RHODUNA® 470 Black Rhodium Electrolyte

Abrasion-resistant and crack-free dark coatings

RHODUNA® 470 Black adds a superior final layer to jewellery with a thickness up to 0.3 μm. The layer persuades with good corrosion resistance. The electrolyte is perfectly suited for applications where black ruthenium cannot fulfill the requested abrasion requirements.

The black rhodium electrolyte produces crack-free coatings, even at high layer thickness. The darkness can be adjusted. On the basic substrate, pre-gold plating or a pre-plating with rhodium is recommended.

It is absolutely essential to post-treat black rhodium-plated goods in RHODUNA® 470 Black Post Treatment for proper wear resistance and achieving a tarnish free surface.

Electrolyte characteristics

Electrolyte type


Metal content

2 (1.8 - 2.2) g/l Rh

pH value

< 1

Operating temperature

35 (30 - 40) °C

Current density range

2 (1 - 3) A/dm²

Plating speed

0.045 μm/min at 2 A/dm²

Anode material

Pt-Ti (type PLATINODE® Pt/Ti)

Coating characteristics



Colour of deposit

L*= approx. 63 (Anthracite) to L*= approx. 50 (Black) to
L*= approx. 45 (Deep Black)

Max. coating thickness

Approx. 0.3 μm

Abrasiveness Unassigned

Depending on degree of blackening excellent to fair


  • Perfect electrolyte for dark to black decorative layers
  • High abrasion resistance
  • Layer thickness up to 0.3 μm possible
  • Suitable for rack


  • Jewellery
  • Watches
  • Spectacle frames
  • Writing instruments
  • Accessories

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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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