AURUNA® 5400 Hard Gold Electrolyte

For Depositing Uniformly Bright Coatings

AURUNA® 5400 the weakly acidic electrolyte deposits yellow, uniform bright hard gold coatings. The newly balanced brightener system of the electrolyte enables the operation in a very wide current density working range and allows a variable gold content at the same time. Due to the usage of special chemical components, the AURUNA® 5400 is equally suitable for rack and barrel application.

The deposited coatings are characterized by low porosity and an increased abrasion resistance, compared to coatings deposited in AURUNA® 539. Furthermore contacts coated with AURUNA® 5400 exhibit a low and long-time stable contact resistance and an excellent solderability. As well coatings up to 10 μm can be crack-free depositied in the electrolyte.

Electrolyte characteristics

Electrolyte type

Weakly acidic

Metal content

8 (0.5 - 12) g/l Au

pH value

4.2 (3.8 - 4.6)

Operating temperature

50 (48 - 52) °C

Current density range

2.5 (1 - 5) A/dm²

Plating speed

0.1 - 1.0 μm/min

Anode material

MMO (type PLATINODE® 167 or 177)

Coating characteristics



Alloy composition

99.7 wt.% Au
0.3 wt.% Co

Colour of deposit




Hardness of deposit

150 - 220 HV

Max. coating thickness

Crack-free up to 10 μm

Density of the coating

Approx. 17 g/cm³


Type I-II, Code C-D
(equivalent to IC-IID according to MIL-G-45204C)


ZCT < 0.2 s


  • Very wide operating current density range
  • For technical and decorative applications
  • High corrosion and abrasion resistance
  • Low, stable contact resistance
  • Classification according to ASTM B 488-01: Type I - II, grade C -D


  • Contact pins, contact springs, contact plugs
  • Contact materials
  • 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.