DE1143075B - Process for the electrodeposition of copper and copper alloys? - Google Patents

Description

The invention relates to a method for the electrodeposition of copper and copper alloy coatings from an alkali metal cyanide bath containing a gluconate.

It is known per se to use alkali anide baths for the electrodeposition of copper, the one Have potassium gluconate content, with the deposition of copper superimposed by a direct current Alternating current takes place, whereby good deposits are to be achieved. In the relevant Publication is expressly emphasized that when using direct current alone here none satisfactory deposition is achieved, however, only when using the direct current superimposed alternating current Good separations can also be achieved without using the aluminum gluconate.

It has now been found that when certain gluconates are added in small amounts to alkali metal cyanide baths achieved very good results for the electrodeposition of copper and copper alloy coatings with good current yields. The invention accordingly relates to a method, wherein the Alkali cyanide bath at least 0.065 mol / liter of at least one of the following gluconates: alkali gluconate, Copper gluconate, ammonium gluconate, gluconic acid and glucondeltalactone can be added and the bath is operated by means of direct current under normal conditions.

Between 0.065 and 0.26 moles / liter, preferably 0.09 to 0.26 moles / liter, at least one is added to the bath Gluconate added.

As already mentioned, when using the baths according to the invention, improved current yields are achieved achieved, namely improved anode current yields especially at higher current densities than also improved cathode current yields when the alkali metal cyanide baths contain a gluconate in an amount of contain at least 0.065 mol / liter. The coatings made from such baths are smooth and fine-grained, so that further coatings of nickel or chromium are successfully applied to the coatings thus deposited and other metals can be deposited.

The alkali metal cyanide bath can also contain the usual other additives, such as primary shining agents Agents such as selenium and tellurium dithiocarbamates, e.g. B. Selenbisdiäthyldithiocarbamat, Rhodanin, Pseudothiohydantoin, 2,4-Dioxothiazolidine, etc., alone or in conjunction with secondary brighteners, such as lead, zinc, bismuth, antimony salts, etc.

The alkali metal cyanide baths can of course also contain the usual additives, such as wetting agents from processes for electrodeposition
of copper and copper alloys © » f λ

Applicant:

Metal & Thermit Corporation,

Rahway, NJ,
and Frank Passal, Detroit, Mich. (V. St. A.)

Representative: Dr.-Ing. H. Fincke, Dipl.-Ing. H. Bohr

and Dipl.-Ing. S. Staeger, patent attorneys,

Munich 5, Müllerstr. 31

Claimed priority:
V. St. v. America, June 19, 1957 (No. 666 767)

Frank Passal, Detroit, Mich. (V. St. A.),
has been named as the inventor

quaternary amines such as C-decylbetaine, trimethylbenzylammonium chloride or alkyl - ^ - aminopropionate, alkyl-ß-iminodipropionate, alkyl polyoxyethylene glycol ether etc., can be added.

Very good results are achieved with the present method when using electrodeposition a procedure is used in which the formation of a directly adhering to the cathode thin film is avoided, as a result of which there is a depletion of metal ions in the bath. this usually takes place by moving the bath, for example by pumping the solution, cathode movement, Stirring by introducing air or by diffusion effects, e.g. B. by power interruptions, periodic current controls etc. or a combination of these measures. Excellent Results are obtained when current interruptions are associated with cathodic movement can be applied.

The subject matter of the invention is explained in more detail in the following examples.

309 507/259

example 1

CuCN 26.1 g / liter

NaCN 34.5 g / liter

Na ₈ CO ₃ 30 g / liter

KOH 30 g / liter

Sodium gluconate 45 g / liter

(0.2 mol / liter) temperature 66 ° C

The bath was operated at current densities of 14, 28 and Amp./930 cm ² and produced fault-free precipitations with high current yields.

Example 2

CuCN 60 g / liter

KCN 90 g / liter

KOH 22.5 g / liter

Potassium gluconate 22.5 g / liter

(0.1 mol / liter)

Example 3

CuCN 60 g / liter

KCN 90 g / liter

KOH 22.5 g / liter

Potassium tartrate 22.5 g / liter

Flawless copper was obtained from the baths of Examples 2 and 3 under the same process conditions galvanically deposited. The process conditions and the resulting current yields are included in Table I below.

Table I.

Tabel II Gluconate Current density percent I (a) control Anode current efficiency 99.5 Amp./930cm ² (O Tartrate 92.6 5 100 (b) 46.2 10 93.1 99.6 13.4 20th 12.8 93.2 16.8 ₁₀ 40 3.0 16.3 50 1.1 2.9 11.4

This bath was also used with 60 g / liter additions of the compounds (a) and (b) listed above.

