SU1425258A1 - Zinc-plating electrolyte - Google Patents

Abstract

The invention relates to the deposition of galvanic zinc coatings and can be used in mechanical engineering, instrument making, radio engineering, electronic and other industrial sectors. The purpose of the invention is to expand the range of operating current density. The galvanizing electrolyte contains, g / l: zinc compound (in terms of metallic zinc) 8-25, alkali metal hydroxide 80-200, aromatic aldehyde 0.01-0.2, poly-N, N-dimethyl-N, N-diallyl ammonium nitride 1-20. The use of chapi-S, K-dimethyl-H, K-diallylammonium chloride as a polymer additive allows the working current density range to be expanded to 0.2–7 A / dm. Electrolyte dispersing ability is up to 57% (Hull's cell), current output is 90-100%. 2 tab. WITH/)

Description

The invention relates to the field of electroplating, in particular zinc, and can be used in the field of machine building, as well as in the instrument engineering industry of radio, electronic and other industries.

Purpose of the Invention: Spraying a range of operating current density

The galvanizing electrolyte contains a zinc compound, alkaline hydroxide, aromatic aldehyde j as a polymeric nitrogen-containing additive - poly-N, N-dimethy N N-di; alkyl lithium chloride of the general formula;

- (CH2 - CH-CK-CH2t.j

I

CHg CH,

ir c.f

SNS SNZ

 where n 12-3000,

with the following component ratio

g / l:

Connection 1 (in

metal based

cic zinc) 8-25

Alkali Hydroxide80--200

Aromatic aldegpdOjOI-OsZ

IIonH-N e H-dime

til-nuk-diallyl

ammonium chloride

specified . .

Formula1.0-20 About

The use of this polymer additive provides high polarization during electroplating, which contributes to obtaining crystalline, light, non-porous coatings during and; insertion of parts very complex in profile. The presence in the polymer molecule of quaternary nitrogen atoms that are not capable of protonization days, determines the improved technological properties of the proposed electrolyte,

In addition to TorOj, the molecular weight of the polymer is quite high, and the high density of polarity charges on the polymer chain makes it possible to efficiently precipitate and remove hydro-saline salts and other impurities5, which also help the water to clean up the water.

0

five

0

0

five

;

0

five

0

electrolyte operation under production conditions.

The preparation of this polymer additive consists in the radical polymerization of N, N-dimethyl-N, N-diallylammonium chloride. Depending on the polymerization conditions, the molecular weight of the polymer can vary over a wide range. mol. mass 2000-480000, - Polymers with smaller molecules and their mass are not effective if the molecular weight is higher than 500,000, then the properties of the zinc coatings deteriorate. This polymer is a white hygroscopic powder, soluble in 1 st in a syda, infusible ileto-shu5 maototoksichny (MPC in water OZ g / l). The toxicological characteristics of the polymer are such that they allow it to be used in the food (antiseum-biotic) purification of food and medical equipment as well as for the purification of drinking water. This polymer is a thermally and chemically stable product in a wide range of pH (0.5-13.5). Aqueous solutions of the polymer are stable - NECK and; -; it has been stored for more than a year without altering the structure. High dissolvability in aqueous alkaline solutions (ke is salted out from aqueous solutions containing alkali more than 200 g / l) allows the use of nanoparticulate solutions with a high concentration of alkali, 7dink ions, and a polymeric additive.

Caustic potash and caustic soda can be used to prepare zincate electrolyte in a series of alkalis, and c. As zinc compounds, it is an oxide; dink5 sulfur dioxide, chlorine-5 acetic acid DJIHK and others., Zinc oxide and caustic soda are preferred more economically than with economic considerations, as well as from the point of view of increasing the interchangeability of cyanide and nickel-free electrolytes.

The amount of alkali and the u-2nc compound in the electrolyte must be sufficient-i to form shch kohl Shleksn X ions, except ao,. must provide a zat1; the stability of the solution and the spark penetration of the anodes during the operation of the electrolyte. The optimal concentration of the compounds of the lung is 10–15 g / l (in terms of zinc) and alkali 1 20–160 g / l.

, 142

but, based on the specific technological problems, any other ratios can be used within the limits indicated above.

The concentration of the polymer additive in the electrolyte is 1-20 g / l. If the concentration of the additive is less than 1 g / l, then the effect of its influence on the process of electrodeposition of the coatings decreases, if the concentration of the additive is more than 20 g / l, then this is impractical as the cost of electrolyte increases.

To improve the appearance of the coatings, the known brilliance agents of the Aromatic Aldehyde class (3-methoxy-4-hydroxybenzaldehyde 2-hydroxybenzaldehyde; 3-hydroxy-4-methoxybenzaldehyde; 3,5-dimethoxy-D-hydroxybenzaldehyde) are introduced into the electrolyte.

Bisulfite derivatives can be used along with aromatic aldehydes, as is well known in electroplating.

To prepare the electrolyte in 1/3 of the volume of the bath, the necessary amount of alkali is dissolved and a zinc compound is added at a temperature of 60-80 ° C with stirring. After cooling, the resulting zincate solution is diluted with water; to the calculated concentration of the components. The polymer additive is introduced into the electrolyte in the form of a 10-25% aqueous solution, aromatic aldehydes are pre-dissolved in hot water.

