispersed state is associated with significant difficulties not only of a technological, but also of an organizational nature (the use of explosion technology).

A well-known electrolyte described in the source was selected for the prototype: Timoshkov Yu.V., Gubarevich T.M., Orekhovskaya T.I. et al. Properties of composite nickel coatings with various types of ultrafine diamond particles // Electroplating and surface treatment. 1999, Vol. 7, No. 2, pp. 20-25. In terms of a combination of similar essential features, it is closest to the proposed technical solution. Known electrolyte has the following composition, g / l:

Nickel sulfate 240 Nickel chloride 40 Boric acid thirty Ultrafine diamond 2-20

A disadvantage of the known electrolyte is the presence of ultrafine diamond. To obtain it, explosive detonation synthesis is used and this significantly complicates the technology of electrolyte preparation. In addition, coatings deposited from this electrolyte have a high coefficient of friction, which reduces their wear resistance.

The claimed invention was tasked with creating a technologically simple electrolyte to prepare to obtain wear-resistant composite electrochemical coatings.

To achieve this, the electrolyte for the preparation of nickel-based composite electrochemical coatings contains nickel sulfate and nickel chloride, additionally contains the dispersed phase of fullerene C ₆₀ , and as a buffer additive contains sodium or potassium acetate in the following ratio of components, g / l:

Nickel sulfate 220 Nickel chloride 45 Sodium or potassium acetate thirty Fullerene C ₆₀ 0.025-0.050

The technical result obtained by using the claimed electrolyte is to reduce the sliding friction coefficient of coatings by 1.5-3 times.

The coating process is carried out at a cathodic current density of 6-10 A / dm ² and a temperature of 25 ° C. An electrolyte is prepared by dissolving each component in distilled water. Then, the salt solutions are filtered and poured from the electrolyte preparation baths into the storage tank, to which the required amount of an aqueous dispersion of fullerene C ₆₀ with an average particle size of 24 nm is added.

Specific examples illustrating the use of the invention are presented in table 1 "Effect of electrolyte composition on the coefficient of friction of coatings."

The table shows that the introduction into the electrolyte of dispersed particles of fullerene C ₆₀ leads to a decrease in the sliding friction coefficient of composite coatings. This is due to the fact that fullerene C ₆₀ , being included in the precipitate, serves as a dry lubricant. As follows from the table, the friction coefficients decrease with increasing content of fullerene C ₆₀ in the electrolyte. The reason for this is the increase in the content of particles of the dispersed phase in the coating with increasing concentration of fullerene C ₆₀ .

Thus, the proposed electrolyte allows to obtain high-quality protective coatings, leading to a decrease in the coefficient of sliding friction by 1.5-3 times. The proposed electrolyte can find application in various industries for modifying the surface of machine parts and mechanisms.

Table 1
The effect of electrolyte composition on the coefficient of friction of coatings Electrolyte composition, deposition mode and coating properties one 2 3 Prototype Sulfate content nickel sulfate nickel, g / l 220 220 220 240 Chloride content nickel chloride nickel, g / l 45 45 45 40 Acetate content buffer additives sodium or potassium, g / l thirty thirty thirty thirty non-metallic Fullerene content powder C ₆₀ , g / l 0,025 0,035 0,050 2-20 Electrolyte temperature ° C 25 25 25 fifty Cathode density current, A / dm ² 10 10 10 10 Coefficient of friction coatings 0.24 0.21 0.16 0.35-0.50

Claims (1)

An electrolyte for producing composite nickel-based electrochemical coatings, including nickel sulfate, nickel chloride and a buffer additive, characterized in that it additionally contains a dispersed phase of fullerene C ₆₀ , and sodium or potassium acetate as a buffer additive, in the following ratio of components, g / l: Nickel sulfate 220 Nickel chloride 45 Sodium or potassium acetate thirty Fullerene C ₆₀ 0.025-0.050