Example 5

CuCN 60 g / liter

KCN 90 g / liter

so KOH 22.5 g / liter

Sodium gluconate 30.75 g / liter

Current density (anode) 40 amps / 930 cm ²

The bath of Example 5 was kept in operation at 24 ° C for 1 hour at a total current of one ampere and an anode current density of 40 amps / 930 cm ² and gave fault-free electrodepositions with substantially higher anode powers than the same bath under the same Conditions using 52.3 g / liter potassium sodium tartrate or 44.4 g / liter potassium citrate.

The relevant anode weight loss and anode current yields are given in Table III.

space Amp./930cm ^J Percent electricity yield or
bath Cat
bath testicle
bath tempe
rature At
bath No. 3 No. 2 No. 3 approximately 50 No. 2 35.1 23.2 13.6 21 ⁰ C 25th 35.3 1.0 44.3 35.2 12.5 17.9 35.4 52.5 38.5 50 50.8 31.5 32.6 30.6 54 ° C 25th 25.6 37.7 87.1 82.1 12.5 59 98.1 83.9 80.8 50 97 8.41 61 59.1 65.56 ⁰ C 25th 30.1 68.9 85.5 78.9 12.5 96.6 103 99 96 104

35 Table III Gluconate citrate Tartrate 0.6679
28.2 0.0605
2.55 0.0812
3.43 ⁴⁰ Weight Loss (g) ...
Anode current efficiency
(%)

The results shown in the table above show the superiority of the bath of Example 2 compared to that of example 3.

Example 4

CuCN 60 g / liter

free KCN 11.2 g / liter

KOH 22.5 g / liter

Temperature 66 ° C

a) Potassium gluconate 15 g / liter

b) Potassium Sodium Tartrate 15 g / liter

c) No additional control

The bath of Example 4 was used with additives a) and b) and without additives. The results of the Experiments are included in Table II.

This bath was also at 66 ⁰ C and a current of 56 Amp./930 cm ^2, and using 22.5 g / liter gluconate operated and gave similar good results.

Example 6

CuCN 30 g / liter

KCN 67.5 g / liter

KOH 11.4 g / liter

K ₂ SnO ₃ -2H ₂ O 37.5 g / liter

Potassium gluconate 22.5 g / liter

(0.097MoI /
Liter)

This bath was at 54 and 66 ⁰ C and current densities of 10 6u, 30 and 50 cm ² Amp./930 operated and gave bright bronze deposits with excellent current efficiencies. The deposits are a little redder than those from baths of the same composition, with tartrates added instead of gluconates, and a deposit is obtained that contains more copper and less tin. This results from the greater copper current yield, which is characteristic of the bath.

Claims (1)

5 6 Example 7 application in the above baths good galvanic Never-3Q g / Lit _he would Dersch ^w with similarly improved current efficiencies, 67 5 g / liter * ^e * get ^it by the potassium and sodium salts _K0 H ". ' 11.4g / liter. ν en Vu r \ ii \ cn ; t »r ⁵ The error-free galvanic copper and copper alloy coatings made from alkali cyanide baths ,,. _ "_ .., obtained from the present invention are on This bronze bath with additions of 22 5, 45 and _{common base} metals such as iron, steel, nickel, 67.5 g / liter of potassium _{gluconate was tested against the zin} ^ _{lead> copper etc? and their l ieru} compared to the following example 8. _{10 available on certain base} metals, such as iron or -ι «Steel and finished castings based on zinc are based on the Example 8 Base metal first an initial thin coating The bronze bath corresponded to the composition of copper from a less effective cyanide of Example 7 with additions of 22.5, 45 and 67.5 g / copper bath deposited. Liters of sodium citrate. 15th The baths of Examples 7 and 8 were used in a patent claim:
Temperature of 68 ° C applied. Both 1. Methods of electrodeposition of copper and bronze anodes but in separate copper and copper alloy coatings from an experiment were used. In all investigated current alkali cyanide bath with a content of one density (10, 20, 30, 40 and 50 Amp./930cm ² ) for with 20 conat, characterized in that the baths operated with copper or bronze anodes were at least 0.065 mol / Liters of at least one, the anodic current yields obtained with the bath of the following gluconates: alkali gluconate, copper example 7, are higher than those obtained with the gluconate, ammonium gluconate, gluconic acid and example 8 bath. The average glucondeltalactone to be added and the bath current efficiency in 45 experiments, which were carried out from the bath of 25 by means of direct current under the usual conditions of Example 7, was 83 ° / ₀ ; at which is operated. Bath of Example 8, which is characterized under corresponding conditions 2. Method according to claim 1, characterized with those of the bath of Example 7, that the bath was operated between 0.065 and 0.26 mol /, the average flow liter, was preferably 0.09 to 0.26 mol / liter, poor yield 50.6 ^{% -3} ° of the least gluconate can be added. Additions of copper gluconate, ammonium gluconate, the other alkali metal luconates (Li, Rb, Cs), from publications considered: - Gluconic acid and glucondeltalactone give in An USA. Patent No. 2,548,867. © 309 507/259 1.63