RHODUNA®-Alloy 1 Rhodium-Ruthenium Electrolyte

The first pure white electrolytic rhodium alloy

RHODUNA®-Alloy is the first alloy electrolyte in the world combining the high-quality metals rhodium and ruthenium. The basic materials of the new coating are truly royal: A mixture of rhodium, one of the world‘s most valuable precious metal, and the platinum group metal ruthenium.

Its white colour is absolutely equivalent to that of a pure rhodium layer. The electrolyte has all the quality characteristics of high-grade rhodium coatings and surpasses them in durability and uniformity. Its good throwing power even permits the plating of parts with complex geometries. It can be directly deposited on nickel, palladium, silver and gold.

At the same time, the „White Queen“ is considerably less expensive than pure rhodium layers.

Electrolyte characteristics

Electrolyte type

Strongly acidic

Metal content

1.6 (0.8 - 1.8) g/l Rh
0.4 (0.2 - 0.5) g/l Ru

pH value

< 1

Operating temperature

45 (40 - 50) °C

Current density range

4.0 (3.0 - 5.0) A/dm²

Plating speed

Approx. 0.2 μm/min at 4.0 A/dm²

Anode material

MMO (type PLATINODE® 187 SO)

Coating characteristics



Alloy composition

75 wt. % Rh, 25 % Ru

Colour of deposit





600 - 900 HV


  • Very light, white and ultra-bright coatings
  • More uniform layer thickness
  • Crack-free up to 1 μm
  • Wide current density range
  • Extremely abrasion-resistant
  • Less expensive than pure rhodium layers
  • Ideal for parts with complex geometries, e.g. chains
  • Suitable for rack and barrel


  • Spectacle frames
  • Writing implements
  • Jewellery
  • Watches

back to top

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
Email: chemistry@umicore.com
Website: www.chemistry.umicore.com

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.