Slipring with reduced contact noise

1. A method for manufacture of a gold-plated slipring contact, the method comprising:

forming a first layer of copper by galvanically applying copper on an electrically-conductive substrate;

subsequently to said forming the first layer, creating a second layer of at least one of nickel and nickel phosphor by galvanically applying at least one of a layer of nickel and a layer of nickel phosphor on the first layer of copper; and

subsequently to said creating the second layer, forming a third layer of gold by galvanically applying gold on said at least one of (i) the layer of nickel and (ii) the layer of nickel phosphor;

wherein said galvanically applying copper is devoid of using, in the employed first galvanic bath, at least one brightener from the group of brighteners consisting of: 3-carboxy-1-(phenylmethyl)pyridinium chloride sodium salt, cationic polymers with urea groups, 1-(3-sulfopropyl)pyridinium betaine, 1-(2-hydroxy-3-sulfopropyl)-pyridinium betaine, propargyl(3-sulfopropyl)ether sodium salt, sodium saccharin, sodium allylsulfonate, N,N-dimethyl-N-(3-cocoamidopropyl)-N-(2-hydroxy-3-sulfopropyl)ammonium betaine, polyamines, 1H-imidazole-polymer with (chloromethyl)oxiran, 3-carboxy-1-(phenylmethyl)pyridinium chloride sodium salt, 1-benzyl-3-sodium carboxy-pyridinium chloride, arsenic trioxide, potassium antimony tartrate, potassium tellurate, alkali arsenite, potassium tellerite, potassium seleno cyanate, alkali antimonyl tartrate, sodium selenite, thallium sulfate, and carbon disulfide.

2. A method according to claim 1 , wherein

during said galvanically applying copper, no brightener from said group is used in an employed galvanic bath.

3. A method according to claim 1 , wherein

during said galvanically applying copper, a pure copper cyanide solution is used as an employed galvanic bath.

4. A method according to claim 2 , wherein said galvanically applying copper includes using a pure copper cyanide solution as said employed galvanic bath.

5. A method according to claim 1 , wherein

said galvanically applying copper includes galvanically applying copper with a first layer thickness of up to 4 μm.

6. A method according to claim 1 , wherein

said galvanically applying copper includes galvanically applying copper with a first layer thickness of up to 10 μm.

7. (Curently amended) A method according to claim 1 , wherein said galvanically applying the at least one of (i) the layer of nickel and (ii) the layer of nickel phosphor on the first layer of copper includes galvanically applying said at least one of the layer of nickel and the layer of nickel phosphor with a second layer thickness between 5 μm and 10 p.m.

8. A method according to claim 1 , wherein

said galvanically applying gold on the at least one of the layer of nickel and the layer of nickel phosphor includes galvanically applying gold with a third layer thickness between 3 μm and 9 μm.

9. A method according to claim 1 , wherein

said galvanically applying gold on the at least one of (i) the layer of nickel and (ii) the layer of nickel phosphor includes galvanically applying gold with a third layer thickness of 6 μm.

10. A method according to claim 1 , wherein at least one of the following conditions is satisfied:

a) said galvanically applying copper includes causing the first layer of copper to have a surface roughness characterized by at least one of Sa-value and Sq-value that is in a range from 200 nm to 1 μm as a result of lack of said at least one brightener in the first galvanic bath, wherein said at least one of Sa-value and Sq-value is measured according to an EN ISO 25178 standard on Geometric Product Specifications enacted by the International Organization for Standardization (ISO); and

b) said galvanically applying the layer of gold includes galvanically applying gold to form an outer surface of the contact with a surface roughness represented by at least one of Sa-value and Sq-value that is between 50 nm and 1,000 nm, wherein said at least one of Sa-value and Sq-value is measured according to the EN ISO 25178 standard.

11. A method for manufacture of a gold-plated slipring contact, the method comprising:

providing an electrically conductive substrate made of brass;

sequentially depositing a first layer of copper, a second layer of at least one of a layer of nickel and a layer of nickel phosphor, and a third layer of gold by:

galvanically applying copper on an electrically-conductive substrate by using a first electrolyte based on potassium cyanide to form said first layer;

galvanically applying at least one of the layer of nickel and the layer of nickel phosphor on the first layer of copper by using a second electrolyte to form said second layer; and

galvanically applying gold on said at least one of (i) the layer of nickel and (ii) the layer of nickel phosphor to form said third layer.

12. A method according to claim 11 , wherein

said applying copper on the substrate includes applying copper with a first layer thickness of up to 4 μm.

13. A method according to claim 11 , wherein

said applying copper on the substrate includes applying copper with a first layer thickness of up to 10 μm.

14. A method according to claim 11 , wherein

said applying the at least one of the layer of nickel and the layer of nickel phosphor on the first layer of copper includes applying a layer with a second layer thickness between 5 μm and 10 μm.

15. A method according to claim 11 , wherein

said applying gold on the at least one of the layer of nickel and the layer of nickel phosphor includes applying gold with a thickness between 3 μm and 9 μm.

16. A method according to claim 11 , wherein said applying gold on the at least one of the layer of nickel and the layer of nickel phosphor includes applying gold with a thickness of 6 μm.