The compositions of the tested electrolytes are given in table. 1, the results of their tests - in table 2.

The interval of current density in which high-quality fine-crystalline crystals are deposited, without deterioration of the structure and burning of the coating, is determined in the Hull cell (electrolyte volume 260 ml, current 1 A, time 10 min, surface of the angular cathode 0.25 dm).

The appearance of the coatings is evaluated visually according to the requirements of GOST 16-875-71.

Cathode metal current output

determined using a copper coulombometer.

abilities are calculated according to the method of Nachinov and Kudr Vtsev.

The stability of the electrolyte is checked by comparing the results obtained in a freshly prepared electrolyte and in the same electrolyte after prolonged storage (30 days).

As a result of the tests, it was established (Table 2) that the proposed galvanizing electrolyte using poly-N, K-dimethyl-Y, N-diallyl mono-chloride allows to obtain fine-crystalline, dense, uniform in appearance coatings in a wider current density range 0.2–7 A / dm (lime electrolyte operates in the range of 0.2–4 A / dm). In addition, the proposed zinc electrolyte does not impede wastewater treatment.

The simplicity of the synthesis of this polymeric compound, as well as the low cost and availability of the proposed additive, make it possible to use the proposed electrolyte on a wide industrial scale. The most effective is the replacement of cyanic galvanizing electrolytes when galvanizing into the drum small, but complex in detail parts on automatic installations.

Claims (1)

Invention Formula A zinc electrolyte containing a zinc compound, an alkali metal hydroxide, an aromatic aldehyde, and a nitrogen-containing polymer additive, characterized in that it contains poly-N, H-dimethyl-N, N- as a nitrogen-containing polymer additive in order to measure the range of the operating current density. diallylammonium chloride of general formula -fCH2-CH-H-CH2tn SNO CH 3g1 " CHz CHj To estimate the scattering power, the zinc distribution over the crowd, obtained at the copper corner cathode in the same Hull cell with an average current density of 0.5 and 2 A / dm, is used. Dissipative where n 12-3000, in the following ratio tov, g / l: Zinc compound (in in terms of zinc metal) Alkali Metal Hydroxide Aromatic Aldehyde Konpoienta - “i. Zinc CJKHcb Zinc chloride i LilHK Contents of 1shik in terms of "etayl Caustic soda E1KY potassium VerartrovyP ajriiinermi 11 | ol11-X, K-d 1met1 L-K, M-d challyllm-likhlnd s | -Mytoxy oxenbenza | degnd . 2; -Rnroxy- 6 e zaldegi 4-Methoxy - C: ene zaldehyde ten ten 15 thirty sixteen thirty 50 35 8 80, 80 12,100 2A 200 814 80 о100 24 200 100 50 eleven 150 110 25 200 0,050,10,2 0.812537, -3101520 (mi 5 thousand) (MB 5 thousand) (mv 5 thousand) (iv 5 thousand) (mv 50 tk) (mv 50 thousand) (mv 50 thousand) (nv 200 thousand) (nv 20 tVyhm 20 thousand) 0.1 0.2 0.01 0.2 3 -GD1) oxa стstoxibvnsildehyde 3,5-Dimethoxy-oxnbsneallegKD nonH-N, N-AHMe- thyl-N, N-diallyl ammonium chloride of the indicated general formula t in with l and c and I sixteen thirty 50 35 50 110 14 about 100 24 200 eleven 25 100 150 200 0,050,10,2 0.1 0.1 0.1 0.1 Toica integral of density, and which are deposited high-quality metal coatings (cell Khupla), a / m A visual assessment of the quality of a coating of 10 μm (appearance and structure) in the specified range of current density 0.3-2 Light smooth strip 0.3-6 0.2-6 0.3-7 0.2-7 0.2-7 0.3-6 0.4-5 0.2-6 0.2-7 Light, Light, Light, Light, Light, Light, Matte, Light, Light, smooth small-fine-small-small-small-small-small-crystal-crystal-crystal-crystal-crystal-crystal - kr sta - crystalline lical lyclic Lichesky Lichesky licheskichesky, at D at D without yellow- 0.3, then -0.4 darkness otny shade of ten Current output,%, at current density. A / dm 0.5 2.0 4.0 Scattering power at the density of tos, A / dm: 0.5 2.0 Electrolyte stability in the process of long storage of ESh1 100 90 40 25 99 95 75 57 36 99 98 89 55 35 100 98 80 51 33 98 94 72 56 37 99 98 75 56 38 100 94 75 52 37 99 94 74 54 (, Resistant for 30 days, fully preserves technical parameters Compiled by R. Ukhlinov Editor N. Gunko Tehrad M. Didyk Proofreader L. Pilipenko Order 4742/26 Circulation 622 VNII1Sh State Committee of the USSR for inventions and discoveries 113035, Moscow, F-33, Rauisk nab. d. 4/5 TablMtsA 2 0.2-7 98 94 72 99 98 75 100 94 75 99 94 74 99 96 78 100 98 79 56 37 56 38 52 37 54 (, 58 37 52 35 Subscription