RHODUNA®-Alloy Black 1 Rhodium-Ruthenium-Electrolyte

Bring the day the elegance of night

Attractive, appealing and elegant. This is as true for the night as well as for precious metals. Surface finishing with RHODUNA®-Alloy Black 1 allows you to transfer this elegance to your products - also at daytime.

The electrolyte deposits a dark precious metal alloy of rhodium and ruthenium with a noble anthracite hue - without color shift. The coatings produced are extremely resistant to abrasion and offer a price advantage of almost 50 percent (August 2019).

RHODUNA®-Alloy Black 1 finally makes your customers‘ desire for dark precious metal surfaces a reality.

Further information can be found in our brochure.

Electrolyte characteristics

Electrolyte type


Metal content

1.0 (0.8 - 1.2) g/l Rh
1.0 (0.8 - 1.2) g/l Ru

Operating temperature

45 (40 - 50) °C

Current density range

2.0 (0.5 - 5.0) A/dm²

Plating speed

Approx. 0.04 μm/min
at 2.0 A/dm²

Coating characteristics



Alloy composition

50 % Rh
50 % Ru

Colour of deposit





600 - 900 HV

Max. coating thickness

0.5 μm

Density of the coating

Approx. 12.4 g/cm3


  • Very dark anthracite with high color constancy
  • Adjustable degree of blackness
  • Gloss-preserving
  • Uniform layer thickness
  • Up to 0.5 μm crack-free
  • Extremely abrasion resistant
  • Large applicable current range
  • Simple bath management
  • Significantly cheaper than pure rhodium layers
  • Base for deep black layers (RHODUNA® 471 Black)


  • Accessories
  • Jewelry
  • Watches
  • Eyeglasses
  • Fittings
  • Automobile interior
  • Writing implements
  • Contacts

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

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