RU2476629C1 - Electrolytic coating application method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method involves deposition of the coating from electrolyte containing deposited metal ions and hardening additives in a suspended state; hardening additives are added in the quantity that is determined as per the following equation:

where z - quantity of hard inclusions in the coating, %, f₁ - coating friction coefficient without inclusions, f₂ - coating friction coefficient with inclusions, λ₁ - heat conductivity of the coating without inclusions, W/m·K, λ₂ - heat conductivity of the coating with inclusions, W/m·K.

EFFECT: increasing wear resistance of electrolytic coatings and reducing labour intensity for obtaining coatings owing to reducing the number of investigations.

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Description

The invention relates to the field of metallurgy, in particular to a method for applying electrolytic coatings with particles included in them, and can be used in the development and manufacture of wear-resistant coatings.

The known method [Reference construction materials. / Ed. B.N. Arzamasova; T.V. Solovieva. - M: MSTU Publishing House, 2005, p.160-162] for producing electrolytic coatings, which consists in introducing carbides, borides, oxides, diamond, corundum, etc. into the coating composition, which can significantly increase the wear resistance of coatings.

Known electrolytic method [RF patent 2224055 C1, class. C25D 11/02, 02.20.2004] applying anode coatings, which consists in treating the surface of the product in an electrolyte stream, creating from the external current source a potential difference of 100-1000 B between the part of the treated surface of the product, which is the anode and the second electrode of the opposite sign, with the initiation of microspark and microplasma discharges, the introduction of 3-20 wt.% fine powder of carbide, nitride, metal oxide or metalloid insoluble in the electrolyte into the electrolyte, while fine a powder of titanium and / or carbon and / or hydride of titanium and / or hydrocarbon compounds as an additive with an exothermic oxidation effect, with a dispersion of a mixture of powders of 1-5 μm, but not more than half the thickness of the coating layer, while the powders are introduced into a stream of electrolyte at the same time with their equal ratio, and the sum of both powders in the electrolyte is 3-20 wt.%.

Such methods require additional tests to determine the optimal amount of reinforcing additives in electrolytic coatings to ensure their best wear resistance.

The known method [RF patent 95102405 A1, class. C25D 11/02, 11/20/1996] electrolytic microarc coating on carbon steel products, which consists in applying a composition to carbon steel products (aluminum powder PAP-1 or PAP-2 25-35 wt.%, Al ₂ O ₃ (powder ) 25-35 wt.%, [CrAl ₃ (H ₃ PO ₄ ) _8.8-9.6 ] up to 100 wt.%), _Previously diluted in water in a ratio of 3: 1, and subsequent electrolytic microarc treatment in an alkaline electrolyte at a current density of 5-25 A / dm ² .

The disadvantage of this method is the wide range of determining the optimal number of incoming components to ensure maximum strength and wear resistance of the coating, which requires additional tests.

Closest to the proposed is the electrolytic method [RF patent 2109855 C1, cl. C25D 15/00, C25D 5/20, 04/27/1998] the preparation of composite coatings, which consists in carrying out the deposition process from an electrolyte containing ions of the deposited metal and insoluble particles in suspension when superimposed on the bath of ultrasonic vibrations directed parallel and perpendicular to the cathode surface.

The disadvantage of this method is to conduct additional tests to determine the optimal amount of hardening additives (fine powder of carbide, nitride, metal oxide or metalloid), providing maximum wear resistance of the coatings.

The objective of the invention is to increase the wear resistance of electrolytic coatings by optimizing the number of hardening additives, as well as reducing the complexity of obtaining coatings by reducing the number of tests.

The problem is solved in that in the method of applying electrolytic coatings with particles included in them, according to which the process of deposition from an electrolyte containing ions of the deposited metal and hardening additives in suspension is carried out, according to the invention, the number of hardening additives is determined by the equation:

where z is the amount of solids in the coating,%,

f ₁ - coefficient of friction of the coating without inclusions,

f ₂ - coefficient of friction of the coating with inclusions,

λ ₁ - thermal conductivity of the coating without inclusions,

λ ₂ - thermal conductivity of the coating with inclusions.

Powders of carbides, borides, oxides, diamond, corundum, etc. are used as hardening additives.

As a result of using the proposed method, the maximum wear resistance of electrolytic coatings with hardening additives is provided, reducing the number of studies in the development and manufacture of coatings.

An example of a specific implementation of the method

To obtain wear-resistant nickel-phosphorus coatings with the addition of silicon carbides, electrolytic deposition of coatings is carried out on vertical electrodes with magnetic stirring of the electrolyte. The electrolyte composition and electrolytic deposition parameters are presented in table 1.

Table 1 Electrolyte Composition and Process Parameters Electrolyte composition Electrolytic deposition parameters NiSO ₄ 6H ₂ O 300 g / l, pH 3.8 NiCl ₂ 6H ₂ O 45 g / l, temperature 50 ° C H ₃ BO ₃ 40 g / l current density 2 A / dm ² H ₃ PO ₃ 20 g / l, time 75 min silicon carbide suspension 0.80 and 200 g / l Nickel anode

Coefficients of friction of coatings, coefficients of thermal conductivity of coatings and the results of tribotechnical testing of electrolytic NiP coatings with different contents of silicon carbides in suspension during deposition are presented in table 2.

table 2 Tribological test results No. p / p Coating The number of additives in the matrix,% Coefficient of friction, f Thermal conductivity coefficient λ, W / (m · K) The amount of wear, 10 ⁶ μm ³ one. Nip 0 0.73 90.9 5.37 2. NiP-SiC, 80 g / l 26 0.65 120 5.15 3. NiP-SiC, 200 g / l 65 0.63 140 5.86

To determine the optimal amount of reinforcing additives of silicon carbides SiC, providing maximum wear resistance of electrolytic NiP coatings, the calculation is carried out according to the equation:

According to the calculations, when the content of silicon carbides in the matrix is about 30%, the wear of the coatings should be minimal. As can be seen from the table, the least wear is provided by the electrolytic NiP coating with a silicon carbide content of 26%.

As a result of using the proposed method, a reduction in the number of studies to determine the optimal number of hardening additives in electrolytic coatings, ensuring their maximum wear resistance, is provided.

So, the claimed method allows to determine the optimal number of hardening additives in electrolytic coatings with maximum wear resistance, reduce the complexity of the study of coatings.

Claims (1)

A method of applying electrolytic coatings with particles included in them, in which a deposition process is carried out from an electrolyte containing precipitated metal ions and hardening additives in suspension, characterized in that the hardening additives are introduced in an amount that is determined by the equation:

where z is the amount of solids in the coating,%,
f ₁ - coefficient of friction of the coating without inclusions,
f ₂ - coefficient of friction of the coating with inclusions,
λ ₁ - thermal conductivity of the coating without inclusions, W / m · K,
λ ₂ - thermal conductivity of the coating with inclusions, W / m · K.