RU2524462C1 - Solution for chemical deposition of composite nickel coatings - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: solution contains, g/l: nickel dichloride 10-15, succinic acid 12-15, sodium fluoride 2-3, sodium hydroxide 4-6, sodium hypophosphite 17-20, copper-polymer complex of polyvinyl pyrrolidone 2.0-6.0, potassium polytitanate 10-30, distilled water - the balance.

EFFECT: solution enables to obtain composite coatings, having high wear resistance and low coefficient of friction, which prolongs the service life of friction assemblies.

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Description

The invention relates to the field of deposition of metal coatings on steel parts by chemical deposition and can be used in mechanical engineering, instrumentation and other industries.

Known nickel-phosphorus coatings containing various additives and alloyed with other metals (Vishenkov SA Chemical and electrochemical methods of deposition of metal coatings. - M .: Mashinostroenie, 1975). Inert particles are introduced into the chemical nickel plating solution and are precipitated together with nickel, forming composite coatings.

The closest (prototype) in composition and technical essence is "Solution for the chemical deposition of composite Nickel coatings" (patent No. 2235803 publ. September 10, 2004, bull. No. 25), the following composition, g / l:

Nickel dichloride 10-15 succinic acid 12-15 Sodium Fluoride 2-4 Sodium hydroxide 5-7 Sodium hypophosphite 17-20 Mercupral 0.5-1.2 Polymer water solution 2-6

The disadvantage of the composite coating of the prototype is the high coefficient of friction at higher speeds of the friction units and, as a result, lower wear resistance.

The authors were faced with the task of reducing the coefficient of friction and increasing the wear resistance of composite coatings for working in friction units at high speeds.

The problem is solved in that in a solution containing nickel dichloride, succinic acid, sodium fluoride, sodium hydroxide, sodium hypophosphite, an additional copper-polymer complex based on polyvinylpyrrolidone and potassium polytitanate is added, the components are taken in the following ratio, g / l:

Nickel dichloride 10-15 succinic acid 12-15 Sodium Fluoride 2-3 Sodium hydroxide 4-6 Sodium hypophosphite 17-20 Copper-polymer complex of polyvinylpyrrolidone 2.0-6.0 Potassium Polititanate 10-30 Distilled water Rest

The essence of the invention lies in the fact that the introduction of a copper-polymer complex based on polyvinylpyrrolidone into a chemical nickel solution increases the stability of the solution and at the same time ensures uniform distribution of potassium polytitanate in the volume of the solution in suspension, not allowing it to precipitate during the reaction, which in turn contributes to its uniform distribution in the coating, and, as a result, to the improvement of the performance of the composite coating

The copper-polymer complex of polyvinylpyrrolidone is a blue solution. The introduction of this substance into the coating contributes to the implementation of the effect of selective transfer in the friction process.

Potassium polytitanate is a white powder with a scaly nano structure. Its introduction into the coating composition will contribute to increasing wear resistance and reducing the coefficient of friction.

The copper-polymer complex of polyvinylpyrrolidone is a blue solution obtained by introducing a 10% aqueous solution of polyvinylpyrrolidone into a 10% aqueous solution of copper tetraammiakate.

During the preparation of the solution, each component (nickel dichloride, succinic acid, sodium fluoride, sodium hydroxide, polyvinylpyrrolidone) is dissolved separately in distilled water at a temperature of 18-25 ° C, then poured into a single solution after filtration.

The copper-ammonia polyvinylpyrrolidone polycomplex is introduced into the nickel plating solution just before the start of the process, the temperature of the solution is brought to 35-40 ° C, loaded into the product bath, sodium hypophosphite is added, then the process is conducted at a temperature of 75-80 ° C. Coating time 1 hour.

Compositions for chemical deposition of composite coatings are presented in table 1.

Table 1 Compositions of solutions for chemical nickel plating Components Content, g / l one 2 3 Prototype Nickel dichloride 10 10 10 10 succinic acid 12.0 12.0 12.0 12.0 Sodium Fluoride 2.0 2.0 2.0 2.0 Sodium hydroxide 4.0 4.0 4.0 4.0 Mercupral - - - 0.5 Polymer water solution - - - 2.0 Copper-ammonia polyvinylpyrrolidone polycomplex 2 2 2 - Sodium hypophosphite 20,0 20,0 20,0 17.0 Potassium Polititanate 10 twenty thirty - Distilled water Rest

Composite coatings from the developed formulations were applied to steel products (CT45). Sample preparation before applying composite coatings was carried out according to well-known methods (S. Vishenkov. Chemical and electrothermochemical methods of deposition of metal coatings. - M .: Mashinostroenie, 1975). The quality assessment of composite coatings from the proposed solutions was evaluated by the change in the coefficient of friction, linear wear and thickness of the coatings. The test results are presented in table 2.

table 2 Properties of coatings obtained from the proposed solutions Indicators Units rev. Solution number one 2 3 Prototype Friction coefficient at R _beats = 5 MPa, Y = 0.072 m / s, MS-20 oil 0.09 0.09 0.09 0.17 Linear wear μm 0,07 0,07 0,065 0,073 Coating thickness μm 17.5 19 twenty 16

As can be seen from the table, composite coatings from the proposed solutions have a lower coefficient of friction, low wear, increased service life of friction units.

Based on the foregoing, we believe that our solution for chemical nickel plating of metal products meets the requirement of "inventive step" and can be used in industry.

Conducted patent information search allows us to judge the novelty of the invention, and our solution can be protected by a patent of the Russian Federation.

Claims (1)

A solution for the chemical deposition of composite nickel coatings containing nickel dichloride, succinic acid, sodium fluoride, sodium hydroxide, sodium hypophosphite, characterized in that it additionally contains a copper-polymer polycomplex based on polyvinylpyrrolidone and potassium polytitanate in the following ratio of components, g / l:
Nickel dichloride 10-15 succinic acid 12-15 Sodium Fluoride 2-3 Sodium hydroxide 4-6 Sodium hypophosphite 17-20 Copper-polymer complex of polyvinylpyrrolidone 2.0-6.0 Potassium Polititanate 10-30 Distilled water Rest