SU1409680A1 - Method of stabilizing sulfate nickel-plating electrolytes - Google Patents

Abstract

The invention relates to methods for controlling the processes of electrodeposition of coatings and can be used to obtain shiny and matte nickel coatings with low internal stresses and relatively low microhardness. The purpose of the invention is to simplify and expand the technological capabilities of the method. This is achieved by the fact that the method of stabilization of nickel plating sulphate electrolytes involves the deposition of sulphate electrolyte coatings on the product by separating them from the anolyte with a cation-exchange membrane and anodic dissolution of nickel in the anolyte with pH 3-5, containing (g / l) nickel sulphate (hydrate) 1- 200; nickel chloride (hydrate) 3-400. The method makes it possible to stabilize the composition of sulfate electrolytes of opaque and brilliant nickel plating, from which coatings with internal voltages of 8.4-10.4 kg / mn and microhardness of about 140 kg / mm are deposited at densities of cathode current 1-5 A / dm 1 tab.

Description

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The invention relates to methods for regulating the processes of electro-coating of coatings and can be used to obtain bright and masking coatings with low internal voltages and relatively small microhardness. The purpose of the invention is to simplify and

The cathode, the microhardness of nickel coatings obtained in a sulphate electrolyte of nickel plating, is almost the same size as nickel coatings when chlorides are added to it — 50 g / l NiCl2 6H20 (respectively, from 132 to 150 kg / mm). Relatively small mic values

The 15th technological expansion possible ™ is characterized by hardness

her way.

The method of stabilization of sulfate nickel-plating nickel-plating involves carrying out a process of sedimentation of coatings from sulphate electrolytes to 5 products while separating them from the analyte: an aion-exchange membrane and anodic nickel dissolution in the anolyte containing, g / L

Nickel sulfate,

hydrate1-200

Nickel chloride,

hydrate. . 3-400 pH3-5

Example 1 A tank for anosilicon consisting of a casing and the MK-40 cation-exchange membrane fixed in it, is filled with a solution and placed into the nickel plating bath so that the cation-exchange membrane is oriented towards the cathode. The anode is shifted to the anolyte. When nickel coatings are applied to parts, the node dissolves and nickel ions enter the scaling electrolyte through a cation-exchange membrane. The anolyte is sucked and the electrolysis conditions presented in the table are selected, so that the dissolution yield of nickel significantly (by) exceeds the deposition rate of nickel from electrolyte nickel plating, which is 94-98%, which allows to maintain the concentration of ions in the electrolyte nickel plating at the required level. The insignificant accumulation of the concentration of nickel ions in the electrolyte makes it possible | partially | to partially compensate for the losses of nickel carried out by parts,

With the compositions of electrolytes and operating modes of electrolysis specified in the table, high-quality aluminum coatings of nickel are obtained. The quality of miniature coatings was evaluated on the basis of | anik data of measurements of microhardness and internal stresses, H1 and 55 hardness was determined by the method not in the recovered imprint, but by internal stress - by the method of deep 35

40

pH The internal voltages of nickel coatings obtained in a sulphate electrolyte are significantly less than nickel coatings obtained with the introduction of –50 g chlorides into it (respectively, from 12.1 to 16.8 kg / mm),

Example 2 With the anolyte compositions indicated in the table and the operating conditions of electrolysis, the process of brilliant nickel plating in the absence of chlorides is carried out. Composition of electrolytes, g / L, NiS04 7H O 300 | 3 saccharin 1.0, 1,4-butyndiol 0.5, pH - 4, At a cathode density of A / dm, t 50 ° C and stirring of the solution, high-quality brilliant nickel coatings are exposed. The contrast coefficient of specular reflection determined by the блесs-2 gloss of B 2 2 for the resulting bright nickel coatings is practically the same size (about 98%), as well as for the shiny nickel coatings obtained from the indicated electrolyte by introducing chlorides into it (NiCl , 50 g / l) ...

The technical and economic advantages of the proposed method are that it allows to simplify the process of adjusting the sulfate electrolyte, does not require the use of pumping -filtration of solutions and automatic control means can be realized in existing tanks without additional space and using NIN and other than In addition, electrolysis without chlorine recovery allows nickel to be recovered from the wash water, all of which simplifies the control of the electroplating process and significantly (for as long as 5 i.e. dy

The use of the method for stabilizing the ionic concentration of nickel during the deposition process allows preventing the oxidation of bilge-forming agents on the anode and, thus, expanding the technological capabilities due to

hardness characteristic of data

five

0

5 about -

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five

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pH The internal voltages of nickel coatings obtained in a sulphate electrolyte are significantly less than nickel coatings obtained with the introduction of –50 g / l chlorides (respectively, from 12.1 to 16.8 kg / mm),

Example 2 With the anolyte compositions and electrolysis operating conditions indicated in the table, the process of brilliant nickel plating is carried out in the absence of chlorides. Electrolyte composition, g / L, NiS04 7H O 300 | thirty; saccharin 1.0, 1,4-butyndiol 0.5, pH - 4, At a cathodic current density of A / dm, t 50 ° C and stirring of the solution, quality is obtained by exposure. Lightened nickel coatings. The comparative mirror reflection coefficient determined by a gloss of Φ B-2 for the resulting bright nickel coatings is almost the same size (on the order of 98%), as for the shiny nickel coatings obtained from this electrolyte when chlorides are added to it (NiCl, 50 g / l) ....

The technical and economic advantages of the proposed method consist in the fact that it allows to simplify the process of adjusting the sulphate electrolyte, does not require the use of pumping and filtration of solutions: and means of automatic control, can be realized in the existing tanks without additional space and, except for In addition, it allows nickel to be recovered from wash water by electrolysis without chlorine precipitation, all this simplifies the control of the electroplating process and significantly (in order of) 5i iHbmaeT electrical expenses.

The use of the method for stabilizing the ionic concentration of nickel in the deposition process makes it possible to prevent oxidation at the anode of the glossing agents and, thus, to expand the technological capabilities due to

using different formulations of electrolytes. In addition, the anode sludge does not enter the electrolyte and this allows operation without filtering the nickel electrolyte.

Claims (1)

Invention Formula A method for stabilizing sulphate electrolytes of nickel plating by introducing nickel ions into the electrolyte due to the electrochemical dissolution of the nickel anode in the process Electrodeposition of nickel coating on the product, characterized in that, in order to simplify and expand the technological capabilities of the method, the process is carried out in separating the products from the anode with a cation-exchange membrane and anolyte with a pH of 3-5, having a composition, g / l: Nickel sulfate (hydrate) 1-200 Nickel chloride (hydrate). 3-400  Table continuation