DE2141940C2 - GALVANIC BATH FOR DEPOSITING TIN / NICKEL, TIN / COBALT OR TIN / NICKEL / COBALT COATINGS AND THE RELATED GALVANIZING PROCESS - Google Patents

Description

3 4

suitable bath can per liter in aqueous solution Example I

contain: Composition:

Nickel chloride NiQ ₂ · 6 H ₂ O .. 125-450 g nickel chloride NiQ ₂ · 6H "O 250 g

Tin (II) chloride SnCl ₂ · 2 H ₂ O 25 to 110 g Tin (II) chloride SnCl ₂ · 2 H ₂ O ... 50 g

Ammonium bifluoride NH ₄ F HF 20 to 100 g ⁵ ammonium _{bifluoride NH 4} F · HF .. 50 g

Amine 40 to 100 cm ^s diethylenetriamine 90 cm ³

(enough for pH (results in a pH of 4.8)

between 3.8 water rest

and 5.5)

Such a bath is set up, for example, by e ι s ρ ι e

initially nickel chloride, tin (H) chloride and Am composition:

monium bifluoride in the stated amounts approximately nickel chloride NiQ ₂ · 6 H ₂ O 250 g

400 cm ^{3 of} water are dissolved, then amine in a tin (II) chloride SnCl ₂ -2 H ₂ O ... 50 g

Amount is added until a pH host is 15 ammonium bifluoride NH ₄ F - HF .. 50 g

adjusts between 3.8 and 5.5, after which the remaining diethylenetriamine 110 cm ³

Lent volume with water to 11 bath liquid from hydrochloric acid 20 cm

is filled. Water rest

It has also proven advantageous to add organic acids, e.g. B. lactic acid, 20 example ΓΙΙ Citric acid, acetic acid, formic acid, sulfonic acid Composition

did. Through this to _f Ue the ability of the 20 ^ Α5u is |

Bath, the shine of the subsoil with the above 25 V ^ γ! ⁴ £ 75 _m

to maintain tensile strength, improves ^mm, gives a pH of 4.8)

Be ₁ the previously beschr.ebenen baths is the _Diätny ientriamin 20 cm ³

Armn, among other things, the task of de? pH value ^. _ ^J _ur 20 cm ³

of the bath to a range between 3.8 and 5.5 a ^, ^ _est

to deliver. Alternatively, the adjustment of the pH

Value can also be made using ammonia. B e i s π i e 1 IV

In such a case, the bath can be set up as follows

be: Composition:

Nickel chloride NiCl ₂ · 6 H ₂ O 250 g

Nickel chloride NiCI ₂ · 6 H ₂ O .. 200 to 300 g ₃₅ Tin (II) chloride SnCl ₂ · 2 H ₂ O ... 50 g

Tin (n) chloride SnCl ₄ -2 H ₂ O 40 to 60 g ammonium _{bifluoride NH 4} F - HF .. 50 g

Ammonium bifluoride NH ₄ F-HF 20 to 80 g ammonia 75 cm

Solution of amine and an or- (gives pH of 4.8)

Ganic and / or inorganic diethylenetriamine 30 cm ³

see, non-oxidizing acid 40 lactic acid 50 cm '

at a pH of 3.8 until water remains

5.5 30 to 80 cm ³

Ammonia enough for a pH of 1 V

3.8 to 5.5 Composition:

Of course it is also possible to use the bathroom "

Is preferably carried out with a bath which is set by the amine and / or ammonia to a pH value of 4.8 so.

The invention is also based on an electroplating process for depositing tin / nickel, tin /

■ ', KLcbsii cdcrZ: ™ s / N: ckc! / Kcbs! I-Schichicii ΰίΐί £ Γ VcF-turn a galvanic bath containing amine derivatives and fluoride or fluoroborate salts. The inventive method consists in giving the Dad ethylenediamine, diethylenetriamine, triethylenetetraamine. Mono-, di- and / or triethanolamine or pyridine added in an amount of up to 100 g / l will.

According to the invention, it is also provided that the work is carried out at a temperature of 60 to 90 ^° C., at a current density of 0.1 to 5 amperes / dm ² and at a pH of 3.8 to 5.5.

The following are some preferred bath compositions indicated, based in each case on 1 liter of finished bath liquid.

95 cm »

These baths were used at a bath temperature of 75 ° C. and an average current density of 4 amperes / dm ² . A nickel-

biccn vci turns. There were different items

such as jugs made of sheet brass, camera housings and bottle openers made of iron, door handles made of die-cast zinc, fruit juice presses made of aluminum, steel cladding of electrical appliances, printed electrical circuits, provided with tin / nickel coatings, which showed the same shine that was previously the objects, e.g. B. by nickel-plating. For base bodies made of iron, steel, copper. Nickel and brass could break open the coatings immediately! while base bodies made of die-cast tin or aluminum were previously copper-plated. The coatings were found to be extremely corrosion-resistant and very ductile.
It has also been shown that swan

changes in the bath composition, for example due to the consumption of the individual components, are not critical for the process and no noticeable changes in the appearance of the tin-nickel coatingc appear. From this point of view, the addition of an acid, particularly hydrochloric acid, turned out to be very good advantageous. . __,

Similar good coatings were also used with baths that contain cobalt salts instead of nickel salts or in addition contained cobalt salts in addition to nickel salts.

