High speed electrolyte for hard gold plating
AURUNA® 8400 is used for the deposition of hard gold coatings in special high-speed equipment. The electrolyte is weakly acidic, citrate-free and has a wide working range with simple bath maintenance.
The deposited coatings are high-brightness, low-porosity, solderable, hard and abrasion-resistant, and exhibit consistently low contact resistance. They are therefore ideally suited for electrical components such as contacts, plugs and connectors on printed circuit boards.
AURUNA® 8400 was developed for high-speed gold plating in selective plating lines and continuous reel-to-reel systems. It shows stable long-term behavior even with strong electrolyte movement (flow, spray) and high current densities. AURUNA® 8400 can also be used as a pregold electrolyte.
The optional use of AURUNA® Inhibitor 2 offers the possibility of reduced gold consumption of up to 15%. The inhibitor results in sharp edge delineations - thus reducing the run-out zone width. Of course, the coating properties remain unaffected. The inhibitor can be removed without residue after coating by activated carbon cleaning.
Electrolyte characteristics
Electrolyte type
weakly acidic
Metal content
12 (2 - 18) g/l Au
pH value
4.2 - 4.4
Operating temperature
45 - 60 °C
Current density range
plant-dependent
Plating speed
plant-dependent up to 12 μm/min
Anode material
Pt/Ti (PLATINODE® Pt/Ti) or MMO 177
Coating characteristics
Coating
Gold nickel
Purity
approx. 99.7 wt.% Au, approx. 0.3 wt.% Ni
Colour of deposit
yellow
Brightness
bright to highly bright
Hardness of deposit
approx. 130 - 190 HV
Max. coating thickness
10 μm
Density of the coating
approx. 17 g/cm³
Advantages
Very high plating speeds
Lower gold content possible
Exceptionally wide working range
Stable long-term behavior
Easy electrolyte maintenance
Excellent coating properties
Applications
Connectors
Electrical contacts
Connector strips on printed circuit boards
