Cyanide-free electroplating baths for white bronze based on copper (i) ions

a technology of white bronze and cyanide, applied in the field of cyanide-free electroplating baths for white bronze based on copper (i) ions, can solve the problems of toxic white bronze, low current efficiency ranging from 50% to 80%, and relatively slow plating speed of 0.1, so as to achieve high current efficiency, high plating speed, good ductility

Inactive Publication Date: 2016-10-13
ROHM & HAAS ELECTRONICS MATERIALS LLC
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  • Summary
  • Abstract
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AI Technical Summary

Benefits of technology

[0006]The cyanide-free copper alloy electroplating baths deposit a bright, white bonze copper / tin alloy or cooper / tin / silver alloy. The copper alloy electroplating baths are stable over prolonged periods of time and deposit copper / tin alloys and copper / tin / silver alloys with high current efficiencies and high plating speeds in contrast to many conventional copper alloy baths which electroplate white bronze. The copper / tin alloys and copper / tin / silver alloys electroplated from the baths have good ductility, thermal stability and abrasion resistance. The copper / alloys may be directly plated with gold, chrome (III) or (VI), palladium and silver finishing layers without many of the conventional post-treatment steps of conventional processes such as ultrasonic rinse or cathodic degreasing. Therefore, the cyanide-free copper alloy electroplating bath enables more efficient processes than many conventional cyanide-free white bronze processes and may be used for nickel replacement.

Problems solved by technology

Presently, most industrial white bronze is not only toxic due to cyanide content but also has a relatively slow plating speed of 0.1 ASD to around 2 ASD with a low current efficiency ranging from 50% to 80%.
Although the plating speed of this electrolyte is significantly improved over many conventional white bronze electroplating baths, the white bronze deposit may be slightly brittle and unable to pass abrasion tests.
It may also be difficult to plate finishing top layers such as gold, chrome (III) or (VI), palladium or silver on white bronze.
This extra step reduces the efficiency and increases the cost of the overall process because ultrasonic equipment must be installed or in the case of cathodic degreasing separate tanks with current suppliers is needed.

Method used

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  • Cyanide-free electroplating baths for white bronze based on copper (i) ions
  • Cyanide-free electroplating baths for white bronze based on copper (i) ions
  • Cyanide-free electroplating baths for white bronze based on copper (i) ions

Examples

Experimental program
Comparison scheme
Effect test

example 1

Ternary White Bronze of Copper / Tin / Silver

[0039]The following aqueous acid white bronze electroplating bath was prepared:

TABLE 1CONCENTRATIONCOMPOUND(g / L)Copper (I) ions as copper oxide30Tin (II) ions as tin methane sulfonate12Silver (I) ions as silver methane sulfonate51-(2-dimethylamino-ethyl)-5-mercapto-961,2,3,4-tetrazole3,6-dithia-1,8-octanediol75Methane sulfonic acid (70%)150g / LAntimony as potassium antimony tartrate0.16Nonionic phenol ethoxylate10.8Hydroquinone monosulfonic acid1g / L1Adeka Tol PC-8: non-ionic surfactant, available from Adeka Corporation.

[0040]The pH of the bath was less than 1 as measured using a KNICK Instruments conventional laboratory pH meter. The molar mass of the tetrazole compound, 3,6-dithia-1,8-octanediol and copper (I) ions was 173.24, 182.30 and 63.55 g / mol, respectively. The mole ratio of the tetrazole to the cooper (I) ions in the bath was 1.2:1 and the mole ratio of the tetrazole to the 3,6-dithia-1,8-octandiol was 1.3:1.

[0041]A brass panel having...

example 2

Binary White Bronze of Copper / Tin

[0043]The following aqueous acid white bronze electroplating bath was prepared:

TABLE 2CONCENTRATIONCOMPOUND(g / L)Copper (I) ions as copper oxide14Tin (II) ions as tin methane sulfonate81-(2-dimethylamino-ethyl)-5-mercapto-421,2,3,4-tetrazoleThiodiethanol80Hydroquinone monosulfonic acid1.6g / LMethane sulfonic acid (70%)90g / LBismuth methane sulfonate0.021,10-Phenanthroline monohydrate0.01Nonionic phenol ethoxylate20.82Adeka Tol PC-8: non-ionic surfactant, available from Adeka Corporation.

[0044]The pH of the bath was less than 1 as measured using a KNICK Instruments conventional laboratory pH meter. The mole ratio of the tetrazole to the cooper (I) ions in the bath was 1.1:1 and the mole ratio of the tetrazole to the thiodiethanol was 0.4:1.

[0045]A brass panel having dimensions 10×7.5×0.025 cm was degreased cathodically at 4 ASD for 1 minute using RONACLEAN™ DLF solution and activated by immersing the substrate for 20 seconds in RONASALT™ 369 solution. Th...

example 3

Tetrazole / 3,6-Dithia-1,8-Octanediol Mole Ratio in a Copper / Tin / silver Electroplating Bath

[0047]The white bronze copper / tin / silver alloy electroplating bath was prepared as described in Example 1 with the exception that the amount of 3,6-dithia-1,8-octanediol was varied as shown in Table 3 below. The mole ratio of 1-(2-dimethylamino-ethyl)-5-mercapto-1,2,3,4-tetrazole to 3,6-dithia-1,8-octanediol was as shown in Table 3.

[0048]A plurality of brass panels having dimensions 10×7.5×0.025 cm was degreased and activated as described in Example 1 above. Each panel was then placed in separate Hull cells containing 250 mL of the white bronze bath. The pH of the bath was less than 1. A platinized titanium or bronze electrode was used as anode material. The working bath temperature ranged from 35° C. to 45° C. The panels were electroplated with the white bronze bath at 1 A for 3 minutes. Throughout electroplating all of the baths appeared stable.

[0049]After electroplating the panels were remove...

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Abstract

Copper alloy electroplating baths include one or more sources of copper (I) ions and one or more sources of tin ions to electroplate copper / tin alloys of mirror bright white bronze. The copper alloys may also include one or more sources of silver ions to electroplate ternary alloys of bright white bronze containing copper / tin / silver. The copper alloy electroplating baths are cyanide-free.

Description

FIELD OF THE INVENTION[0001]The present invention is directed to cyanide-free electroplating baths for white bronze based on copper (I) ions. More specifically, the present invention is directed to cyanide-free electroplating baths for white bronze based on copper (I) ions which are stable and electroplate bright white bronze deposits.BACKGROUND OF THE INVENTION[0002]White bronze is commonly used in decorative and sanitary industries as material for nickel replacement. In general, bronze is 40% to 70% by weight copper with the remainder tin or tin and silver or tin and zinc. It is hard enough, provides adequate wear and corrosion resistance such that it may be substituted for nickel in both decorative and sanitary functions. Presently, most industrial white bronze is not only toxic due to cyanide content but also has a relatively slow plating speed of 0.1 ASD to around 2 ASD with a low current efficiency ranging from 50% to 80%.[0003]U.S. Pat. No. 7,780,839 to Egli et al. is a cyani...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C25D3/58
CPCC25D3/58C25D5/10C25D5/12C25D5/627
Inventor FOYET, ADOLPHEGUEBEY, JONASCLAUSS, MARGIT
Owner ROHM & HAAS ELECTRONICS MATERIALS LLC
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