AURUNA® 502 Rose Gold Electrolyte

Neutral, cadmium-free electrolyte for red layers

AURUNA® 502 is a neutral, cadmium-free gold copper electrolyte working without free cyanide. The red surfaces are bright, very hard and abrasion-resistant.

AURUNA® 502 is mainly used for decorative coatings, but it is suitable for technical applications such as slip rings as well. As gold-saving, low-carat layers, the surface exhibits very good corrosion and tarnish resistance.

The gold copper electrolyte can be used for rack and barrel plating, it can deposit layers of up to max. 10 μm in thickness.

Electrolyte characteristics

Electrolyte type


Metal content

4 (3.5 - 4.5) g/l Au
3 (2.5 - 3.5) g/l Cu

pH value

7.5 (7.2 - 8.0)

Operating temperature

57 (55 - 60) °C

Current density range

0.5 (0.3 - 0.8) A/dm²

Plating speed

Approx. 0.15 μm/min at 0.5 A/dm²

Anode material

Pt-Ti (type PLATINODE® Pt/Ti)

Coating characteristics



Alloy composition

75 wt.% Au
25 wt.% Cu

Colour of deposit





380 - 400 HV

Max. coating thickness

Approx. 10 μm

Density of the coating

Approx. 15 g/cm³


  • Gold-saving coatings (approx. 18 ct)
  • Cadmium-free
  • Red gold-copper layers
  • Resistant to tarnishing and corrosion
  • Maximum layer thickness approx. 10 μm
  • High hardness (380 - 400 HV), abrasion-resistant
  • Suitable for rack and barrel


  • Accessories
  • Jewellery
  • Watches
  • Bathroom fittings
  • Lighting
  • Spectacle frames
  • Writing implements
  • Slip rings
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Questions about the product?

Markus Legeler

+49 7171 607 204

For inquiries and additional information
please contact

Umicore AG & Co. KG
Rodenbacher Chaussee 4
63457 Hanau-Wolfgang

Tel.: +49 (6181) 59 6005
Fax: +49 (6181) 59 2970

The information and statements contained herein are provided free of charge. They are believed to be accurate at the time of publication, but Umicore makes no warranty with respect thereto, including but not limited to any results to be obtained or the infringement of any proprietary rights. Use or application of such information or statements is at the user´s sole discretion, without any liability on the part of Umicore. Nothing herein shall be construed as a license or recommendation for use, which infringes upon any proprietary rights. All sales are subject to Umicore´s General Conditions of Sale and Delivery.