Claims (3)

2 141 9 * 0 ι 2 base body, so on the slopes of lower current density, increasingly matt. In addition, these patent claims: tin / nickel coatings have a strong reddish tinge, which is why these coatings generally enhance the aesthetic appeal 1. Galvanic, amine derivatives and fluoride or 5 sayings are not enough. In addition, the baths containing over * fluoroborate salts are very brittle to remove and tend to flake off, especially with larger deposits of tin-nickel, tin-cobalt or layer thickness. Furthermore, the tin-nickel-cobalt layers. bath management is difficult as a result, as narrow temperature tolerances indicate that ethylenediamine, di- must be adhered to. Tin / nickel coatings ethylenetriamine, triethylenetetraamine, mono-, di- io, despite their simpler production and / or triethanolamine or pyridine, have not yet been able to withstand chromium coatings by amounts of up to 100 g / l. can put, -, «*"" _Λ 2. Process for depositing shiny tin by German patents 1,260,915 and Nickel, tin-cobalt and tin-nickel-cobalt 1260916 are electroplated nn-Nickd baths using an electroplating, 15-know, which contains 0.05 to 2 g / l Tr .lmotriphenylmethane, Amine derivatives and fluoride or fluoroborate salts or 0.05 to 1 g / l l- (p-Ammop..2nyI) -3-methyIpyrazole containing bath, characterized in that it contains as brighteners, soft as building materials the bath ethylenediamine, diethylenetriamine, tri-act. The with these well-known bath ^ m deposited ethylenetetraamine, Mono-, di- and / or triethanol which coatings are, however, very sproae. amine or pyridine in an amount of up to 100 g / l. The object of the invention is to be galvanized. to create niche baths with which de ^r, gloss of 3. The method according to claim 2, characterized in that the background is uniform in depth that at a temperature of 60 to retained, bright (minimal or no reddish) 90 ⁰ C, at a current density of 0.1 to 5 A / dm ² Tin / nickel, tin / cobalt or tin / nickel / cobalt and worked at a pH value of 3.8 to 5.5 35 coatings of high ductility can be achieved,
will. Starting from a bathroom of the type mentioned at the beginning Art, this is achieved according to the invention in that there is ethylenediamine, diethylenetriamine, triethylenetetraamine, Mono-, di- and / or triethanolamine or - Contains 30 pyridine in an amount up to 100 g / l. As in-depth studies have shown, with even a small amount of amine added, for example of only a few grams per liter, the coatings with less red tinge and with greater ductility The invention relates to a galvanic, amine-based, and these effects occur with increasing amine derivatives and fluoride or fluoroborate salts are more apparent, with amine additives Holding bath for the deposition of tin / nickel, of about 100 g / l and more in terms of brightness Tin / cobalt or tin / nickel / cobalt layers and the ductility of optimal values can be achieved, an associated electroplating process. The gloss depth scatter is higher in places and It is common to find objects like car bumpers, 40 lower current density evenly. As a result of her Door or window fittings, clockwork parts, metallic low brittleness (high ductility) can die £ Decorative strips etc. are applied by galvanic chrome plating against coatings with a large layer thickness, Protect against corrosion. The galvanic chrome plating without the risk of flaking. the 4 has the disadvantages, however, that the bath is run. In terms of size, it is complicated and the so-called 45 that the underground previously owned. The invention Depth scatter is so small that hollow ware or thus offers the possibility of high-gloss tin / "For example, the concave back of car bumpers can be deposited with nickel layers by previously removing the cannot be chrome-plated. Base body a high-gloss surface, e.g. B. It is known that electroplated tin by nickel plating gives. Another ^v orteil of the bath nickel coatings, in which tin and nickel in about 50 according to the invention is that also this present on the same atomic number of equally good Üiierziehen of base bodies of iron with tin / ^ corrosion resistance such as chromium coatings have nickel , Tin / cobalt and tin / nickel / cobalt overlay and that in this process the depth scattering can be used, for which purpose the known ^ is much better than with chrome plating. In which tin-nickel wheels cannot be used. Article "Electrodeposition of Tin-Nicktl AI! Ey Piste ^ Ok named amines can be contained individually or also in from Chloride-Fluoride Electrolytes", Journal of Combination in the bathroom. Basically Electrochemical Society, Vol. 100, Nr..3, March 1953, all amines can be used which form salts with hydrofluoric acid or USA., Is in detail the galvanic coating of hydrofluoric acid, whereby objects are of course coated with a tin / nickel layer. the restriction applies that the respective amine was written at. There an electrolyte made of tin (II) - 60 bath working temperature in the bath is soluble, at least 50 g / l chloride, 300 g / l nickel chloride, sodium fluoride is partially soluble and must not be volatile.
28 g / l and ammonium binuoride 35 g / l are suggested. When you first start the bath, tin, nickel The coatings produced when such an electrolyte and optionally cobalt are added, however, are sulfate, sulfonate or chloride salts even when they are deposited. Here, on a z. B. high-gloss nickel-plated pad, 65 combinations can be provided by z. B. matt to at most semi-glossy, and in the case of hollow ware, nickel sulfate and tin (II) chloride are used next to each other or other uneven objects are to be used,
train, at the. hidden or deeper parts of the one for the production of tin / nickel coatings